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avcodec/pngenc: write cLLi and mDVc chunks 

These chunks contain the Content Light Level Information and the
Mastering Display Color Volume information that FFmpeg already supports
as AVFrameSideData. This patch adds support for the png encoder to save
this metadata as the corresponding chunks in the PNG stream.

Signed-off-by: Leo Izen <leo.izen@gmail.com>
This commit is contained in:
Leo Izen 2024-02-04 04:35:58 -05:00
parent c7a57b0f70
commit 7894904141
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GPG Key ID: 764E48EA48221833
1 changed files with 29 additions and 3 deletions
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32
libavcodec/pngenc.c
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@ -32,6 +32,7 @@
#include "libavutil/crc.h"
#include "libavutil/csp.h"
#include "libavutil/libm.h"
#include "libavutil/mastering_display_metadata.h"
#include "libavutil/opt.h"
#include "libavutil/rational.h"
#include "libavutil/stereo3d.h"
@ -294,8 +295,9 @@ static int png_write_row(AVCodecContext *avctx, const uint8_t *data, int size)
return 0;
}
#define AV_WB32_PNG(buf, n) AV_WB32(buf, lrint((n) * 100000))
#define AV_WB32_PNG_D(buf, d) AV_WB32_PNG(buf, av_q2d(d))
#define PNG_LRINT(d, divisor) lrint((d) * (divisor))
#define PNG_Q2D(q, divisor) PNG_LRINT(av_q2d(q), (divisor))
#define AV_WB32_PNG_D(buf, q) AV_WB32(buf, PNG_Q2D(q, 100000))
static int png_get_chrm(enum AVColorPrimaries prim, uint8_t *buf)
{
const AVColorPrimariesDesc *desc = av_csp_primaries_desc_from_id(prim);
@ -320,7 +322,7 @@ static int png_get_gama(enum AVColorTransferCharacteristic trc, uint8_t *buf)
if (gamma <= 1e-6)
return 0;
AV_WB32_PNG(buf, 1.0 / gamma);
AV_WB32(buf, PNG_LRINT(1.0 / gamma, 100000));
return 1;
}
@ -437,6 +439,30 @@ static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
png_write_chunk(&s->bytestream, MKTAG('c', 'I', 'C', 'P'), s->buf, 4);
}
side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL);
if (side_data) {
AVContentLightMetadata *clli = (AVContentLightMetadata *) side_data->data;
AV_WB32(s->buf, clli->MaxCLL * 10000);
AV_WB32(s->buf + 4, clli->MaxFALL * 10000);
png_write_chunk(&s->bytestream, MKTAG('c', 'L', 'L', 'i'), s->buf, 8);
}
side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_MASTERING_DISPLAY_METADATA);
if (side_data) {
AVMasteringDisplayMetadata *mdvc = (AVMasteringDisplayMetadata *) side_data->data;
if (mdvc->has_luminance && mdvc->has_primaries) {
for (int i = 0; i < 3; i++) {
AV_WB16(s->buf + 2*i, PNG_Q2D(mdvc->display_primaries[i][0], 50000));
AV_WB16(s->buf + 2*i + 2, PNG_Q2D(mdvc->display_primaries[i][1], 50000));
}
AV_WB16(s->buf + 12, PNG_Q2D(mdvc->white_point[0], 50000));
AV_WB16(s->buf + 14, PNG_Q2D(mdvc->white_point[1], 50000));
AV_WB32(s->buf + 16, PNG_Q2D(mdvc->max_luminance, 10000));
AV_WB32(s->buf + 20, PNG_Q2D(mdvc->min_luminance, 10000));
png_write_chunk(&s->bytestream, MKTAG('m', 'D', 'V', 'c'), s->buf, 24);
}
}
if (png_get_chrm(pict->color_primaries, s->buf))
png_write_chunk(&s->bytestream, MKTAG('c', 'H', 'R', 'M'), s->buf, 32);
if (png_get_gama(pict->color_trc, s->buf))