fre 2023-02-17 klockan 10:12 +0000 skrev Nicolas Gaullier: > > The logic here is a bit hairy and I don't have time atm to digest > > it, but is it entirely contained in S337m or would one need to read > > other specs too? > > > > /Tomas > > ff_s337m_probe is very similar to s337m_probe: what mainly differs is > the input parameters. > The one little thing I added is the S337M_PROBE_GUARDBAND_MIN_BYTES. > Currently it is set to 0, so has no effect (and of course I can > remove it if someone object). > There is two things to know about it: > - one is that some DolbyE decoder implementations does not support > the s337m sync word to be the first word, > A minimal guard band (full of zero) is required in such a case : 1 > word is enough in the cases I experimented. > One developer might find it useful to set > S337M_PROBE_GUARDBAND_MIN_BYTES to 1 in order to ffprobe-qc/reject > such files. > - one other thing is that, currently, the detection is based on 3 > consecutive samples, > But there are other implementations in the wild. A common single- > sample implementation is to simply require > a sufficient S337M_PROBE_GUARDBAND_MIN_BYTES in order to avoid a fake > detection. > (for 16 bits, this is really dangerous!; for 24 bits, I think it is > fair but would still require some little additions to be 100% sure).
What a mess.. And there's no other way to reliably probe this? /Tomas _______________________________________________ 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".
