2018-07-18 0:22 GMT+02:00, Hendrik Leppkes <h.lepp...@gmail.com>: > On Wed, Jul 18, 2018 at 12:13 AM Carl Eugen Hoyos <ceffm...@gmail.com> > wrote: >> >> 2018-07-17 23:58 GMT+02:00, Hendrik Leppkes <h.lepp...@gmail.com>: >> > On Tue, Jul 17, 2018 at 11:54 PM Carl Eugen Hoyos <ceffm...@gmail.com> >> > wrote: >> >> >> >> 2018-07-17 21:39 GMT+02:00, Vittorio Giovara >> >> <vittorio.giov...@gmail.com>: >> >> > YUV410P requires that sizes are divisible by 4. >> >> >> >> Do you mean that AV_PIX_FMT_YUV410P requires it? >> >> Where is this documented? >> > >> > Its a consequence of the subsampling factor. 4:1:0 is one-fourth the >> > horizontal resolution and half the vertical resolution, as such the >> > width has to be a multiple of 4 for that to result in a valid chroma >> > dimension. >> >> (Apart from the fact that it appears to work here and is needed to >> archive some multimedia files.) >> Why wouldn't the chroma dimension be rounded up? > > Where is it ever specified that this would be the case?
Which other options exist? > If I'm an API user, and I get an odd image size with such a > subsampling factor, what guarantees do I have that the chroma plane is > big enough to be rounded up, and I don't overread the buffer, or > process garbage information? The exact same guarantees as for any other buffer FFmpeg provides? > Its the same with 4:2:0 images, non-mod2 images using 4:2:0 are just > flat out invalid, or non-mod4 if they are interlaced even. And such files do not exist or what exactly do you claim? > Thats why cropping info exists. You can store odd-sized images like > that if you really want to by padding it, but you need to crop it > after converting it to RGB or another format without such limitations. But that only works if that's how the encoder did it, no? > This doesn't change how the format is stored, just when cropping is applied. Then I wonder what exactly this patch fixes (if nothing is changed). Carl Eugen _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
