static int xwma_read_header(AVFormatContext *s) { int64_t size; int ret = 0; uint32_t dpds_table_size = 0; uint32_t *dpds_table = NULL; unsigned int tag; AVIOContext *pb = s->pb; AVStream *st; XWMAContext *xwma = s->priv_data; int i; /* The following code is mostly copied from wav.c, with some * minor alterations. */ /* check RIFF header */ tag = avio_rl32(pb); if (tag != MKTAG('R', 'I', 'F', 'F')) return -1; avio_rl32(pb); /* file size */ tag = avio_rl32(pb); if (tag != MKTAG('X', 'W', 'M', 'A')) return -1; /* parse fmt header */ tag = avio_rl32(pb); if (tag != MKTAG('f', 'm', 't', ' ')) return -1; size = avio_rl32(pb); st = avformat_new_stream(s, NULL); if (!st) return AVERROR(ENOMEM); ret = ff_get_wav_header(pb, st->codec, size, 0); if (ret < 0) return ret; st->need_parsing = AVSTREAM_PARSE_NONE; /* All xWMA files I have seen contained WMAv2 data. If there are files * using WMA Pro or some other codec, then we need to figure out the right * extradata for that. Thus, ask the user for feedback, but try to go on * anyway. */ if (st->codec->codec_id != AV_CODEC_ID_WMAV2) { avpriv_request_sample(s, "Unexpected codec (tag 0x04%x; id %d)", st->codec->codec_tag, st->codec->codec_id); } else { /* In all xWMA files I have seen, there is no extradata. But the WMA * codecs require extradata, so we provide our own fake extradata. * * First, check that there really was no extradata in the header. If * there was, then try to use it, after asking the user to provide a * sample of this unusual file. */ if (st->codec->extradata_size != 0) { /* Surprise, surprise: We *did* get some extradata. No idea * if it will work, but just go on and try it, after asking * the user for a sample. */ avpriv_request_sample(s, "Unexpected extradata (%d bytes)", st->codec->extradata_size); } else { st->codec->extradata_size = 6; st->codec->extradata = av_mallocz(6 + FF_INPUT_BUFFER_PADDING_SIZE); if (!st->codec->extradata) return AVERROR(ENOMEM); /* setup extradata with our experimentally obtained value */ st->codec->extradata[4] = 31; } } if (!st->codec->channels) { av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n", st->codec->channels); return AVERROR_INVALIDDATA; } if (!st->codec->bits_per_coded_sample) { av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n", st->codec->bits_per_coded_sample); return AVERROR_INVALIDDATA; } /* set the sample rate */ avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate); /* parse the remaining RIFF chunks */ for (;;) { if (pb->eof_reached) { ret = AVERROR_EOF; goto fail; } /* read next chunk tag */ tag = avio_rl32(pb); size = avio_rl32(pb); if (tag == MKTAG('d', 'a', 't', 'a')) { /* We assume that the data chunk comes last. */ break; } else if (tag == MKTAG('d','p','d','s')) { /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the * decoded packet cumulative data size array, each element is the * number of bytes accumulated after the corresponding xWMA packet * is decoded in order." * * Each packet has size equal to st->codec->block_align, which in * all cases I saw so far was always 2230. Thus, we can use the * dpds data to compute a seeking index. */ /* Error out if there is more than one dpds chunk. */ if (dpds_table) { av_log(s, AV_LOG_ERROR, "two dpds chunks present\n"); ret = AVERROR_INVALIDDATA; goto fail; } /* Compute the number of entries in the dpds chunk. */ if (size & 3) { /* Size should be divisible by four */ av_log(s, AV_LOG_WARNING, "dpds chunk size %"PRId64" not divisible by 4\n", size); } dpds_table_size = size / 4; if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) { av_log(s, AV_LOG_ERROR, "dpds chunk size %"PRId64" invalid\n", size); return AVERROR_INVALIDDATA; } /* Allocate some temporary storage to keep the dpds data around. * for processing later on. */ dpds_table = av_malloc(dpds_table_size * sizeof(uint32_t)); if (!dpds_table) { return AVERROR(ENOMEM); } for (i = 0; i < dpds_table_size; ++i) { dpds_table[i] = avio_rl32(pb); size -= 4; } } avio_skip(pb, size); } /* Determine overall data length */ if (size < 0) { ret = AVERROR_INVALIDDATA; goto fail; } if (!size) { xwma->data_end = INT64_MAX; } else xwma->data_end = avio_tell(pb) + size; if (dpds_table && dpds_table_size) { int64_t cur_pos; const uint32_t bytes_per_sample = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3; /* Estimate the duration from the total number of output bytes. */ const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1]; if (!bytes_per_sample) { av_log(s, AV_LOG_ERROR, "Invalid bits_per_coded_sample %d for %d channels\n", st->codec->bits_per_coded_sample, st->codec->channels); ret = AVERROR_INVALIDDATA; goto fail; } st->duration = total_decoded_bytes / bytes_per_sample; /* Use the dpds data to build a seek table. We can only do this after * we know the offset to the data chunk, as we need that to determine * the actual offset to each input block. * Note: If we allowed ourselves to assume that the data chunk always * follows immediately after the dpds block, we could of course guess * the data block's start offset already while reading the dpds chunk. * I decided against that, just in case other chunks ever are * discovered. */ cur_pos = avio_tell(pb); for (i = 0; i < dpds_table_size; ++i) { /* From the number of output bytes that would accumulate in the * output buffer after decoding the first (i+1) packets, we compute * an offset / timestamp pair. */ av_add_index_entry(st, cur_pos + (i+1) * st->codec->block_align, /* pos */ dpds_table[i] / bytes_per_sample, /* timestamp */ st->codec->block_align, /* size */ 0, /* duration */ AVINDEX_KEYFRAME); } } else if (st->codec->bit_rate) { /* No dpds chunk was present (or only an empty one), so estimate * the total duration using the average bits per sample and the * total data length. */ st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate; } fail: av_free(dpds_table); return ret; }
static int xwma_read_header(AVFormatContext *s) { int64_t size; int ret = 0; uint32_t dpds_table_size = 0; uint32_t *dpds_table = NULL; unsigned int tag; AVIOContext *pb = s->pb; AVStream *st; XWMAContext *xwma = s->priv_data; int i;     tag = avio_rl32(pb); if (tag != MKTAG('R', 'I', 'F', 'F')) return -1; avio_rl32(pb);   tag = avio_rl32(pb); if (tag != MKTAG('X', 'W', 'M', 'A')) return -1;   tag = avio_rl32(pb); if (tag != MKTAG('f', 'm', 't', ' ')) return -1; size = avio_rl32(pb); st = avformat_new_stream(s, NULL); if (!st) return AVERROR(ENOMEM); ret = ff_get_wav_header(pb, st->codec, size, 0); if (ret < 0) return ret; st->need_parsing = AVSTREAM_PARSE_NONE;   if (st->codec->codec_id != AV_CODEC_ID_WMAV2) { avpriv_request_sample(s, "Unexpected codec (tag 0x04%x; id %d)", st->codec->codec_tag, st->codec->codec_id); } else {   if (st->codec->extradata_size != 0) {   avpriv_request_sample(s, "Unexpected extradata (%d bytes)", st->codec->extradata_size); } else { st->codec->extradata_size = 6; st->codec->extradata = av_mallocz(6 + FF_INPUT_BUFFER_PADDING_SIZE); if (!st->codec->extradata) return AVERROR(ENOMEM);   st->codec->extradata[4] = 31; } } if (!st->codec->channels) { av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n", st->codec->channels); return AVERROR_INVALIDDATA; } if (!st->codec->bits_per_coded_sample) { av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n", st->codec->bits_per_coded_sample); return AVERROR_INVALIDDATA; }   avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);   for (;;) { if (pb->eof_reached) { ret = AVERROR_EOF; goto fail; }   tag = avio_rl32(pb); size = avio_rl32(pb); if (tag == MKTAG('d', 'a', 't', 'a')) {   break; } else if (tag == MKTAG('d','p','d','s')) {     if (dpds_table) { av_log(s, AV_LOG_ERROR, "two dpds chunks present\n"); ret = AVERROR_INVALIDDATA; goto fail; }   if (size & 3) {   av_log(s, AV_LOG_WARNING, "dpds chunk size %"PRId64" not divisible by 4\n", size); } dpds_table_size = size / 4; if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) { av_log(s, AV_LOG_ERROR, "dpds chunk size %"PRId64" invalid\n", size); return AVERROR_INVALIDDATA; }   dpds_table = av_malloc(dpds_table_size * sizeof(uint32_t)); if (!dpds_table) { return AVERROR(ENOMEM); } for (i = 0; i < dpds_table_size; ++i) { dpds_table[i] = avio_rl32(pb); size -= 4; } } avio_skip(pb, size); }   if (size < 0) { ret = AVERROR_INVALIDDATA; goto fail; } if (!size) { xwma->data_end = INT64_MAX; } else xwma->data_end = avio_tell(pb) + size; if (dpds_table && dpds_table_size) { int64_t cur_pos; const uint32_t bytes_per_sample = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3;   const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1]; if (!bytes_per_sample) { av_log(s, AV_LOG_ERROR, "Invalid bits_per_coded_sample %d for %d channels\n", st->codec->bits_per_coded_sample, st->codec->channels); ret = AVERROR_INVALIDDATA; goto fail; } st->duration = total_decoded_bytes / bytes_per_sample;   cur_pos = avio_tell(pb); for (i = 0; i < dpds_table_size; ++i) {   av_add_index_entry(st, cur_pos + (i+1) * st->codec->block_align,   dpds_table[i] / bytes_per_sample,   st->codec->block_align,   0,   AVINDEX_KEYFRAME); } } else if (st->codec->bit_rate) {   st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate; } fail: av_free(dpds_table); return ret; }