[FFmpeg-devel] ffmpeg_vdpau: Re-add ability to ignore level check

Mark Thompson sw at jkqxz.net
Wed Jun 8 15:54:58 CEST 2016

On 08/06/16 13:59, Carl Eugen Hoyos wrote:
> Mark Thompson <sw <at> jkqxz.net> writes:
>> Uses the global -hwaccel_lax_profile_check option (may be 
>> misnamed for this purpose, but it has the right spirit).
> Iirc, all old x264 files have a very high profile set (5.0?).
> Is there a usecase for the default not being to accept any 
> profile?

(You mean level rather than profile there, right?)

The point here is that the driver has declared its capabilities, and the given
stream is not within those capabilities so the hwaccel should not be used
because it will not work (the software decoder should be used instead, which
will supports a wider set of streams).  However, in reality we have known cases
where the driver is broken and incorrectly reports this information, and can in
fact decode some streams which it has stated it is unable to.

Now, obviously fixing the driver to correctly report capabilities would be the
way to actually fix the problem, but we don't control that.  This option allows
the user to ignore the declared capabilities of the driver and attempt decode
anyway - it may then fail, but the user did explicitly request it so if it
doesn't work then it is their problem.  Setting it by default would result in
some streams which previously worked now unexpectedly failing, which would be
worse than the current situation.

I hope that was clearer.


- Mark

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