static int film_read_packet(AVFormatContext *s, AVPacket *pkt) { FilmDemuxContext *film = s->priv_data; AVIOContext *pb = s->pb; film_sample *sample; int ret = 0; int i; int left, right; if (film->current_sample >= film->sample_count) sample = &film->sample_table[film->current_sample]; /* position the stream (will probably be there anyway) */ avio_seek(pb, sample->sample_offset, SEEK_SET); /* do a special song and dance when loading FILM Cinepak chunks */ if ((sample->stream == film->video_stream_index) && (film->video_type == CODEC_ID_CINEPAK)) { pkt->pos= avio_tell(pb); if (av_new_packet(pkt, sample->sample_size)) return AVERROR(ENOMEM); avio_read(pb, pkt->data, sample->sample_size); } else if ((sample->stream == film->audio_stream_index) && (film->audio_channels == 2) && (film->audio_type != CODEC_ID_ADPCM_ADX)) { /* stereo PCM needs to be interleaved */ if (av_new_packet(pkt, sample->sample_size)) return AVERROR(ENOMEM); /* make sure the interleave buffer is large enough */ if (sample->sample_size > film->stereo_buffer_size) { av_free(film->stereo_buffer); film->stereo_buffer_size = sample->sample_size; film->stereo_buffer = av_malloc(film->stereo_buffer_size); if (!film->stereo_buffer) { film->stereo_buffer_size = 0; return AVERROR(ENOMEM); } } pkt->pos= avio_tell(pb); ret = avio_read(pb, film->stereo_buffer, sample->sample_size); if (ret != sample->sample_size) ret = AVERROR(EIO); left = 0; right = sample->sample_size / 2; for (i = 0; i < sample->sample_size; ) { if (film->audio_bits == 8) { pkt->data[i++] = film->stereo_buffer[left++]; pkt->data[i++] = film->stereo_buffer[right++]; } else { pkt->data[i++] = film->stereo_buffer[left++]; pkt->data[i++] = film->stereo_buffer[left++]; pkt->data[i++] = film->stereo_buffer[right++]; pkt->data[i++] = film->stereo_buffer[right++]; } } } else { ret= av_get_packet(pb, pkt, sample->sample_size); if (ret != sample->sample_size) ret = AVERROR(EIO); } pkt->stream_index = sample->stream; pkt->pts = sample->pts; film->current_sample++; return ret; }