[FFmpeg-devel] ffmpeg stuck in transcoding H264 using QSV

[Chao Liu]

On Tue, Jul 26, 2016 at 2:08 AM, Ivan Uskov <ivan.uskov at nablet.com> wrote:

>
> Hello Chao,
>
> Tuesday, July 26, 2016, 9:04:49 AM, you wrote:
>
> > I tried to debug it a bit by comparing ffmpeg code with intel media SDK.
> > There is sth. I don't understand. Not sure whether it's related..
> > In ffmpeg, we decode the frame in a loop
> > <https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/qsvdec.c#L357>,
> it
> > sleeps and retries as long as MFXVideoDECODE_DecodeFrameAsync returns
> busy.
> > In intel media SDK sample_decode, it calls SyncOperation when
> > MFXVideoDECODE_DecodeFrameAsync returns busy.
>
> > Could this be the cause?
> The documentation for MFXVideoDECODE_DecodeFrameAsync says:
> =========
> MFX_WRN_DEVICE_BUSY
> Hardware device is currently busy. Call this function again in a few
> milliseconds.
> =========
> So if documented way does not work it looks like we have issue inside SDK.
> But I will try to double check sample_decode code.
>
> By the way, what is your platform? Linux? Do you use a patched kernel
> recommended by Intel for specific sdk version?
>
You are right. It seems to be caused by the kernel.
It works well on Intel's golden CentOS 7.1 (3.10.0-229 with patches)
The same code and environment doesn't work on Ubuntu 16.04 (4.4.0)
I'll ask help on Intel forum. Thanks.

>
>
> --
> Best regards,
>  Ivan                            mailto:ivan.uskov at nablet.com
>
>