On Tue, Dec 15, 2020 at 4:44 AM Mark Thompson <s...@jkqxz.net> wrote:
> On 14/12/2020 13:31, Nuo Mi wrote: > > Hi Mark, > > I have almost done the cbs for sps, pps, and slice header. I will start > to > > implement the parser. > > This looks fun :) > > > Few questions for you: > > 1. We need over-read some nals to detect the frame boundaries. But those > > nals may switch/replace sps/pps. Do we need to use an output cbs and get > > frames from the output cbs? > > I'm not seeing where this can happen - if you see a new parameter set then > you must be in a new AU so you don't parse it, while a new VCL NAL as part > of a new frame with no PS before it must have a parsable header? (Or am I > missing some problematic case?) > > > 2. We can't handle an incompleted nal in current cbs. > > > https://github.com/FFmpeg/FFmpeg/blob/03c8fe49ea3f2a2444607e541dff15a1ccd7f0c2/libavcodec/h2645_parse.c#L437 > , > > do we have a plan to fix it? What's your suggstion for the frame split? > > I'm unsure what the question is. You will always need to keep reading > until you split a valid NAL unit which isn't in the current AU (noting that > a slice is the last slice in the current frame is never sufficient, because > suffixes might follow). > > I want to feed the input buffer to cbs and get nal units from it. Seems it does not work like this. We still need a frame split in the parser. And feed the entire frame to cbs. > > 3. How to well test the cbs? > > Passthrough is the best initial test, by making an h266_metadata bsf (even > if it has no options). The existing test coverage in FATE of CBS is > primarily driven by this - for H.26[45], the input streams there are a > subset of the H.26[45].1 conformance test streams chosen to cover as much > of the header space as possible. > > I recommend enabling the write support ASAP (by adding the second include > of cbs_h266_syntax_template.c), because the double build can shake out > other problems too. > > My original plan is cbs->parser->vvdec decoder->60% comfornace passrate -> check in -> h266_metadata. are you suggest we implement h266_metadata firstly? thanks Thanks, > > - Mark > _______________________________________________ > 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".
