On 9/6/2018 7:26 PM, Michael Niedermayer wrote: > On Thu, Sep 06, 2018 at 01:10:31PM -0300, James Almer wrote: >> On 9/4/2018 5:09 PM, Michael Niedermayer wrote: >>> On Mon, Sep 03, 2018 at 10:29:13AM -0300, James Almer wrote: >>>> On 9/3/2018 5:17 AM, Michael Niedermayer wrote: >>>>> On Sun, Sep 02, 2018 at 09:34:23PM -0300, James Almer wrote: >>>>>> From: Luca Barbato <lu_z...@gentoo.org> >>>>>> >>>>>> Merged-by: James Almer <jamr...@gmail.com> >>>>>> --- >>>>>> This is the next merge in the queue. It's a critical part of the AVFrame >>>>>> API, >>>>>> so even if FATE passes I'd rather have others look at it and test in case >>>>>> something breaks. >>>>>> >>>>>> The only difference compared to the libav commit is the "32 - 1" padding >>>>>> per >>>>>> plane when allocating the buffer, which was only in our tree. >>>>> >>>>> why is the STRIDE_ALIGN (which is a thing in units of bytes along the >>>>> horizontal axis) added to padded_height which is vertical axis ? >>>>> This is not done prior to the change >>>> >>>> The only way to keep this padding we currently have in the tree applied >>>> to the buffer allocation for each plane like it was before the change >>>> (Except it'll now be one continuous buffer instead of one per plane) is >>>> by passing it alongside the height parameter to >>>> av_image_fill_pointers(). The result is essentially the same. >>>> >>>> Do you want me to change the name of the variable, or remove it and pass >>>> 32 - 1 to both av_image_fill_pointers() calls directly? Removing the >>>> padding will probably just make whatever overreads prompted its addition >>>> to resurface. >>>> Alternatively, i can just no-op this merge and move on. >>> >>> allocating one plane instead of 3 is better obviously so i dont think this >>> should be no-oped unless someone implements this differently >>> >>> i dont think the padding can be removed saftely but i might be missing >>> something >>> also i do not remember this 100% >>> >>> what i see and i may have misunderstood your reply but the code before >>> places >>> a few bytes between planes, the new code places a few lines, that is alot >>> more >>> space. Its not even the best that can be done with the current API. For >>> example >>> the number of extra lines would generally be 1 to provide sufficient padding >>> at most reaslistic resolutions. >>> >>> also there is the independant question on the API, do we want/need to make >>> adding padding between planes easier?> >>> actually i think that if we change from 31 bytes to X lines padding then >>> this >>> should be a commit seperate of the 3->1 change. This would make bisect much >>> more meaningfull and its rather trivial to split this. >> >> Do you have a suggestion on how to choose how many lines of padding to >> add? > > something like (with rounding up) > bytes * horizontal_chroma_subsampling / width * vertical_chroma_subsampling
Isn't a calculation like this already being done? > > >> And how would it be done? Just passing (h + padding_lines) to >> av_buffer_alloc() pre merge, and to av_image_fill_pointers() post merge? > > possible > > >> >> It would also be faster if you could commit that change instead. > > thinking of this, its maybe simpler to adjust data[*] by these to get > exactly teh same effect as before Is this before or after the merge? Because after the merge it's av_image_fill_pointers() who does all the work, and get_video_buffer() has no control over the pointers. Nothing about this is obvious to me, so i ask again if you could implement this instead. Otherwise I'll just no-op the merge and add it to the list of skipped changes in case someone else wants to give it a try at some other time. > > > thx > > [...] > > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
