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avcodec/apng: Add blending support for non-alpha pixel formats

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Signed-off-by: Donny Yang <work@kota.moe>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Donny Yang 2015-06-02 15:49:25 +00:00 committed by Michael Niedermayer
parent ed09bb3782
commit 0ab1c46fe0
1 changed files with 15 additions and 0 deletions
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15
libavcodec/pngdec.c
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@ -58,6 +58,7 @@ typedef struct PNGDecContext {
int channels; int channels;
int bits_per_pixel; int bits_per_pixel;
int bpp; int bpp;
int has_trns;
uint8_t *image_buf; uint8_t *image_buf;
int image_linesize; int image_linesize;
@ -732,6 +733,8 @@ static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s,
} }
bytestream2_skip(&s->gb, 4); /* crc */ bytestream2_skip(&s->gb, 4); /* crc */
s->has_trns = 1;
return 0; return 0;
} }
@ -848,6 +851,18 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
s->dispose_op = APNG_DISPOSE_OP_BACKGROUND; s->dispose_op = APNG_DISPOSE_OP_BACKGROUND;
} }
if (s->dispose_op == APNG_BLEND_OP_OVER && !s->has_trns && (
avctx->pix_fmt == AV_PIX_FMT_RGB24 ||
avctx->pix_fmt == AV_PIX_FMT_RGB48BE ||
avctx->pix_fmt == AV_PIX_FMT_PAL8 ||
avctx->pix_fmt == AV_PIX_FMT_GRAY8 ||
avctx->pix_fmt == AV_PIX_FMT_GRAY16BE ||
avctx->pix_fmt == AV_PIX_FMT_MONOBLACK
)) {
// APNG_DISPOSE_OP_OVER is the same as APNG_DISPOSE_OP_SOURCE when there is no alpha channel
s->dispose_op = APNG_BLEND_OP_SOURCE;
}
return 0; return 0;
} }