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authorLeo Izen <leo.izen@gmail.com>2023-03-21 23:26:26 -0400
committerLeo Izen <leo.izen@gmail.com>2023-04-01 00:37:55 -0400
commitc125860892e931d9b10f88ace73c91484815c3a8 (patch)
treef6e4941ee42a4009d43ee8aed46c96348b160b8c
parent84b454935fae2633a8a5dd075e22393f3e8f932f (diff)
avcodec/pngenc: write sBIT chunks
Add support for writing sBIT chunks, which mark the significant bit depth of the PNG file. This obtains the metadata using the field bits_per_raw_sample of AVCodecContext. Signed-off-by: Leo Izen <leo.izen@gmail.com>
-rw-r--r--libavcodec/pngenc.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 1489256d00..21b033ea16 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -442,6 +442,12 @@ static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
if (png_get_gama(pict->color_trc, s->buf))
png_write_chunk(&s->bytestream, MKTAG('g', 'A', 'M', 'A'), s->buf, 4);
+ if (avctx->bits_per_raw_sample > 0 && avctx->bits_per_raw_sample < s->bit_depth) {
+ int len = ff_png_get_nb_channels(s->color_type);
+ memset(s->buf, avctx->bits_per_raw_sample, len);
+ png_write_chunk(&s->bytestream, MKTAG('s', 'B', 'I', 'T'), s->buf, len);
+ }
+
/* put the palette if needed, must be after colorspace information */
if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
int has_alpha, alpha, i;