Commit message: avformat/avidec: Limit formats in gab2 to srt and ass/ssa

This prevents part of one exploit leading to an information leak

Found-by: Emil Lerner and Pavel Cheremushkin
Reported-by: Thierry Foucu <tfoucu@google.com>

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
CVE: CVE-2017-9993
CWE: CWE-200
Vulnerability description: FFmpeg before 2.8.12, 3.0.x and 3.1.x before 3.1.9, 3.2.x before 3.2.6, and 3.3.x before 3.3.2 does not properly restrict HTTP Live Streaming filename extensions and demuxer names, which allows attackers to read arbitrary files via crafted playlist data.

Project: FFmpeg

static int avi_extract_stream_metadata(AVFormatContext *s, AVStream *st)
{
    GetByteContext gb;
    uint8_t *data = st->codecpar->extradata;
    int data_size = st->codecpar->extradata_size;
    int tag, offset;

    if (!data || data_size < 8) {
        return AVERROR_INVALIDDATA;
    }

    bytestream2_init(&gb, data, data_size);

    tag = bytestream2_get_le32(&gb);

    switch (tag) {
    case MKTAG('A', 'V', 'I', 'F'):
        bytestream2_skip(&gb, 4);
        offset = bytestream2_tell(&gb);
        bytestream2_init(&gb, data + offset, data_size - offset);

        return avpriv_exif_decode_ifd(s, &gb, 1, 0, &st->metadata);
        break;
    case MKTAG('C', 'A', 'S', 'I'):
        avpriv_request_sample(s, "RIFF stream data tag type CASI (%u)", tag);
        break;
    case MKTAG('Z', 'o', 'r', 'a'):
        avpriv_request_sample(s, "RIFF stream data tag type Zora (%u)", tag);
        break;
    default:
        break;
    }

    return 0;
}

Project: FFmpeg

static int avi_load_index(AVFormatContext *s)
{
    AVIContext *avi = s->priv_data;
    AVIOContext *pb = s->pb;
    uint32_t tag, size;
    int64_t pos = avio_tell(pb);
    int64_t next;
    int ret     = -1;

    if (avio_seek(pb, avi->movi_end, SEEK_SET) < 0)
        goto the_end; // maybe truncated file
    av_log(s, AV_LOG_TRACE, "movi_end=0x%"PRIx64"\n", avi->movi_end);
    for (;;) {
        tag  = avio_rl32(pb);
        size = avio_rl32(pb);
        if (avio_feof(pb))
            break;
        next = avio_tell(pb) + size + (size & 1);

        if (tag == MKTAG('i', 'd', 'x', '1') &&
            avi_read_idx1(s, size) >= 0) {
            avi->index_loaded=2;
            ret = 0;
        }else if (tag == MKTAG('L', 'I', 'S', 'T')) {
            uint32_t tag1 = avio_rl32(pb);

            if (tag1 == MKTAG('I', 'N', 'F', 'O'))
                ff_read_riff_info(s, size - 4);
        }else if (!ret)
            break;

        if (avio_seek(pb, next, SEEK_SET) < 0)
            break; // something is wrong here
    }

the_end:
    avio_seek(pb, pos, SEEK_SET);
    return ret;
}

Project: FFmpeg

static int avi_probe(AVProbeData *p)
{
    int i;

    /* check file header */
    for (i = 0; avi_headers[i][0]; i++)
        if (AV_RL32(p->buf    ) == AV_RL32(avi_headers[i]    ) &&
            AV_RL32(p->buf + 8) == AV_RL32(avi_headers[i] + 4))
            return AVPROBE_SCORE_MAX;

    return 0;
}

Project: FFmpeg

static int avi_read_close(AVFormatContext *s)
{
    int i;
    AVIContext *avi = s->priv_data;

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st   = s->streams[i];
        AVIStream *ast = st->priv_data;
        if (ast) {
            if (ast->sub_ctx) {
                av_freep(&ast->sub_ctx->pb);
                avformat_close_input(&ast->sub_ctx);
            }
            av_freep(&ast->sub_buffer);
            av_packet_unref(&ast->sub_pkt);
        }
    }

    av_freep(&avi->dv_demux);

    return 0;
}

Project: FFmpeg

static int avi_read_header(AVFormatContext *s)
{
    AVIContext *avi = s->priv_data;
    AVIOContext *pb = s->pb;
    unsigned int tag, tag1, handler;
    int codec_type, stream_index, frame_period;
    unsigned int size;
    int i;
    AVStream *st;
    AVIStream *ast      = NULL;
    int avih_width      = 0, avih_height = 0;
    int amv_file_format = 0;
    uint64_t list_end   = 0;
    int64_t pos;
    int ret;
    AVDictionaryEntry *dict_entry;

    avi->stream_index = -1;

    ret = get_riff(s, pb);
    if (ret < 0)
        return ret;

    av_log(avi, AV_LOG_DEBUG, "use odml:%d\n", avi->use_odml);

    avi->io_fsize = avi->fsize = avio_size(pb);
    if (avi->fsize <= 0 || avi->fsize < avi->riff_end)
        avi->fsize = avi->riff_end == 8 ? INT64_MAX : avi->riff_end;

    /* first list tag */
    stream_index = -1;
    codec_type   = -1;
    frame_period = 0;
    for (;;) {
        if (avio_feof(pb))
            goto fail;
        tag  = avio_rl32(pb);
        size = avio_rl32(pb);

        print_tag("tag", tag, size);

        switch (tag) {
        case MKTAG('L', 'I', 'S', 'T'):
            list_end = avio_tell(pb) + size;
            /* Ignored, except at start of video packets. */
            tag1 = avio_rl32(pb);

            print_tag("list", tag1, 0);

            if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
                avi->movi_list = avio_tell(pb) - 4;
                if (size)
                    avi->movi_end = avi->movi_list + size + (size & 1);
                else
                    avi->movi_end = avi->fsize;
                av_log(NULL, AV_LOG_TRACE, "movi end=%"PRIx64"\n", avi->movi_end);
                goto end_of_header;
            } else if (tag1 == MKTAG('I', 'N', 'F', 'O'))
                ff_read_riff_info(s, size - 4);
            else if (tag1 == MKTAG('n', 'c', 'd', 't'))
                avi_read_nikon(s, list_end);

            break;
        case MKTAG('I', 'D', 'I', 'T'):
        {
            unsigned char date[64] = { 0 };
            size += (size & 1);
            size -= avio_read(pb, date, FFMIN(size, sizeof(date) - 1));
            avio_skip(pb, size);
            avi_metadata_creation_time(&s->metadata, date);
            break;
        }
        case MKTAG('d', 'm', 'l', 'h'):
            avi->is_odml = 1;
            avio_skip(pb, size + (size & 1));
            break;
        case MKTAG('a', 'm', 'v', 'h'):
            amv_file_format = 1;
        case MKTAG('a', 'v', 'i', 'h'):
            /* AVI header */
            /* using frame_period is bad idea */
            frame_period = avio_rl32(pb);
            avio_rl32(pb); /* max. bytes per second */
            avio_rl32(pb);
            avi->non_interleaved |= avio_rl32(pb) & AVIF_MUSTUSEINDEX;

            avio_skip(pb, 2 * 4);
            avio_rl32(pb);
            avio_rl32(pb);
            avih_width  = avio_rl32(pb);
            avih_height = avio_rl32(pb);

            avio_skip(pb, size - 10 * 4);
            break;
        case MKTAG('s', 't', 'r', 'h'):
            /* stream header */

            tag1    = avio_rl32(pb);
            handler = avio_rl32(pb); /* codec tag */

            if (tag1 == MKTAG('p', 'a', 'd', 's')) {
                avio_skip(pb, size - 8);
                break;
            } else {
                stream_index++;
                st = avformat_new_stream(s, NULL);
                if (!st)
                    goto fail;

                st->id = stream_index;
                ast    = av_mallocz(sizeof(AVIStream));
                if (!ast)
                    goto fail;
                st->priv_data = ast;
            }
            if (amv_file_format)
                tag1 = stream_index ? MKTAG('a', 'u', 'd', 's')
                                    : MKTAG('v', 'i', 'd', 's');

            print_tag("strh", tag1, -1);

            if (tag1 == MKTAG('i', 'a', 'v', 's') ||
                tag1 == MKTAG('i', 'v', 'a', 's')) {
                int64_t dv_dur;

                /* After some consideration -- I don't think we
                 * have to support anything but DV in type1 AVIs. */
                if (s->nb_streams != 1)
                    goto fail;

                if (handler != MKTAG('d', 'v', 's', 'd') &&
                    handler != MKTAG('d', 'v', 'h', 'd') &&
                    handler != MKTAG('d', 'v', 's', 'l'))
                    goto fail;

                ast = s->streams[0]->priv_data;
                av_freep(&s->streams[0]->codecpar->extradata);
                av_freep(&s->streams[0]->codecpar);
#if FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
                av_freep(&s->streams[0]->codec);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
                if (s->streams[0]->info)
                    av_freep(&s->streams[0]->info->duration_error);
                av_freep(&s->streams[0]->info);
                if (s->streams[0]->internal)
                    av_freep(&s->streams[0]->internal->avctx);
                av_freep(&s->streams[0]->internal);
                av_freep(&s->streams[0]);
                s->nb_streams = 0;
                if (CONFIG_DV_DEMUXER) {
                    avi->dv_demux = avpriv_dv_init_demux(s);
                    if (!avi->dv_demux)
                        goto fail;
                } else
                    goto fail;
                s->streams[0]->priv_data = ast;
                avio_skip(pb, 3 * 4);
                ast->scale = avio_rl32(pb);
                ast->rate  = avio_rl32(pb);
                avio_skip(pb, 4);  /* start time */

                dv_dur = avio_rl32(pb);
                if (ast->scale > 0 && ast->rate > 0 && dv_dur > 0) {
                    dv_dur     *= AV_TIME_BASE;
                    s->duration = av_rescale(dv_dur, ast->scale, ast->rate);
                }
                /* else, leave duration alone; timing estimation in utils.c
                 * will make a guess based on bitrate. */

                stream_index = s->nb_streams - 1;
                avio_skip(pb, size - 9 * 4);
                break;
            }

            av_assert0(stream_index < s->nb_streams);
            ast->handler = handler;

            avio_rl32(pb); /* flags */
            avio_rl16(pb); /* priority */
            avio_rl16(pb); /* language */
            avio_rl32(pb); /* initial frame */
            ast->scale = avio_rl32(pb);
            ast->rate  = avio_rl32(pb);
            if (!(ast->scale && ast->rate)) {
                av_log(s, AV_LOG_WARNING,
                       "scale/rate is %"PRIu32"/%"PRIu32" which is invalid. "
                       "(This file has been generated by broken software.)\n",
                       ast->scale,
                       ast->rate);
                if (frame_period) {
                    ast->rate  = 1000000;
                    ast->scale = frame_period;
                } else {
                    ast->rate  = 25;
                    ast->scale = 1;
                }
            }
            avpriv_set_pts_info(st, 64, ast->scale, ast->rate);

            ast->cum_len  = avio_rl32(pb); /* start */
            st->nb_frames = avio_rl32(pb);

            st->start_time = 0;
            avio_rl32(pb); /* buffer size */
            avio_rl32(pb); /* quality */
            if (ast->cum_len*ast->scale/ast->rate > 3600) {
                av_log(s, AV_LOG_ERROR, "crazy start time, iam scared, giving up\n");
                ast->cum_len = 0;
            }
            ast->sample_size = avio_rl32(pb);
            ast->cum_len    *= FFMAX(1, ast->sample_size);
            av_log(s, AV_LOG_TRACE, "%"PRIu32" %"PRIu32" %d\n",
                    ast->rate, ast->scale, ast->sample_size);

            switch (tag1) {
            case MKTAG('v', 'i', 'd', 's'):
                codec_type = AVMEDIA_TYPE_VIDEO;

                ast->sample_size = 0;
                st->avg_frame_rate = av_inv_q(st->time_base);
                break;
            case MKTAG('a', 'u', 'd', 's'):
                codec_type = AVMEDIA_TYPE_AUDIO;
                break;
            case MKTAG('t', 'x', 't', 's'):
                codec_type = AVMEDIA_TYPE_SUBTITLE;
                break;
            case MKTAG('d', 'a', 't', 's'):
                codec_type = AVMEDIA_TYPE_DATA;
                break;
            default:
                av_log(s, AV_LOG_INFO, "unknown stream type %X\n", tag1);
            }

            if (ast->sample_size < 0) {
                if (s->error_recognition & AV_EF_EXPLODE) {
                    av_log(s, AV_LOG_ERROR,
                           "Invalid sample_size %d at stream %d\n",
                           ast->sample_size,
                           stream_index);
                    goto fail;
                }
                av_log(s, AV_LOG_WARNING,
                       "Invalid sample_size %d at stream %d "
                       "setting it to 0\n",
                       ast->sample_size,
                       stream_index);
                ast->sample_size = 0;
            }

            if (ast->sample_size == 0) {
                st->duration = st->nb_frames;
                if (st->duration > 0 && avi->io_fsize > 0 && avi->riff_end > avi->io_fsize) {
                    av_log(s, AV_LOG_DEBUG, "File is truncated adjusting duration\n");
                    st->duration = av_rescale(st->duration, avi->io_fsize, avi->riff_end);
                }
            }
            ast->frame_offset = ast->cum_len;
            avio_skip(pb, size - 12 * 4);
            break;
        case MKTAG('s', 't', 'r', 'f'):
            /* stream header */
            if (!size && (codec_type == AVMEDIA_TYPE_AUDIO ||
                          codec_type == AVMEDIA_TYPE_VIDEO))
                break;
            if (stream_index >= (unsigned)s->nb_streams || avi->dv_demux) {
                avio_skip(pb, size);
            } else {
                uint64_t cur_pos = avio_tell(pb);
                unsigned esize;
                if (cur_pos < list_end)
                    size = FFMIN(size, list_end - cur_pos);
                st = s->streams[stream_index];
                if (st->codecpar->codec_type != AVMEDIA_TYPE_UNKNOWN) {
                    avio_skip(pb, size);
                    break;
                }
                switch (codec_type) {
                case AVMEDIA_TYPE_VIDEO:
                    if (amv_file_format) {
                        st->codecpar->width      = avih_width;
                        st->codecpar->height     = avih_height;
                        st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
                        st->codecpar->codec_id   = AV_CODEC_ID_AMV;
                        avio_skip(pb, size);
                        break;
                    }
                    tag1 = ff_get_bmp_header(pb, st, &esize);

                    if (tag1 == MKTAG('D', 'X', 'S', 'B') ||
                        tag1 == MKTAG('D', 'X', 'S', 'A')) {
                        st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
                        st->codecpar->codec_tag  = tag1;
                        st->codecpar->codec_id   = AV_CODEC_ID_XSUB;
                        break;
                    }

                    if (size > 10 * 4 && size < (1 << 30) && size < avi->fsize) {
                        if (esize == size-1 && (esize&1)) {
                            st->codecpar->extradata_size = esize - 10 * 4;
                        } else
                            st->codecpar->extradata_size =  size - 10 * 4;
                        if (st->codecpar->extradata) {
                            av_log(s, AV_LOG_WARNING, "New extradata in strf chunk, freeing previous one.\n");
                            av_freep(&st->codecpar->extradata);
                        }
                        if (ff_get_extradata(s, st->codecpar, pb, st->codecpar->extradata_size) < 0)
                            return AVERROR(ENOMEM);
                    }

                    if (st->codecpar->extradata_size & 1)
                        avio_r8(pb);

                    /* Extract palette from extradata if bpp <= 8.
                     * This code assumes that extradata contains only palette.
                     * This is true for all paletted codecs implemented in
                     * FFmpeg. */
                    if (st->codecpar->extradata_size &&
                        (st->codecpar->bits_per_coded_sample <= 8)) {
                        int pal_size = (1 << st->codecpar->bits_per_coded_sample) << 2;
                        const uint8_t *pal_src;

                        pal_size = FFMIN(pal_size, st->codecpar->extradata_size);
                        pal_src  = st->codecpar->extradata +
                                   st->codecpar->extradata_size - pal_size;
                        /* Exclude the "BottomUp" field from the palette */
                        if (pal_src - st->codecpar->extradata >= 9 &&
                            !memcmp(st->codecpar->extradata + st->codecpar->extradata_size - 9, "BottomUp", 9))
                            pal_src -= 9;
                        for (i = 0; i < pal_size / 4; i++)
                            ast->pal[i] = 0xFFU<<24 | AV_RL32(pal_src + 4 * i);
                        ast->has_pal = 1;
                    }

                    print_tag("video", tag1, 0);

                    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
                    st->codecpar->codec_tag  = tag1;
                    st->codecpar->codec_id   = ff_codec_get_id(ff_codec_bmp_tags,
                                                            tag1);
                    /* If codec is not found yet, try with the mov tags. */
                    if (!st->codecpar->codec_id) {
                        st->codecpar->codec_id =
                            ff_codec_get_id(ff_codec_movvideo_tags, tag1);
                        if (st->codecpar->codec_id)
                           av_log(s, AV_LOG_WARNING,
                                  "mov tag found in avi (fourcc %s)\n",
                                  av_fourcc2str(tag1));
                    }
                    /* This is needed to get the pict type which is necessary
                     * for generating correct pts. */
                    st->need_parsing = AVSTREAM_PARSE_HEADERS;

                    if (st->codecpar->codec_id == AV_CODEC_ID_MPEG4 &&
                        ast->handler == MKTAG('X', 'V', 'I', 'D'))
                        st->codecpar->codec_tag = MKTAG('X', 'V', 'I', 'D');

                    if (st->codecpar->codec_tag == MKTAG('V', 'S', 'S', 'H'))
                        st->need_parsing = AVSTREAM_PARSE_FULL;
                    if (st->codecpar->codec_id == AV_CODEC_ID_RV40)
                        st->need_parsing = AVSTREAM_PARSE_NONE;

                    if (st->codecpar->codec_tag == 0 && st->codecpar->height > 0 &&
                        st->codecpar->extradata_size < 1U << 30) {
                        st->codecpar->extradata_size += 9;
                        if ((ret = av_reallocp(&st->codecpar->extradata,
                                               st->codecpar->extradata_size +
                                               AV_INPUT_BUFFER_PADDING_SIZE)) < 0) {
                            st->codecpar->extradata_size = 0;
                            return ret;
                        } else
                            memcpy(st->codecpar->extradata + st->codecpar->extradata_size - 9,
                                   "BottomUp", 9);
                    }
                    st->codecpar->height = FFABS(st->codecpar->height);

                    break;
                case AVMEDIA_TYPE_AUDIO:
                    ret = ff_get_wav_header(s, pb, st->codecpar, size, 0);
                    if (ret < 0)
                        return ret;
                    ast->dshow_block_align = st->codecpar->block_align;
                    if (ast->sample_size && st->codecpar->block_align &&
                        ast->sample_size != st->codecpar->block_align) {
                        av_log(s,
                               AV_LOG_WARNING,
                               "sample size (%d) != block align (%d)\n",
                               ast->sample_size,
                               st->codecpar->block_align);
                        ast->sample_size = st->codecpar->block_align;
                    }
                    /* 2-aligned
                     * (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */
                    if (size & 1)
                        avio_skip(pb, 1);
                    /* Force parsing as several audio frames can be in
                     * one packet and timestamps refer to packet start. */
                    st->need_parsing = AVSTREAM_PARSE_TIMESTAMPS;
                    /* ADTS header is in extradata, AAC without header must be
                     * stored as exact frames. Parser not needed and it will
                     * fail. */
                    if (st->codecpar->codec_id == AV_CODEC_ID_AAC &&
                        st->codecpar->extradata_size)
                        st->need_parsing = AVSTREAM_PARSE_NONE;
                    if (st->codecpar->codec_id == AV_CODEC_ID_FLAC)
                        st->need_parsing = AVSTREAM_PARSE_NONE;
                    /* AVI files with Xan DPCM audio (wrongly) declare PCM
                     * audio in the header but have Axan as stream_code_tag. */
                    if (ast->handler == AV_RL32("Axan")) {
                        st->codecpar->codec_id  = AV_CODEC_ID_XAN_DPCM;
                        st->codecpar->codec_tag = 0;
                        ast->dshow_block_align = 0;
                    }
                    if (amv_file_format) {
                        st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_IMA_AMV;
                        ast->dshow_block_align = 0;
                    }
                    if ((st->codecpar->codec_id == AV_CODEC_ID_AAC  ||
                         st->codecpar->codec_id == AV_CODEC_ID_FLAC ||
                         st->codecpar->codec_id == AV_CODEC_ID_MP2 ) && ast->dshow_block_align <= 4 && ast->dshow_block_align) {
                        av_log(s, AV_LOG_DEBUG, "overriding invalid dshow_block_align of %d\n", ast->dshow_block_align);
                        ast->dshow_block_align = 0;
                    }
                    if (st->codecpar->codec_id == AV_CODEC_ID_AAC && ast->dshow_block_align == 1024 && ast->sample_size == 1024 ||
                       st->codecpar->codec_id == AV_CODEC_ID_AAC && ast->dshow_block_align == 4096 && ast->sample_size == 4096 ||
                       st->codecpar->codec_id == AV_CODEC_ID_MP3 && ast->dshow_block_align == 1152 && ast->sample_size == 1152) {
                        av_log(s, AV_LOG_DEBUG, "overriding sample_size\n");
                        ast->sample_size = 0;
                    }
                    break;
                case AVMEDIA_TYPE_SUBTITLE:
                    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
                    st->request_probe= 1;
                    avio_skip(pb, size);
                    break;
                default:
                    st->codecpar->codec_type = AVMEDIA_TYPE_DATA;
                    st->codecpar->codec_id   = AV_CODEC_ID_NONE;
                    st->codecpar->codec_tag  = 0;
                    avio_skip(pb, size);
                    break;
                }
            }
            break;
        case MKTAG('s', 't', 'r', 'd'):
            if (stream_index >= (unsigned)s->nb_streams
                || s->streams[stream_index]->codecpar->extradata_size
                || s->streams[stream_index]->codecpar->codec_tag == MKTAG('H','2','6','4')) {
                avio_skip(pb, size);
            } else {
                uint64_t cur_pos = avio_tell(pb);
                if (cur_pos < list_end)
                    size = FFMIN(size, list_end - cur_pos);
                st = s->streams[stream_index];

                if (size<(1<<30)) {
                    if (st->codecpar->extradata) {
                        av_log(s, AV_LOG_WARNING, "New extradata in strd chunk, freeing previous one.\n");
                        av_freep(&st->codecpar->extradata);
                    }
                    if (ff_get_extradata(s, st->codecpar, pb, size) < 0)
                        return AVERROR(ENOMEM);
                }

                if (st->codecpar->extradata_size & 1) //FIXME check if the encoder really did this correctly
                    avio_r8(pb);

                ret = avi_extract_stream_metadata(s, st);
                if (ret < 0) {
                    av_log(s, AV_LOG_WARNING, "could not decoding EXIF data in stream header.\n");
                }
            }
            break;
        case MKTAG('i', 'n', 'd', 'x'):
            pos = avio_tell(pb);
            if ((pb->seekable & AVIO_SEEKABLE_NORMAL) && !(s->flags & AVFMT_FLAG_IGNIDX) &&
                avi->use_odml &&
                read_odml_index(s, 0) < 0 &&
                (s->error_recognition & AV_EF_EXPLODE))
                goto fail;
            avio_seek(pb, pos + size, SEEK_SET);
            break;
        case MKTAG('v', 'p', 'r', 'p'):
            if (stream_index < (unsigned)s->nb_streams && size > 9 * 4) {
                AVRational active, active_aspect;

                st = s->streams[stream_index];
                avio_rl32(pb);
                avio_rl32(pb);
                avio_rl32(pb);
                avio_rl32(pb);
                avio_rl32(pb);

                active_aspect.den = avio_rl16(pb);
                active_aspect.num = avio_rl16(pb);
                active.num        = avio_rl32(pb);
                active.den        = avio_rl32(pb);
                avio_rl32(pb); // nbFieldsPerFrame

                if (active_aspect.num && active_aspect.den &&
                    active.num && active.den) {
                    st->sample_aspect_ratio = av_div_q(active_aspect, active);
                    av_log(s, AV_LOG_TRACE, "vprp %d/%d %d/%d\n",
                            active_aspect.num, active_aspect.den,
                            active.num, active.den);
                }
                size -= 9 * 4;
            }
            avio_skip(pb, size);
            break;
        case MKTAG('s', 't', 'r', 'n'):
            if (s->nb_streams) {
                ret = avi_read_tag(s, s->streams[s->nb_streams - 1], tag, size);
                if (ret < 0)
                    return ret;
                break;
            }
        default:
            if (size > 1000000) {
                av_log(s, AV_LOG_ERROR,
                       "Something went wrong during header parsing, "
                       "tag %s has size %u, "
                       "I will ignore it and try to continue anyway.\n",
                       av_fourcc2str(tag), size);
                if (s->error_recognition & AV_EF_EXPLODE)
                    goto fail;
                avi->movi_list = avio_tell(pb) - 4;
                avi->movi_end  = avi->fsize;
                goto end_of_header;
            }
        /* Do not fail for very large idx1 tags */
        case MKTAG('i', 'd', 'x', '1'):
            /* skip tag */
            size += (size & 1);
            avio_skip(pb, size);
            break;
        }
    }

end_of_header:
    /* check stream number */
    if (stream_index != s->nb_streams - 1) {

fail:
        return AVERROR_INVALIDDATA;
    }

    if (!avi->index_loaded && (pb->seekable & AVIO_SEEKABLE_NORMAL))
        avi_load_index(s);
    calculate_bitrate(s);
    avi->index_loaded    |= 1;

    if ((ret = guess_ni_flag(s)) < 0)
        return ret;

    avi->non_interleaved |= ret | (s->flags & AVFMT_FLAG_SORT_DTS);

    dict_entry = av_dict_get(s->metadata, "ISFT", NULL, 0);
    if (dict_entry && !strcmp(dict_entry->value, "PotEncoder"))
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            if (   st->codecpar->codec_id == AV_CODEC_ID_MPEG1VIDEO
                || st->codecpar->codec_id == AV_CODEC_ID_MPEG2VIDEO)
                st->need_parsing = AVSTREAM_PARSE_FULL;
        }

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];
        if (st->nb_index_entries)
            break;
    }
    if (avi->dv_demux)
        avi->non_interleaved = 0;
    if (i == s->nb_streams && avi->non_interleaved) {
        av_log(s, AV_LOG_WARNING,
               "Non-interleaved AVI without index, switching to interleaved\n");
        avi->non_interleaved = 0;
    }

    if (avi->non_interleaved) {
        av_log(s, AV_LOG_INFO, "non-interleaved AVI\n");
        clean_index(s);
    }

    ff_metadata_conv_ctx(s, NULL, avi_metadata_conv);
    ff_metadata_conv_ctx(s, NULL, ff_riff_info_conv);

    return 0;
}

Project: FFmpeg

static int avi_read_idx1(AVFormatContext *s, int size)
{
    AVIContext *avi = s->priv_data;
    AVIOContext *pb = s->pb;
    int nb_index_entries, i;
    AVStream *st;
    AVIStream *ast;
    int64_t pos;
    unsigned int index, tag, flags, len, first_packet = 1;
    int64_t last_pos = -1;
    unsigned last_idx = -1;
    int64_t idx1_pos, first_packet_pos = 0, data_offset = 0;
    int anykey = 0;

    nb_index_entries = size / 16;
    if (nb_index_entries <= 0)
        return AVERROR_INVALIDDATA;

    idx1_pos = avio_tell(pb);
    avio_seek(pb, avi->movi_list + 4, SEEK_SET);
    if (avi_sync(s, 1) == 0)
        first_packet_pos = avio_tell(pb) - 8;
    avi->stream_index = -1;
    avio_seek(pb, idx1_pos, SEEK_SET);

    if (s->nb_streams == 1 && s->streams[0]->codecpar->codec_tag == AV_RL32("MMES")) {
        first_packet_pos = 0;
        data_offset = avi->movi_list;
    }

    /* Read the entries and sort them in each stream component. */
    for (i = 0; i < nb_index_entries; i++) {
        if (avio_feof(pb))
            return -1;

        tag   = avio_rl32(pb);
        flags = avio_rl32(pb);
        pos   = avio_rl32(pb);
        len   = avio_rl32(pb);
        av_log(s, AV_LOG_TRACE, "%d: tag=0x%x flags=0x%x pos=0x%"PRIx64" len=%d/",
                i, tag, flags, pos, len);

        index  = ((tag      & 0xff) - '0') * 10;
        index +=  (tag >> 8 & 0xff) - '0';
        if (index >= s->nb_streams)
            continue;
        st  = s->streams[index];
        ast = st->priv_data;

        /* Skip 'xxpc' palette change entries in the index until a logic
         * to process these is properly implemented. */
        if ((tag >> 16 & 0xff) == 'p' && (tag >> 24 & 0xff) == 'c')
            continue;

        if (first_packet && first_packet_pos) {
            if (avi->movi_list + 4 != pos || pos + 500 > first_packet_pos)
                data_offset  = first_packet_pos - pos;
            first_packet = 0;
        }
        pos += data_offset;

        av_log(s, AV_LOG_TRACE, "%d cum_len=%"PRId64"\n", len, ast->cum_len);

        if (last_pos == pos)
            avi->non_interleaved = 1;
        if (last_idx != pos && len) {
            av_add_index_entry(st, pos, ast->cum_len, len, 0,
                               (flags & AVIIF_INDEX) ? AVINDEX_KEYFRAME : 0);
            last_idx= pos;
        }
        ast->cum_len += get_duration(ast, len);
        last_pos      = pos;
        anykey       |= flags&AVIIF_INDEX;
    }
    if (!anykey) {
        for (index = 0; index < s->nb_streams; index++) {
            st = s->streams[index];
            if (st->nb_index_entries)
                st->index_entries[0].flags |= AVINDEX_KEYFRAME;
        }
    }
    return 0;
}

Project: FFmpeg

static void avi_read_nikon(AVFormatContext *s, uint64_t end)
{
    while (avio_tell(s->pb) < end && !avio_feof(s->pb)) {
        uint32_t tag  = avio_rl32(s->pb);
        uint32_t size = avio_rl32(s->pb);
        switch (tag) {
        case MKTAG('n', 'c', 't', 'g'):  /* Nikon Tags */
        {
            uint64_t tag_end = avio_tell(s->pb) + size;
            while (avio_tell(s->pb) < tag_end && !avio_feof(s->pb)) {
                uint16_t tag     = avio_rl16(s->pb);
                uint16_t size    = avio_rl16(s->pb);
                const char *name = NULL;
                char buffer[64]  = { 0 };
                size = FFMIN(size, tag_end - avio_tell(s->pb));
                size -= avio_read(s->pb, buffer,
                                  FFMIN(size, sizeof(buffer) - 1));
                switch (tag) {
                case 0x03:
                    name = "maker";
                    break;
                case 0x04:
                    name = "model";
                    break;
                case 0x13:
                    name = "creation_time";
                    if (buffer[4] == ':' && buffer[7] == ':')
                        buffer[4] = buffer[7] = '-';
                    break;
                }
                if (name)
                    av_dict_set(&s->metadata, name, buffer, 0);
                avio_skip(s->pb, size);
            }
            break;
        }
        default:
            avio_skip(s->pb, size);
            break;
        }
    }
}

Project: FFmpeg

static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    AVIContext *avi = s->priv_data;
    AVIOContext *pb = s->pb;
    int err;

    if (CONFIG_DV_DEMUXER && avi->dv_demux) {
        int size = avpriv_dv_get_packet(avi->dv_demux, pkt);
        if (size >= 0)
            return size;
        else
            goto resync;
    }

    if (avi->non_interleaved) {
        err = ni_prepare_read(s);
        if (err < 0)
            return err;
    }

resync:
    if (avi->stream_index >= 0) {
        AVStream *st   = s->streams[avi->stream_index];
        AVIStream *ast = st->priv_data;
        int size, err;

        if (get_subtitle_pkt(s, st, pkt))
            return 0;

        if (ast->sample_size <= 1)
            size = INT_MAX;
        else if (ast->sample_size < 32)
            size = 1024 * ast->sample_size;
        else
            size = ast->sample_size;

        if (size > ast->remaining)
            size = ast->remaining;
        avi->last_pkt_pos = avio_tell(pb);
        err               = av_get_packet(pb, pkt, size);
        if (err < 0)
            return err;
        size = err;

        if (ast->has_pal && pkt->size < (unsigned)INT_MAX / 2) {
            uint8_t *pal;
            pal = av_packet_new_side_data(pkt,
                                          AV_PKT_DATA_PALETTE,
                                          AVPALETTE_SIZE);
            if (!pal) {
                av_log(s, AV_LOG_ERROR,
                       "Failed to allocate data for palette\n");
            } else {
                memcpy(pal, ast->pal, AVPALETTE_SIZE);
                ast->has_pal = 0;
            }
        }

        if (CONFIG_DV_DEMUXER && avi->dv_demux) {
            AVBufferRef *avbuf = pkt->buf;
            size = avpriv_dv_produce_packet(avi->dv_demux, pkt,
                                            pkt->data, pkt->size, pkt->pos);
            pkt->buf    = avbuf;
            pkt->flags |= AV_PKT_FLAG_KEY;
            if (size < 0)
                av_packet_unref(pkt);
        } else if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE &&
                   !st->codecpar->codec_tag && read_gab2_sub(s, st, pkt)) {
            ast->frame_offset++;
            avi->stream_index = -1;
            ast->remaining    = 0;
            goto resync;
        } else {
            /* XXX: How to handle B-frames in AVI? */
            pkt->dts = ast->frame_offset;
            if (ast->sample_size)
                pkt->dts /= ast->sample_size;
            pkt->stream_index = avi->stream_index;

            if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && st->index_entries) {
                AVIndexEntry *e;
                int index;

                index = av_index_search_timestamp(st, ast->frame_offset, AVSEEK_FLAG_ANY);
                e     = &st->index_entries[index];

                if (index >= 0 && e->timestamp == ast->frame_offset) {
                    if (index == st->nb_index_entries-1) {
                        int key=1;
                        uint32_t state=-1;
                        if (st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
                            const uint8_t *ptr = pkt->data, *end = ptr + FFMIN(size, 256);
                            while (ptr < end) {
                                ptr = avpriv_find_start_code(ptr, end, &state);
                                if (state == 0x1B6 && ptr < end) {
                                    key = !(*ptr & 0xC0);
                                    break;
                                }
                            }
                        }
                        if (!key)
                            e->flags &= ~AVINDEX_KEYFRAME;
                    }
                    if (e->flags & AVINDEX_KEYFRAME)
                        pkt->flags |= AV_PKT_FLAG_KEY;
                }
            } else {
                pkt->flags |= AV_PKT_FLAG_KEY;
            }
            ast->frame_offset += get_duration(ast, pkt->size);
        }
        ast->remaining -= err;
        if (!ast->remaining) {
            avi->stream_index = -1;
            ast->packet_size  = 0;
        }

        if (!avi->non_interleaved && pkt->pos >= 0 && ast->seek_pos > pkt->pos) {
            av_packet_unref(pkt);
            goto resync;
        }
        ast->seek_pos= 0;

        if (!avi->non_interleaved && st->nb_index_entries>1 && avi->index_loaded>1) {
            int64_t dts= av_rescale_q(pkt->dts, st->time_base, AV_TIME_BASE_Q);

            if (avi->dts_max - dts > 2*AV_TIME_BASE) {
                avi->non_interleaved= 1;
                av_log(s, AV_LOG_INFO, "Switching to NI mode, due to poor interleaving\n");
            }else if (avi->dts_max < dts)
                avi->dts_max = dts;
        }

        return 0;
    }

    if ((err = avi_sync(s, 0)) < 0)
        return err;
    goto resync;
}

Project: FFmpeg

static int avi_read_seek(AVFormatContext *s, int stream_index,
                         int64_t timestamp, int flags)
{
    AVIContext *avi = s->priv_data;
    AVStream *st;
    int i, index;
    int64_t pos, pos_min;
    AVIStream *ast;

    /* Does not matter which stream is requested dv in avi has the
     * stream information in the first video stream.
     */
    if (avi->dv_demux)
        stream_index = 0;

    if (!avi->index_loaded) {
        /* we only load the index on demand */
        avi_load_index(s);
        avi->index_loaded |= 1;
    }
    av_assert0(stream_index >= 0);

    st    = s->streams[stream_index];
    ast   = st->priv_data;
    index = av_index_search_timestamp(st,
                                      timestamp * FFMAX(ast->sample_size, 1),
                                      flags);
    if (index < 0) {
        if (st->nb_index_entries > 0)
            av_log(s, AV_LOG_DEBUG, "Failed to find timestamp %"PRId64 " in index %"PRId64 " .. %"PRId64 "\n",
                   timestamp * FFMAX(ast->sample_size, 1),
                   st->index_entries[0].timestamp,
                   st->index_entries[st->nb_index_entries - 1].timestamp);
        return AVERROR_INVALIDDATA;
    }

    /* find the position */
    pos       = st->index_entries[index].pos;
    timestamp = st->index_entries[index].timestamp / FFMAX(ast->sample_size, 1);

    av_log(s, AV_LOG_TRACE, "XX %"PRId64" %d %"PRId64"\n",
            timestamp, index, st->index_entries[index].timestamp);

    if (CONFIG_DV_DEMUXER && avi->dv_demux) {
        /* One and only one real stream for DV in AVI, and it has video  */
        /* offsets. Calling with other stream indexes should have failed */
        /* the av_index_search_timestamp call above.                     */

        if (avio_seek(s->pb, pos, SEEK_SET) < 0)
            return -1;

        /* Feed the DV video stream version of the timestamp to the */
        /* DV demux so it can synthesize correct timestamps.        */
        ff_dv_offset_reset(avi->dv_demux, timestamp);

        avi->stream_index = -1;
        return 0;
    }

    pos_min = pos;
    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st2   = s->streams[i];
        AVIStream *ast2 = st2->priv_data;

        ast2->packet_size =
        ast2->remaining   = 0;

        if (ast2->sub_ctx) {
            seek_subtitle(st, st2, timestamp);
            continue;
        }

        if (st2->nb_index_entries <= 0)
            continue;

        index = av_index_search_timestamp(st2,
                                          av_rescale_q(timestamp,
                                                       st->time_base,
                                                       st2->time_base) *
                                          FFMAX(ast2->sample_size, 1),
                                          flags |
                                          AVSEEK_FLAG_BACKWARD |
                                          (st2->codecpar->codec_type != AVMEDIA_TYPE_VIDEO ? AVSEEK_FLAG_ANY : 0));
        if (index < 0)
            index = 0;
        ast2->seek_pos = st2->index_entries[index].pos;
        pos_min = FFMIN(pos_min,ast2->seek_pos);
    }
    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st2 = s->streams[i];
        AVIStream *ast2 = st2->priv_data;

        if (ast2->sub_ctx || st2->nb_index_entries <= 0)
            continue;

        index = av_index_search_timestamp(
                st2,
                av_rescale_q(timestamp, st->time_base, st2->time_base) * FFMAX(ast2->sample_size, 1),
                flags | AVSEEK_FLAG_BACKWARD | (st2->codecpar->codec_type != AVMEDIA_TYPE_VIDEO ? AVSEEK_FLAG_ANY : 0));
        if (index < 0)
            index = 0;
        while (!avi->non_interleaved && index>0 && st2->index_entries[index-1].pos >= pos_min)
            index--;
        ast2->frame_offset = st2->index_entries[index].timestamp;
    }

    /* do the seek */
    if (avio_seek(s->pb, pos_min, SEEK_SET) < 0) {
        av_log(s, AV_LOG_ERROR, "Seek failed\n");
        return -1;
    }
    avi->stream_index = -1;
    avi->dts_max      = INT_MIN;
    return 0;
}

Project: FFmpeg

static int avi_read_tag(AVFormatContext *s, AVStream *st, uint32_t tag,
                        uint32_t size)
{
    AVIOContext *pb = s->pb;
    char key[5]     = { 0 };
    char *value;

    size += (size & 1);

    if (size == UINT_MAX)
        return AVERROR(EINVAL);
    value = av_malloc(size + 1);
    if (!value)
        return AVERROR(ENOMEM);
    if (avio_read(pb, value, size) != size)
        return AVERROR_INVALIDDATA;
    value[size] = 0;

    AV_WL32(key, tag);

    return av_dict_set(st ? &st->metadata : &s->metadata, key, value,
                       AV_DICT_DONT_STRDUP_VAL);
}

Project: FFmpeg

static int avi_sync(AVFormatContext *s, int exit_early)
{
    AVIContext *avi = s->priv_data;
    AVIOContext *pb = s->pb;
    int n;
    unsigned int d[8];
    unsigned int size;
    int64_t i, sync;

start_sync:
    memset(d, -1, sizeof(d));
    for (i = sync = avio_tell(pb); !avio_feof(pb); i++) {
        int j;

        for (j = 0; j < 7; j++)
            d[j] = d[j + 1];
        d[7] = avio_r8(pb);

        size = d[4] + (d[5] << 8) + (d[6] << 16) + (d[7] << 24);

        n = get_stream_idx(d + 2);
        ff_tlog(s, "%X %X %X %X %X %X %X %X %"PRId64" %u %d\n",
                d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);
        if (i*(avi->io_fsize>0) + (uint64_t)size > avi->fsize || d[0] > 127)
            continue;

        if ((d[0] == 'i' && d[1] == 'x' && n < s->nb_streams) ||
            (d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K') ||
            (d[0] == 'i' && d[1] == 'd' && d[2] == 'x' && d[3] == '1') ||
            (d[0] == 'i' && d[1] == 'n' && d[2] == 'd' && d[3] == 'x')) {
            avio_skip(pb, size);
            goto start_sync;
        }

        if (d[0] == 'L' && d[1] == 'I' && d[2] == 'S' && d[3] == 'T') {
            avio_skip(pb, 4);
            goto start_sync;
        }

        n = get_stream_idx(d);

        if (!((i - avi->last_pkt_pos) & 1) &&
            get_stream_idx(d + 1) < s->nb_streams)
            continue;

        if (d[2] == 'i' && d[3] == 'x' && n < s->nb_streams) {
            avio_skip(pb, size);
            goto start_sync;
        }

        if (avi->dv_demux && n != 0)
            continue;

        if (n < s->nb_streams) {
            AVStream *st;
            AVIStream *ast;
            st  = s->streams[n];
            ast = st->priv_data;

            if (!ast) {
                av_log(s, AV_LOG_WARNING, "Skipping foreign stream %d packet\n", n);
                continue;
            }

            if (s->nb_streams >= 2) {
                AVStream *st1   = s->streams[1];
                AVIStream *ast1 = st1->priv_data;
                if (   d[2] == 'w' && d[3] == 'b'
                   && n == 0
                   && st ->codecpar->codec_type == AVMEDIA_TYPE_VIDEO
                   && st1->codecpar->codec_type == AVMEDIA_TYPE_AUDIO
                   && ast->prefix == 'd'*256+'c'
                   && (d[2]*256+d[3] == ast1->prefix || !ast1->prefix_count)
                  ) {
                    n   = 1;
                    st  = st1;
                    ast = ast1;
                    av_log(s, AV_LOG_WARNING,
                           "Invalid stream + prefix combination, assuming audio.\n");
                }
            }

            if (!avi->dv_demux &&
                ((st->discard >= AVDISCARD_DEFAULT && size == 0) /* ||
                 (st->discard >= AVDISCARD_NONKEY &&
                 !(pkt->flags & AV_PKT_FLAG_KEY)) */
                || st->discard >= AVDISCARD_ALL)) {
                if (!exit_early) {
                    ast->frame_offset += get_duration(ast, size);
                    avio_skip(pb, size);
                    goto start_sync;
                }
            }

            if (d[2] == 'p' && d[3] == 'c' && size <= 4 * 256 + 4) {
                int k    = avio_r8(pb);
                int last = (k + avio_r8(pb) - 1) & 0xFF;

                avio_rl16(pb); // flags

                for (; k <= last; k++)
                    ast->pal[k] = 0xFFU<<24 | avio_rb32(pb)>>8;

                ast->has_pal = 1;
                goto start_sync;
            } else if (((ast->prefix_count < 5 || sync + 9 > i) &&
                        d[2] < 128 && d[3] < 128) ||
                       d[2] * 256 + d[3] == ast->prefix /* ||
                       (d[2] == 'd' && d[3] == 'c') ||
                       (d[2] == 'w' && d[3] == 'b') */) {
                if (exit_early)
                    return 0;
                if (d[2] * 256 + d[3] == ast->prefix)
                    ast->prefix_count++;
                else {
                    ast->prefix       = d[2] * 256 + d[3];
                    ast->prefix_count = 0;
                }

                avi->stream_index = n;
                ast->packet_size  = size + 8;
                ast->remaining    = size;

                if (size) {
                    uint64_t pos = avio_tell(pb) - 8;
                    if (!st->index_entries || !st->nb_index_entries ||
                        st->index_entries[st->nb_index_entries - 1].pos < pos) {
                        av_add_index_entry(st, pos, ast->frame_offset, size,
                                           0, AVINDEX_KEYFRAME);
                    }
                }
                return 0;
            }
        }
    }

    if (pb->error)
        return pb->error;
    return AVERROR_EOF;
}

Project: FFmpeg

static int calculate_bitrate(AVFormatContext *s)
{
    AVIContext *avi = s->priv_data;
    int i, j;
    int64_t lensum = 0;
    int64_t maxpos = 0;

    for (i = 0; i<s->nb_streams; i++) {
        int64_t len = 0;
        AVStream *st = s->streams[i];

        if (!st->nb_index_entries)
            continue;

        for (j = 0; j < st->nb_index_entries; j++)
            len += st->index_entries[j].size;
        maxpos = FFMAX(maxpos, st->index_entries[j-1].pos);
        lensum += len;
    }
    if (maxpos < avi->io_fsize*9/10) // index does not cover the whole file
        return 0;
    if (lensum*9/10 > maxpos || lensum < maxpos*9/10) // frame sum and filesize mismatch
        return 0;

    for (i = 0; i<s->nb_streams; i++) {
        int64_t len = 0;
        AVStream *st = s->streams[i];
        int64_t duration;
        int64_t bitrate;

        for (j = 0; j < st->nb_index_entries; j++)
            len += st->index_entries[j].size;

        if (st->nb_index_entries < 2 || st->codecpar->bit_rate > 0)
            continue;
        duration = st->index_entries[j-1].timestamp - st->index_entries[0].timestamp;
        bitrate = av_rescale(8*len, st->time_base.den, duration * st->time_base.num);
        if (bitrate <= INT_MAX && bitrate > 0) {
            st->codecpar->bit_rate = bitrate;
        }
    }
    return 1;
}

Project: FFmpeg

static int check_stream_max_drift(AVFormatContext *s)
{
    int64_t min_pos, pos;
    int i;
    int *idx = av_mallocz_array(s->nb_streams, sizeof(*idx));
    if (!idx)
        return AVERROR(ENOMEM);
    for (min_pos = pos = 0; min_pos != INT64_MAX; pos = min_pos + 1LU) {
        int64_t max_dts = INT64_MIN / 2;
        int64_t min_dts = INT64_MAX / 2;
        int64_t max_buffer = 0;

        min_pos = INT64_MAX;

        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            AVIStream *ast = st->priv_data;
            int n = st->nb_index_entries;
            while (idx[i] < n && st->index_entries[idx[i]].pos < pos)
                idx[i]++;
            if (idx[i] < n) {
                int64_t dts;
                dts = av_rescale_q(st->index_entries[idx[i]].timestamp /
                                   FFMAX(ast->sample_size, 1),
                                   st->time_base, AV_TIME_BASE_Q);
                min_dts = FFMIN(min_dts, dts);
                min_pos = FFMIN(min_pos, st->index_entries[idx[i]].pos);
            }
        }
        for (i = 0; i < s->nb_streams; i++) {
            AVStream *st = s->streams[i];
            AVIStream *ast = st->priv_data;

            if (idx[i] && min_dts != INT64_MAX / 2) {
                int64_t dts;
                dts = av_rescale_q(st->index_entries[idx[i] - 1].timestamp /
                                   FFMAX(ast->sample_size, 1),
                                   st->time_base, AV_TIME_BASE_Q);
                max_dts = FFMAX(max_dts, dts);
                max_buffer = FFMAX(max_buffer,
                                   av_rescale(dts - min_dts,
                                              st->codecpar->bit_rate,
                                              AV_TIME_BASE));
            }
        }
        if (max_dts - min_dts > 2 * AV_TIME_BASE ||
            max_buffer > 1024 * 1024 * 8 * 8) {
            av_free(idx);
            return 1;
        }
    }
    av_free(idx);
    return 0;
}

Project: FFmpeg

static void clean_index(AVFormatContext *s)
{
    int i;
    int64_t j;

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st   = s->streams[i];
        AVIStream *ast = st->priv_data;
        int n          = st->nb_index_entries;
        int max        = ast->sample_size;
        int64_t pos, size, ts;

        if (n != 1 || ast->sample_size == 0)
            continue;

        while (max < 1024)
            max += max;

        pos  = st->index_entries[0].pos;
        size = st->index_entries[0].size;
        ts   = st->index_entries[0].timestamp;

        for (j = 0; j < size; j += max)
            av_add_index_entry(st, pos + j, ts + j, FFMIN(max, size - j), 0,
                               AVINDEX_KEYFRAME);
    }
}

Project: FFmpeg

static inline int get_duration(AVIStream *ast, int len)
{
    if (ast->sample_size)
        return len;
    else if (ast->dshow_block_align)
        return (len + ast->dshow_block_align - 1) / ast->dshow_block_align;
    else
        return 1;
}

Project: FFmpeg

static int get_riff(AVFormatContext *s, AVIOContext *pb)
{
    AVIContext *avi = s->priv_data;
    char header[8] = {0};
    int i;

    /* check RIFF header */
    avio_read(pb, header, 4);
    avi->riff_end  = avio_rl32(pb); /* RIFF chunk size */
    avi->riff_end += avio_tell(pb); /* RIFF chunk end */
    avio_read(pb, header + 4, 4);

    for (i = 0; avi_headers[i][0]; i++)
        if (!memcmp(header, avi_headers[i], 8))
            break;
    if (!avi_headers[i][0])
        return AVERROR_INVALIDDATA;

    if (header[7] == 0x19)
        av_log(s, AV_LOG_INFO,
               "This file has been generated by a totally broken muxer.\n");

    return 0;
}

Project: FFmpeg

static int get_stream_idx(const unsigned *d)
{
    if (d[0] >= '0' && d[0] <= '9' &&
        d[1] >= '0' && d[1] <= '9') {
        return (d[0] - '0') * 10 + (d[1] - '0');
    } else {
        return 100; // invalid stream ID
    }
}

Project: FFmpeg

static int guess_ni_flag(AVFormatContext *s)
{
    int i;
    int64_t last_start = 0;
    int64_t first_end  = INT64_MAX;
    int64_t oldpos     = avio_tell(s->pb);

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];
        int n        = st->nb_index_entries;
        unsigned int size;

        if (n <= 0)
            continue;

        if (n >= 2) {
            int64_t pos = st->index_entries[0].pos;
            unsigned tag[2];
            avio_seek(s->pb, pos, SEEK_SET);
            tag[0] = avio_r8(s->pb);
            tag[1] = avio_r8(s->pb);
            avio_rl16(s->pb);
            size = avio_rl32(s->pb);
            if (get_stream_idx(tag) == i && pos + size > st->index_entries[1].pos)
                last_start = INT64_MAX;
            if (get_stream_idx(tag) == i && size == st->index_entries[0].size + 8)
                last_start = INT64_MAX;
        }

        if (st->index_entries[0].pos > last_start)
            last_start = st->index_entries[0].pos;
        if (st->index_entries[n - 1].pos < first_end)
            first_end = st->index_entries[n - 1].pos;
    }
    avio_seek(s->pb, oldpos, SEEK_SET);

    if (last_start > first_end)
        return 1;

    return check_stream_max_drift(s);
}

Project: FFmpeg

static int ni_prepare_read(AVFormatContext *s)
{
    AVIContext *avi = s->priv_data;
    int best_stream_index = 0;
    AVStream *best_st     = NULL;
    AVIStream *best_ast;
    int64_t best_ts = INT64_MAX;
    int i;

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st   = s->streams[i];
        AVIStream *ast = st->priv_data;
        int64_t ts     = ast->frame_offset;
        int64_t last_ts;

        if (!st->nb_index_entries)
            continue;

        last_ts = st->index_entries[st->nb_index_entries - 1].timestamp;
        if (!ast->remaining && ts > last_ts)
            continue;

        ts = av_rescale_q(ts, st->time_base,
                          (AVRational) { FFMAX(1, ast->sample_size),
                                         AV_TIME_BASE });

        av_log(s, AV_LOG_TRACE, "%"PRId64" %d/%d %"PRId64"\n", ts,
                st->time_base.num, st->time_base.den, ast->frame_offset);
        if (ts < best_ts) {
            best_ts           = ts;
            best_st           = st;
            best_stream_index = i;
        }
    }
    if (!best_st)
        return AVERROR_EOF;

    best_ast = best_st->priv_data;
    best_ts  = best_ast->frame_offset;
    if (best_ast->remaining) {
        i = av_index_search_timestamp(best_st,
                                      best_ts,
                                      AVSEEK_FLAG_ANY |
                                      AVSEEK_FLAG_BACKWARD);
    } else {
        i = av_index_search_timestamp(best_st, best_ts, AVSEEK_FLAG_ANY);
        if (i >= 0)
            best_ast->frame_offset = best_st->index_entries[i].timestamp;
    }

    if (i >= 0) {
        int64_t pos = best_st->index_entries[i].pos;
        pos += best_ast->packet_size - best_ast->remaining;
        if (avio_seek(s->pb, pos + 8, SEEK_SET) < 0)
          return AVERROR_EOF;

        av_assert0(best_ast->remaining <= best_ast->packet_size);

        avi->stream_index = best_stream_index;
        if (!best_ast->remaining)
            best_ast->packet_size =
            best_ast->remaining   = best_st->index_entries[i].size;
    }
    else
        return AVERROR_EOF;

    return 0;
}

Project: FFmpeg

static int read_odml_index(AVFormatContext *s, int frame_num)
{
    AVIContext *avi     = s->priv_data;
    AVIOContext *pb     = s->pb;
    int longs_per_entry = avio_rl16(pb);
    int index_sub_type  = avio_r8(pb);
    int index_type      = avio_r8(pb);
    int entries_in_use  = avio_rl32(pb);
    int chunk_id        = avio_rl32(pb);
    int64_t base        = avio_rl64(pb);
    int stream_id       = ((chunk_id      & 0xFF) - '0') * 10 +
                          ((chunk_id >> 8 & 0xFF) - '0');
    AVStream *st;
    AVIStream *ast;
    int i;
    int64_t last_pos = -1;
    int64_t filesize = avi->fsize;

    av_log(s, AV_LOG_TRACE,
            "longs_per_entry:%d index_type:%d entries_in_use:%d "
            "chunk_id:%X base:%16"PRIX64" frame_num:%d\n",
            longs_per_entry,
            index_type,
            entries_in_use,
            chunk_id,
            base,
            frame_num);

    if (stream_id >= s->nb_streams || stream_id < 0)
        return AVERROR_INVALIDDATA;
    st  = s->streams[stream_id];
    ast = st->priv_data;

    if (index_sub_type)
        return AVERROR_INVALIDDATA;

    avio_rl32(pb);

    if (index_type && longs_per_entry != 2)
        return AVERROR_INVALIDDATA;
    if (index_type > 1)
        return AVERROR_INVALIDDATA;

    if (filesize > 0 && base >= filesize) {
        av_log(s, AV_LOG_ERROR, "ODML index invalid\n");
        if (base >> 32 == (base & 0xFFFFFFFF) &&
            (base & 0xFFFFFFFF) < filesize    &&
            filesize <= 0xFFFFFFFF)
            base &= 0xFFFFFFFF;
        else
            return AVERROR_INVALIDDATA;
    }

    for (i = 0; i < entries_in_use; i++) {
        if (index_type) {
            int64_t pos = avio_rl32(pb) + base - 8;
            int len     = avio_rl32(pb);
            int key     = len >= 0;
            len &= 0x7FFFFFFF;

            av_log(s, AV_LOG_TRACE, "pos:%"PRId64", len:%X\n", pos, len);

            if (avio_feof(pb))
                return AVERROR_INVALIDDATA;

            if (last_pos == pos || pos == base - 8)
                avi->non_interleaved = 1;
            if (last_pos != pos && len)
                av_add_index_entry(st, pos, ast->cum_len, len, 0,
                                   key ? AVINDEX_KEYFRAME : 0);

            ast->cum_len += get_duration(ast, len);
            last_pos      = pos;
        } else {
            int64_t offset, pos;
            int duration;
            offset = avio_rl64(pb);
            avio_rl32(pb);       /* size */
            duration = avio_rl32(pb);

            if (avio_feof(pb))
                return AVERROR_INVALIDDATA;

            pos = avio_tell(pb);

            if (avi->odml_depth > MAX_ODML_DEPTH) {
                av_log(s, AV_LOG_ERROR, "Too deeply nested ODML indexes\n");
                return AVERROR_INVALIDDATA;
            }

            if (avio_seek(pb, offset + 8, SEEK_SET) < 0)
                return -1;
            avi->odml_depth++;
            read_odml_index(s, frame_num);
            avi->odml_depth--;
            frame_num += duration;

            if (avio_seek(pb, pos, SEEK_SET) < 0) {
                av_log(s, AV_LOG_ERROR, "Failed to restore position after reading index\n");
                return -1;
            }

        }
    }
    avi->index_loaded = 2;
    return 0;
}

Project: FFmpeg

static void seek_subtitle(AVStream *st, AVStream *st2, int64_t timestamp)
{
    AVIStream *ast2 = st2->priv_data;
    int64_t ts2     = av_rescale_q(timestamp, st->time_base, st2->time_base);
    av_packet_unref(&ast2->sub_pkt);
    if (avformat_seek_file(ast2->sub_ctx, 0, INT64_MIN, ts2, ts2, 0) >= 0 ||
        avformat_seek_file(ast2->sub_ctx, 0, ts2, ts2, INT64_MAX, 0) >= 0)
        ff_read_packet(ast2->sub_ctx, &ast2->sub_pkt);
}