[FFmpeg-devel] [PATCH 1/5] lavc : yami : add libyami decoder/encoder

[Jun Zhao]

On 2016/8/16 10:14, Chao Liu wrote:
> On Mon, Aug 15, 2016 at 6:00 PM, Jun Zhao <mypopydev at gmail.com> wrote:
> 
>>
>>
>> On 2016/8/16 1:48, Jean-Baptiste Kempf wrote:
>>> On 15 Aug, Hendrik Leppkes wrote :
>>>>> On Mon, Aug 15, 2016 at 10:22 AM, Jun Zhao <mypopydev at gmail.com>
>> wrote:
>>>>>>> add libyami decoder/encoder/vpp in ffmpeg, about build step,
>>>>>>> please refer to the link: https://github.com/01org/
>> ffmpeg_libyami/wiki/Build
>>>>>>>
>>>>>
>>>>> We've had patches for yami before, and they were not applied because
>>>>> many developers did not agree with adding more wrappers for the same
>>>>> hardware decoders which we already support.
>>>>> Please refer to the discussion in this thread:
>>>>> https://ffmpeg.org/pipermail/ffmpeg-devel/2015-January/167388.html
>>>>>
>>>>> The concerns and reasons brought up there should not really have
>> changed.
>>> I still object very strongly against yami.
>>>
>>> It is a library that does not bring much that we could not do ourselves,
>>> it duplicates a lot of our code, it is the wrong level of abstraction
>>> for libavcodec, it is using a bad license and there is no guarantee of
>>> maintainership in the future.
>>
>> I know the worry after read the above thread.For Intel GPU HW accelerate
>> decode/encode,
>> now have 3 options in ffmpeg:
>>
>> 1. ffmpeg and QSV (Media SDK)
>> 2. ffmpeg vaapi hw accelerate decoder/native vaapi encoder
>> 3. ffmpeg and libyami
>>
> Sorry for this little diversion: what are the differences between QSV and
> vaapi?
> My understanding is that QSV has better performance, while vaapi supports
> more decoders / encoders. Is that correct?
> It would be nice if there are some data showing the speed of these HW
> accelerated decoders / encoders.

QSV has better performance is right, but libyami have more decoders/encoders than 
vaapi hw accel decoder/encoder. :)

According our profile, the speed of QSV/Libyami/vaapi-hw accel decoder and native
vaapi encoder are: QSV > ffmpeg and libyami > vaapi-hw accel decoder and native
vaapi encoder

> 
>>
>> And I know the guys prefer option 2 than 3, but I have a little question,
>> what's the
>> difference about ffmpeg/libyami and the other external codec library(e,g
>> openh264,
>> videotoolbox...)?
>>
> Is 2 available in ffmpeg today or is it sth. planned?
> 

Option 2 is available today :), I think the wiki page ( https://wiki.libav.org/Hardware/vaapi) 
is good refer to for option 2, if you want to try. :)

>>
>> As I know Intel have 3 full time Libyami developers, so no guarantee maybe
>> is wrong.:)
>>
>> Tks.
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>>
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