[FFmpeg-devel] [PATCH] avfilter/vf_xcam: add xcam video filter

[Paul B Mahol]

On 7/31/20, Zong, Wei <wei.zong at intel.com> wrote:
>
>
>> -----Original Message-----
>> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Paul B
>> Mahol
>> Sent: Friday, July 31, 2020 3:57 PM
>> To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
>> Cc: Liu, YinhangX <yinhangx.liu at intel.com>
>> Subject: Re: [FFmpeg-devel] [PATCH] avfilter/vf_xcam: add xcam video
>> filter
>>
>> On 7/31/20, Zong, Wei <wei.zong at intel.com> wrote:
>> > Thank you for the comments on this patch, I want to make some
>> > explanation on your comments.
>> >
>> > 1. the purpose of this patch
>> >      We got some requirements from users who are trying libxcam
>> > stitching or developers who showing interests. Many of them want an
>> > easy way to construct an end 2 end pipeline of high quality immersive
>> > media
>> application.
>> >     The key points are high resolution and low latency, FFMpeg
>> > provides high quality video codec framework, if we implement video
>> > stitching as a video filter in FFMpeg, they will get benefits.
>> >
>> > 2. 3rd party dependency
>> >     The functions exposed by xcam filter only depends on essential
>> > build tool-chain.
>> > According to hardware configuration, user can get performance
>> > improvement by install OCL, GLES or Vulkan.
>> > These libraries are not necessary for video stitching, user can build
>> > a CPU version without these libraries.
>> >     Beside these, stitching and DVS function depend on feature match
>> > algorithm from OpenCV library to get better quality, I posted demo
>> > link in commit message.
>> > User can run stitching without install OpenCV, the side effect is the
>> > quality will decrease.
>> >
>> > 3. Immersive media standard
>> >     Normally the camera manufactures provide video stitching software,
>> > they defined private camera calibration parameters, these are very
>> > critical to stitching quality. I know MPEG is making proposal on
>> > transfer these meta-data in video stream, this will help compose
>> > immersive media on cloud or edge server. I think it's a good idea to
>> > create such a video filter in FFMpeg pipeline.
>> >
>> > 4. Why not implement stitching inside FFMpeg video filter
>> >     The algorithms are complexity and the performance are also
>> > important, the stitching function manage computing resource for
>> > example thread handling, image data block dispatching. Personally I
>> > think we don't need to construct a wheel from the beginning.
>>
>> Number of supported pixel formats are rather very low.
>
>    Do you mean the pixel format (NV12 & YUV420) that xcam filter supported
> is not enough?
>  xcam filter works as a post processing component between video decoder and
> encoder, we suppose the data comes from camera or stored video clips, so it
> handles YUV format.
> libxcam algorithm optimization highly depends on pixel layout, to support
> YUV422 or YUV444 will cost much effort, we do not meet the requirement till
> now.

Ok then, I thought library provided support for it already.

Supporting only few pixel formats is very limited functionality IMHO.

>
>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel at ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request at ffmpeg.org
>> with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".