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<p>Commit <a moz-do-not-send="true"
href="https://github.com/FFmpeg/FFmpeg/commit/3f9137c57d2344d7613f134128235c18edcede95">3f9137c
</a>changed how avfilter behaved in my application and I was
wondering if it is a FFmpeg bug, my bug, or intended behavior?</p>
<p>My application reads in media with avfilter/avcodec, resizes it
with swscale, applies an overlay with avfilter, swscales it again,
then encodes it with libjpeg-turbo. If I don't set AVFrame::pts to
AV_NOPTS_VALUE before giving it to avfilter, I get a <a
moz-do-not-send="true"
href="https://abex.sauville.org/ffmpeg_garbage/garbage%20at%20bottom.jpg">blank
frame with some garbage at the bottom</a>. Additionally this
only happens with <a moz-do-not-send="true"
href="https://abex.sauville.org/ffmpeg_garbage/rawpng.png">some
PNG inputs</a>(afaik, haven't tried many formats). This does not
happen with h264 in a mp4, or with a <a moz-do-not-send="true"
href="https://abex.sauville.org/ffmpeg_garbage/png_in_mp3.mp3">PNG
in a mp3</a>. In this configuration only one frame goes through
the filter before it is destroyed. <br>
</p>
<p>Relevant code in my application is here:<a moz-do-not-send="true"
href="https://bitbucket.org/Abex/yumeko/src/3960c8e03f2e69a329b1074ba6bda7fb2b08c112/thumblink/mutators/thumbnailer/base.go?fileviewer=file-view-default#base.go-393"><br>
base.go</a><br>
<a moz-do-not-send="true"
href="https://bitbucket.org/Abex/yumeko/src/3960c8e03f2e69a329b1074ba6bda7fb2b08c112/ffmpeg/format.h?fileviewer=file-view-default">format.h</a><br>
<a moz-do-not-send="true"
href="https://bitbucket.org/Abex/yumeko/src/3960c8e03f2e69a329b1074ba6bda7fb2b08c112/ffmpeg/format.go?at=master&fileviewer=file-view-default">format.go</a><br>
</p>
<p>Unfortunately this code does not lend itself to debugging very
well, due to tight integration, lack of testing, and FFI borders,
so if this does look like a bug, I can try to get a smaller repro
if that would help. <br>
</p>
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