On Fri, Oct 14, 2016 at 12:23:02AM +0200, Andreas Cadhalpun wrote: > On 14.10.2016 00:00, Hendrik Leppkes wrote: > > On Thu, Oct 13, 2016 at 10:25 PM, Andreas Cadhalpun > > <andreas.cadhal...@googlemail.com> wrote: > >> If x is 0, 'x - 1' is in the previous line, or worse outside the buffer > >> for the first line. > >> > >> If y is 0, 'x - image->comps[compno].w' is outside the buffer. > >> > > > > I'm slightly puzzled, as you say, these are for edge handling, edges > > in this case are from the image width to buffer width, and image > > height to buffer height, respectively > > So for x or y to be zero, we would need an image thats zero width, or > > zero height, so the edge starts at zero? > > > > How does that happen, and wouldn't it be much simpler to catch that > > case earlier in the chain and simply error out? A image with either > > zero width or zero height surely is not something you can encode > > either way. > > The avctx->width/avctx->height is not zero, but libopenjpeg_copy_unpacked8 > does:
> width = avctx->width / image->comps[compno].dx;
> height = avctx->height / image->comps[compno].dy;
this looks wrong to me
the code in mj2_create_image() looks better:
cmptparm[i].dx = sub_dx[i];
cmptparm[i].dy = sub_dy[i];
cmptparm[i].w = (avctx->width + sub_dx[i] - 1) / sub_dx[i];
cmptparm[i].h = (avctx->height + sub_dy[i] - 1) / sub_dy[i];
i assume here that the buffers are large enough and that the encoder
encodes the full rounded up size
if it does not then it doesnt support odd sizes with subsampling
>
> So if e.g. avctx->height is 1 and image->comps[compno].dy is 2, height
> becomes 0. I'm not sure if that's invalid.
chroma planes being 0 sized is invalid for a normal image
you can potentially get this with tiling that some tiles have no
chroma samples but i think the code doesnt do anything odd like that
of course i could also be missing somethig
[...]
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