[FFmpeg-devel] hevc_probe won't recognize stream

Michael Niedermayer michaelni at gmx.at
Wed Jan 14 18:11:08 CET 2015

On Wed, Jan 14, 2015 at 06:04:15PM +0100, Ståle Kristoffersen wrote:
> I have a TS-file, which I unfortunately can't share, that contains only one
> PID, and that is a 4K HEVC-video stream at around 30Mbps.
> This file is from the middle of a broadcast and thus it do not start
> cleanly.
> ffmpeg is not able to detect that the file is HEVC, and falls back to AAC
> (with a score of 1), see [1].
> I have tried to increase -probesize, but that does not seem to make any
> difference.
> After digging around I found that for hevc_probe to detect a stream it must
> see at least the following NALs: "VPS", "SPS", "PPS" and "IRAP". My file
> does not have thos NALs in the first 2.5 MB of the file, and it seems the
> probe gives up after RAW_PACKET_BUFFER_SIZE (2500000) bytes.
> Increasing that and recompiling makes ffmpeg work fine.
> What is the correct approach for fixing this?

Make hevc_probe() return a higher score than 1 for this kind of cut
stream while minimizing the chances that something thats not hevc
is triggering that higher score

also see tools/probetest

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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