Niklas Haas (12023-12-14): > From: Niklas Haas <g...@haasn.dev> > > Currently, the logic inside the FF_FILTER_FORMATS_QUERY_FUNC branch > prevents this code from running in the event that we have a filter with > a single video input and a single audio output, as the resulting audio > output link will not have its channel counts / samplerates correctly > initialized to their default values, possibly triggering a segfault > downstream. > > An example of such a filter is vaf_spectrumsynth. Although this > particular filter already sets up the channel counts and samplerates as > part of the query function and therefore avoids triggering this bug, the > bug still exists in principle. (And importantly, sets a wrong precedent) > --- > libavfilter/formats.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-)
You are asking the framework to guess the audio format when it has NOTHING to base its guess on. This is a terrible idea. When a filter has no audio input but must produce audio, only the filter itself knows what kind of audio it will produce, and it should say so in query_formats(). What happens in spectrumsynth is what MUST happens. It is not a wrong precedent, it is the proper way of things. The worry that a filter will forget to do so and result in a segfault seems wrong to me: just testing the filter before committing would reveal it, not even regression testing is necessary. But if you really want, I would not object to a consistency check after the call to query_formats(). Regards, -- Nicolas George _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
