On Sun, Oct 4, 2015 at 10:16 PM, Michael Niedermayer <michae...@gmx.at> wrote: > On Sun, Oct 04, 2015 at 09:21:55PM -0400, Ganesh Ajjanagadde wrote: >> Fixes CID 1322359, CID 1322358. >> >> Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com> >> --- >> libavcodec/pngdec.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c >> index d180141..fe22225 100644 >> --- a/libavcodec/pngdec.c >> +++ b/libavcodec/pngdec.c >> @@ -1006,7 +1006,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, >> PNGDecContext *s, >> uint8_t *background = buffer + s->image_linesize * y + s->bpp * >> s->x_offset; >> for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, >> foreground += s->bpp, background += s->bpp) { >> size_t b; >> - uint8_t foreground_alpha, background_alpha, output_alpha; >> + uint8_t foreground_alpha = 0, background_alpha, >> output_alpha; > > this looks very odd > have you checked that the reference png implementation and png spec > set foreground_alpha to 0 for cases that FFmpeg doesnt implement ? ;) > > warnings can point to bugs and if so the bug should be fixed which > should make the warning disappear. If a warning doesnt point to a bug > then it should be silenced in some clean way > > It seems you try to silence this one without really realizing > what is wrong with the codepath in which this warning occurs
I did not look at this deeply. Furthermore, I assumed that the Coverity scan does not report false positives. More precisely, I assumed (incorrectly) that when Coverity says a code path is reached, etc it is based on an actual runtime input or a guaranteed static analysis, and not simply on some heuristics. Good to know for future use of Coverity. > > I didnt write it but to me it seems the if() a few lines above is > intended to stop this codepath > see 'avpriv_request_sample(avctx, "Blending with pixel format %s",' Looking at this more carefully I agree with you, and so I drop this patch. > > it doesnt work as blend_op is assumed to have only 2 values but > this is not checked for anywhere. > blend_op should be checked when/before it is set > > > [...] > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > I do not agree with what you have to say, but I'll defend to the death your > right to say it. -- Voltaire > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel