static int mjpegb_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; MJpegDecodeContext *s = avctx->priv_data; const uint8_t *buf_end, *buf_ptr; AVFrame *picture = data; GetBitContext hgb; /* for the header */ uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs; uint32_t field_size, sod_offs; buf_ptr = buf; buf_end = buf + buf_size; read_header: /* reset on every SOI */ s->restart_interval = 0; s->restart_count = 0; s->mjpb_skiptosod = 0; if (buf_end - buf_ptr >= 1 << 28) return AVERROR_INVALIDDATA; init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8); skip_bits(&hgb, 32); /* reserved zeros */ if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g')) { av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n"); return 0; } field_size = get_bits_long(&hgb, 32); /* field size */ av_log(avctx, AV_LOG_DEBUG, "field size: 0x%x\n", field_size); skip_bits(&hgb, 32); /* padded field size */ second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%x\n", second_field_offs); dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%x\n", dqt_offs); if (dqt_offs) { init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8); s->start_code = DQT; if (ff_mjpeg_decode_dqt(s) < 0 && (avctx->err_recognition & AV_EF_EXPLODE)) return AVERROR_INVALIDDATA; } dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%x\n", dht_offs); if (dht_offs) { init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8); s->start_code = DHT; ff_mjpeg_decode_dht(s); } sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%x\n", sof_offs); if (sof_offs) { init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8); s->start_code = SOF0; if (ff_mjpeg_decode_sof(s) < 0) return -1; } sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%x\n", sos_offs); sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%x\n", sod_offs); if (sos_offs) { init_get_bits(&s->gb, buf_ptr + sos_offs, 8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs)); s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16)); s->start_code = SOS; if (ff_mjpeg_decode_sos(s, NULL, NULL) < 0 && (avctx->err_recognition & AV_EF_EXPLODE)) return AVERROR_INVALIDDATA; } if (s->interlaced) { s->bottom_field ^= 1; /* if not bottom field, do not output image yet */ if (s->bottom_field != s->interlace_polarity && second_field_offs) { buf_ptr = buf + second_field_offs; second_field_offs = 0; goto read_header; } } //XXX FIXME factorize, this looks very similar to the EOI code *picture= *s->picture_ptr; *data_size = sizeof(AVFrame); if(!s->lossless){ picture->quality= FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2]); picture->qstride= 0; picture->qscale_table= s->qscale_table; memset(picture->qscale_table, picture->quality, (s->width+15)/16); if(avctx->debug & FF_DEBUG_QP) av_log(avctx, AV_LOG_DEBUG, "QP: %d\n", picture->quality); picture->quality*= FF_QP2LAMBDA; } return buf_ptr - buf; }
static int mjpegb_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; MJpegDecodeContext *s = avctx->priv_data; const uint8_t *buf_end, *buf_ptr; AVFrame *picture = data; GetBitContext hgb;   uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs; uint32_t field_size, sod_offs; buf_ptr = buf; buf_end = buf + buf_size; read_header:   s->restart_interval = 0; s->restart_count = 0; s->mjpb_skiptosod = 0; if (buf_end - buf_ptr >= 1 << 28) return AVERROR_INVALIDDATA; init_get_bits(&hgb, buf_ptr,  (buf_end - buf_ptr)*8); skip_bits(&hgb, 32);   if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g')) { av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n"); return 0; } field_size = get_bits_long(&hgb, 32);   av_log(avctx, AV_LOG_DEBUG, "field size: 0x%x\n", field_size); skip_bits(&hgb, 32);   second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%x\n", second_field_offs); dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%x\n", dqt_offs); if (dqt_offs) { init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8); s->start_code = DQT; if (ff_mjpeg_decode_dqt(s) < 0 && (avctx->err_recognition & AV_EF_EXPLODE)) return AVERROR_INVALIDDATA; } dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%x\n", dht_offs); if (dht_offs) { init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8); s->start_code = DHT; ff_mjpeg_decode_dht(s); } sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%x\n", sof_offs); if (sof_offs) { init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8); s->start_code = SOF0; if (ff_mjpeg_decode_sof(s) < 0) return -1; } sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%x\n", sos_offs); sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n"); av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%x\n", sod_offs); if (sos_offs) { init_get_bits(&s->gb, buf_ptr + sos_offs, 8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs)); s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16)); s->start_code = SOS; if (ff_mjpeg_decode_sos(s, NULL, NULL) < 0 && (avctx->err_recognition & AV_EF_EXPLODE)) return AVERROR_INVALIDDATA; } if (s->interlaced) { s->bottom_field ^= 1;   if (s->bottom_field != s->interlace_polarity && second_field_offs) { buf_ptr = buf + second_field_offs; second_field_offs = 0; goto read_header; } }  