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mirror of https://git.videolan.org/git/ffmpeg.git synced 2024-09-01 22:16:42 +02:00

avcodec/pngdec: do not blend on transparent black

There is no need to memset the zlib output buffer, as there is no
blending happening there. Instead, do not blend when the dispose
operation is set to 'background' (tranparent black).

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Benoit Fouet 2014-11-28 10:43:01 +01:00 committed by Michael Niedermayer
parent bd67d0ead1
commit aff50ae1d1

View File

@ -674,10 +674,6 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
s->crow_buf = s->buffer + 15;
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
if (avctx->codec_id == AV_CODEC_ID_APNG &&
s->dispose_op == APNG_DISPOSE_OP_BACKGROUND)
memset(s->zstream.next_out, 0, s->zstream.avail_out);
}
s->state |= PNG_IDAT;
if ((ret = png_decode_idat(s, length)) < 0)
@ -887,7 +883,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
pd_last += s->image_linesize;
}
if (s->blend_op == APNG_BLEND_OP_OVER) {
if (s->dispose_op != APNG_DISPOSE_OP_BACKGROUND && s->blend_op == APNG_BLEND_OP_OVER) {
uint8_t ri, gi, bi, ai;
if (avctx->pix_fmt == AV_PIX_FMT_RGBA) {