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avformat/westwood_vqa: Store VQFL codebook chunks

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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.
This commit is contained in:
Pekka Väänänen 2021-09-22 15:42:23 +03:00 committed by Paul B Mahol
parent 844890b1bc
commit 4d52e36bd0
1 changed files with 46 additions and 2 deletions
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48
libavformat/westwood_vqa.c
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@ -1,6 +1,7 @@
/*
* Westwood Studios VQA Format Demuxer
* Copyright (c) 2003 The FFmpeg project
* Copyright (c) 2003 Mike Melanson <melanson@pcisys.net>
* Copyright (c) 2021 Pekka Väänänen <pekka.vaananen@iki.fi>
*
* This file is part of FFmpeg.
*
@ -30,6 +31,7 @@
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#define FORM_TAG MKBETAG('F', 'O', 'R', 'M')
@ -40,6 +42,7 @@
#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 +63,8 @@ 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 +125,8 @@ 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;
@ -172,7 +179,22 @@ 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);
if (wsvqa->vqfl_chunk_size < 0 || wsvqa->vqfl_chunk_size > 3 * (1 << 20))
return AVERROR_INVALIDDATA;
/* We need a big seekback buffer because there can be SNxx, VIEW and ZBUF
* chunks (<512 KiB total) in the stream before we read VQFR (<256 KiB) and
* seek back here. */
ffio_ensure_seekback(pb, wsvqa->vqfl_chunk_size + (512 + 256) * 1024);
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);
@ -235,6 +257,28 @@ static int wsvqa_read_packet(AVFormatContext *s,
}
break;
case VQFR_TAG:
/* if a new codebook is available inside an earlier a VQFL chunk then
* append it to 'pkt' */
if (wsvqa->vqfl_chunk_size > 0) {
int64_t current_pos = pkt->pos;
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_append_packet(pb, pkt, wsvqa->vqfl_chunk_size) < 0)
return AVERROR(EIO);
if (avio_seek(pb, current_pos, SEEK_SET) < 0)
return AVERROR(EIO);
wsvqa->vqfl_chunk_pos = 0;
wsvqa->vqfl_chunk_size = 0;
}
pkt->stream_index = wsvqa->video_stream_index;
pkt->duration = 1;
break;