[vlc-devel] [PATCH] avcodec: only disable frame threading if DXVA2 is likely to be used

[Steve Lhomme]

Never mind, I've had the buffer lock issue with a HEVC sample. So
avcodec still can't pick the right threading module by itself. Or
we're not handling the buffers the way it wants...

On Wed, Apr 1, 2015 at 2:11 PM, Steve Lhomme <robux4 at videolabs.io> wrote:
> On Wed, Apr 1, 2015 at 1:27 PM, Rémi Denis-Courmont <remi at remlab.net> wrote:
>> Le 2015-03-31 13:16, Steve Lhomme a écrit :
>>>
>>> Fixes #14054
>>
>>
>> This will leave threading enabled if the video track starts with an
>> hardware-unsupported profile, then downgrades to a hardware-supported
>> profile (e.g. due to new H.264 SPS). If DxVA2 is compatible with threading,
>> then you should remove the whole ifdef. If DxVA2 is not compatible with
>> threading, then the patch is wrong.
>
> The file of this issue that introduced the change is working for me in
> frame threading.
> https://trac.videolan.org/vlc/ticket/11930
>
> It didn't originally work on a Surface Pro 1 but it could be worth if
> it's working without the change, now that the code has been
> cleaned/optimized a little.
>
> poke j-b or Thomas Nigro.
>
>>> ---
>>>  modules/codec/avcodec/video.c | 7 +++----
>>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/modules/codec/avcodec/video.c b/modules/codec/avcodec/video.c
>>> index 381fe62..379bc62 100644
>>> --- a/modules/codec/avcodec/video.c
>>> +++ b/modules/codec/avcodec/video.c
>>> @@ -396,19 +396,18 @@ int InitVideoDec( decoder_t *p_dec,
>>> AVCodecContext *p_context,
>>>              break;
>>>      }
>>>
>>> +# if defined(_WIN32)
>>>      /* Workaround: frame multithreading is not compatible with
>>>       * DXVA2. When a frame is being copied to host memory, the frame
>>>       * is locked and cannot be used as a reference frame
>>>       * simultaneously and thus decoding fails for some frames. This
>>>       * causes major image corruption. */
>>> -# if defined(_WIN32)
>>> -    char *avcodec_hw = var_InheritString( p_dec, "avcodec-hw" );
>>> -    if( avcodec_hw == NULL || strcasecmp( avcodec_hw, "none" ) )
>>> +    enum PixelFormat test_formats[] = { AV_PIX_FMT_DXVA2_VLD,
>>> AV_PIX_FMT_NONE };
>>> +    if( AV_PIX_FMT_DXVA2_VLD == ffmpeg_GetFormat( p_context,
>>> &test_formats ) )
>>>      {
>>>          msg_Warn( p_dec, "threaded frame decoding is not compatible
>>> with DXVA2, disabled" );
>>>          p_context->thread_type &= ~FF_THREAD_FRAME;
>>>      }
>>> -    free( avcodec_hw );
>>>  # endif
>>>
>>>      if( p_context->thread_type & FF_THREAD_FRAME )
>>
>>
>> --
>> Rémi Denis-Courmont
>>
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