On 04/21/2017 10:15 PM, Hendrik Leppkes wrote: > On Fri, Apr 21, 2017 at 3:34 PM, Xiaolei Yu <dreifachst...@gmail.com> wrote: >> Some android devices do not properly align the input surface of MediaCodec >> (Nexus 4, Galxy Note 2) and >> we are forced to specify a multiple of 16 as the video width. A possible >> workaround is to insert the desired crop >> into the output sps, but I am not sure if it is legal. > > H.264 always has a coded dimension which is a multiple of 16, and any > smaller granularity on actual dimensions is achieved with cropping > parameters.
I understand coding internally handles only 16x16 blocks. But I am not sure whether a decoder is required to decode full blocks first before applying the cropping. What happens if prediction requires data out side of the cropping area? Say I have a 1088x1920 h264 file and crop it to (0,0 - 1080,1920) by editing the sps, can I expect the new file is still conformant and the decoded images match those of the original file in the cropped area? > > - Hendrik > _______________________________________________ > 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
