The xcam filter is providing high quality stitching, accepting data from the current 360 camera, one example is: https://www.insta360.com/product/insta360-pro2/. Now the current 360 camera output doesn't provide a broad pixel format, only YUV420P and NV12. (For other formats, we can use current FFmpeg filters to handle with a little performance and quality drop.) Beside this, this xcam filter can work with FFmpeg's v360 filter together, one example is transforming the stitching result from ERP (res:7680x3840) to CubeMap (res:5760x3840), this can save 50% bitrate.
Paul B Mahol <one...@gmail.com> 于2020年7月31日周五 下午4:39写道： > On 7/31/20, Zong, Wei <wei.z...@intel.com> wrote: > > > > > >> -----Original Message----- > >> From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of Paul > B > >> Mahol > >> Sent: Friday, July 31, 2020 3:57 PM > >> To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org > > > >> Cc: Liu, YinhangX <yinhangx....@intel.com> > >> Subject: Re: [FFmpeg-devel] [PATCH] avfilter/vf_xcam: add xcam video > >> filter > >> > >> On 7/31/20, Zong, Wei <wei.z...@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@ffmpeg.org > >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > >> > >> To unsubscribe, visit link above, or email > >> ffmpeg-devel-requ...@ffmpeg.org > >> with subject "unsubscribe". > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > To unsubscribe, visit link above, or email > > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". -- --------------------------- *^_^* Many Thanks & Best Regards! Amy Zhao 赵娟 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
