On Fri, May 9, 2025 at 11:38 PM Andrew Randrianasulu < [email protected]> wrote:
> I was looking at why our application (cinelerra-gg) crashed at trying to > use libplacebo > > I found that libplacebo defines itself > > https://ffmpeg.org/doxygen/7.0/vf__libplacebo_8c.html > > as > > .flags = AVFILTER_FLAG_HWDEVICE > <https://ffmpeg.org/doxygen/7.0/group__lavfi.html#ga01e3b7175b4477235061256f3398eecc> > | AVFILTER_FLAG_DYNAMIC_INPUTS > <https://ffmpeg.org/doxygen/7.0/group__lavfi.html#gae6ed6c10a03508829bdf17560e3e10e5> > , > > so only output pad is defined, as far as I can see: > > static const AVFilterPad > <https://ffmpeg.org/doxygen/7.0/structAVFilterPad.html> libplacebo_outputs > <https://ffmpeg.org/doxygen/7.0/vf__libplacebo_8c.html#a3545e8f08cc238430300b27efc10cdaf>[] > = { > { > .name > <https://ffmpeg.org/doxygen/7.0/structAVFilterPad.html#afc112061a6035639934e0135aab7d425> > = "default", > .type = AVMEDIA_TYPE_VIDEO > <https://ffmpeg.org/doxygen/7.0/group__lavu__misc.html#gga9a84bba4713dfced21a1a56163be1f48ac1a46f59be5c6c2d3412ab172d6b8cf5> > , > .config_props = &libplacebo_config_output > <https://ffmpeg.org/doxygen/7.0/vf__libplacebo_8c.html#a09a97380118a876bb5fce38315c70f6a> > , > }, > }; > > > > then when our code calls > > avfilter_pad_get_type() > You need to call it only after filtergraph have been configured, not before because in such cases number of output pads may be 0 before configuration. In any case you need to check current number of input pads and output pads for each filter before trying to access them. > > it promptly crashes. > > BC_Signals::dump_stack > cin() [0x8b2c9e2] > linux-gate.so.1(__kernel_rt_sigreturn+0) [0xf7fb8590] > cin(avfilter_pad_get_type+0x14) [0x99266a4] > cin(_ZN13FFVideoStream13create_filterEPKc+0xbc) [0x865669c] > cin(_ZN6FFMPEG12open_decoderEv+0x80f) [0x865732f] > cin(_ZN10FileFFMPEG9check_sigEP5Asset+0x81) [0x8670071] > cin(_ZN4File5probeEv+0x376) [0x867cd86] > cin(_ZN4File9open_fileEP11PreferencesP5Assetii+0x378) [0x867d628] > cin(_ZN7MWindow14load_filenamesEP9ArrayListIPcEiii+0x250) [0x87301f0] > cin(_ZN17CommandLineThread3runEv+0x53) [0x86e2cd3] > cin(_ZN6Thread10entrypointEPv+0x41) [0x8b70c11] > /lib/libpthread.so.0(+0x7328) [0xf7df9328] > /lib/libc.so.6(clone+0x66) [0xf0373f06] > > > > We still hope to get libplacebo's tonemapping + vulkan hevc decoding > going, so any pointers how to talk to those dynamic_input filters will be > useful. Even swscale is dynamic_input in ffmpeg 7.1+, so I (we) really hope > to keep it working, too. > > Code: > > > https://git.cinelerra-gg.org/git/?p=goodguy/cinelerra.git;a=blob;f=cinelerra-5.1/cinelerra/ffmpeg.C;h=1d0979df59f932628246678a920aca002d8dd88b;hb=HEAD#l3893 > > > > _______________________________________________ > Libav-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/libav-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". >
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