High color 15-bit VQA3 video streams contain high level chunks with only codebook updates that shouldn't be considered new frames. Now the demuxer stores a reference to such VQFL chunks and returns them later along with a VQFR chunk with full frame data. --- libavformat/westwood_vqa.c | 49 ++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-)
diff --git a/libavformat/westwood_vqa.c b/libavformat/westwood_vqa.c index 77df007c11..587626ea67 100644 --- a/libavformat/westwood_vqa.c +++ b/libavformat/westwood_vqa.c @@ -1,6 +1,7 @@ /* * Westwood Studios VQA Format Demuxer - * Copyright (c) 2003 The FFmpeg project + * Copyright (c) 2003 Mike Melanson <melan...@pcisys.net> + * Copyright (c) 2021 Pekka Väänänen <pekka.vaana...@iki.fi> * * This file is part of FFmpeg. * @@ -40,6 +41,7 @@ #define SND1_TAG MKBETAG('S', 'N', 'D', '1') #define SND2_TAG MKBETAG('S', 'N', 'D', '2') #define VQFR_TAG MKBETAG('V', 'Q', 'F', 'R') +#define VQFL_TAG MKBETAG('V', 'Q', 'F', 'L') /* don't know what these tags are for, but acknowledge their existence */ #define CINF_TAG MKBETAG('C', 'I', 'N', 'F') @@ -60,6 +62,8 @@ typedef struct WsVqaDemuxContext { int sample_rate; int audio_stream_index; int video_stream_index; + int64_t vqfl_chunk_pos; + int vqfl_chunk_size; } WsVqaDemuxContext; static int wsvqa_probe(const AVProbeData *p) @@ -120,6 +124,8 @@ static int wsvqa_read_header(AVFormatContext *s) wsvqa->channels = header[26]; wsvqa->bps = header[27]; wsvqa->audio_stream_index = -1; + wsvqa->vqfl_chunk_pos = 0; + wsvqa->vqfl_chunk_size = 0; s->ctx_flags |= AVFMTCTX_NOHEADER; @@ -172,11 +178,21 @@ static int wsvqa_read_packet(AVFormatContext *s, skip_byte = chunk_size & 0x01; - if ((chunk_type == SND0_TAG) || (chunk_type == SND1_TAG) || + if (chunk_type == VQFL_TAG) { + /* Each VQFL chunk carries only a codebook update inside which must be applied + * before the next VQFR is rendered. That's why we stash the VQFL offset here + * so it can be combined with the next VQFR packet. This way each packet + * includes a whole frame as expected. */ + wsvqa->vqfl_chunk_pos = avio_tell(pb); + wsvqa->vqfl_chunk_size = (int)chunk_size; + avio_skip(pb, chunk_size + skip_byte); + continue; + } else if ((chunk_type == SND0_TAG) || (chunk_type == SND1_TAG) || (chunk_type == SND2_TAG) || (chunk_type == VQFR_TAG)) { - ret= av_get_packet(pb, pkt, chunk_size); - if (ret<0) + ret = av_get_packet(pb, pkt, chunk_size); + + if (ret < 0) return AVERROR(EIO); switch (chunk_type) { @@ -235,6 +251,31 @@ static int wsvqa_read_packet(AVFormatContext *s, } break; case VQFR_TAG: + /* if a new codebook is available inside an earlier a VQFL chunk then + * prepend it to 'pkt' */ + if (wsvqa->vqfl_chunk_size > 0) { + int64_t current_pos = pkt->pos; + int current_size = pkt->size; + + if (avio_seek(pb, wsvqa->vqfl_chunk_pos, SEEK_SET) < 0) + return AVERROR(EIO); + + /* the decoder expects chunks to be 16-bit aligned */ + if (wsvqa->vqfl_chunk_size % 2 == 1) + wsvqa->vqfl_chunk_size++; + + if (av_get_packet(pb, pkt, wsvqa->vqfl_chunk_size) < 0) + return AVERROR(EIO); + + if (avio_seek(pb, current_pos, SEEK_SET) < 0) + return AVERROR(EIO); + + ret = av_append_packet(pb, pkt, current_size); + + wsvqa->vqfl_chunk_pos = 0; + wsvqa->vqfl_chunk_size = 0; + } + pkt->stream_index = wsvqa->video_stream_index; pkt->duration = 1; break; -- 2.25.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".