On Mon, Jun 13, 2022 at 12:10:44PM +0200, Paul B Mahol wrote: > On Mon, Jun 13, 2022 at 11:48 AM Anton Khirnov <[email protected]> wrote: > > > Quoting Paul B Mahol (2022-06-13 11:34:44) > > > On Mon, Jun 13, 2022 at 11:10 AM Anton Khirnov <[email protected]> > > wrote: > > > > > > > Quoting Paul B Mahol (2022-06-13 10:04:04) > > > > > On Sat, Jun 11, 2022 at 4:55 PM Michael Niedermayer < > > > > [email protected]> > > > > > wrote: > > > > > > > > > > > On Sat, Jun 11, 2022 at 10:47:57AM +0200, Paul B Mahol wrote: > > > > > > > Have you actually tested this "change" ? > > > > > > > > > > > > On every file i found > > > > > > 6-methyl-5-hepten-2-one-CC-db_small.avi > > > > > > fmvcVirtualDub_small.avi > > > > > > skrzyzowanie4.avi > > > > > > fmvc-poc.avi > > > > > > > > > > > > are there any other files i should test it on ? > > > > > > > > > > > > > > > > Yes, the ones where stride != width. > > > > > > > > Give examples of such files then. And add more tests. > > > > > > > > You really should try to be more helpful if you care about this code > > > > working. > > > > > > > > > Code works perfectly from start. There are always attempts to break it. > > > Your attempts to belittle my work are futile. > > > > Perfect code should live in an external repository that is locked > > against modification. > > > > The ffmpeg repository is only for imperfect code that evolves with time, > > and so requires changes. > > > > > I dunno what Michael attempts to fix. Decoder works fine with valid files. > I doubt that encoder would encode random bytes or padding into valid file > bitstream.
the stride*4 / width*4 change was because of 2 things.
first with AV_PIX_FMT_BGR24 the data stored is not width*4
stride is in units of 4 bytes for some reason, so stride*4
fixes this
The 2nd issue is that the code addresses it by "s->stride * 4"
so the buffer allocation should be stride*4 if we belive the
other code is correct
src = s->buffer;
...
for (y = 0; y < avctx->height; y++) {
...
src += s->stride * 4;
width*4 works because its bigger than stride*4 for BGR24 which is what all
samples i have use.
also
ssrc = s->buffer;
...
for (y = 0; y < avctx->height; y++) {
...
ssrc += s->stride * 4;
and
dst = (uint32_t *)s->buffer;
for (block = 0, y = 0; y < s->yb; y++) {
int block_h = s->blocks[block].h;
uint32_t *rect = dst;
for (x = 0; x < s->xb; x++) {
int block_w = s->blocks[block].w;
uint32_t *row = dst;
block_h = s->blocks[block].h;
if (s->blocks[block].xor) {
for (k = 0; k < block_h; k++) {
uint32_t *column = dst;
for (l = 0; l < block_w; l++)
*dst++ ^= *src++;
dst = &column[s->stride];
}
}
dst = &row[block_w];
++block;
}
dst = &rect[block_h * s->stride];
}
Again, if you have fmvc files with more odd widths or other pixel formats
these would be very welcome. I can just say the code as is in git is wrong
and the buffer size as is in git is wrong. I noticed this when i added
a check to see if the buffer is only partly filled and realized its
always partly filled even when the whole image is actually touched
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Rewriting code that is poorly written but fully understood is good.
Rewriting code that one doesnt understand is a sign that one is less smart
than the original author, trying to rewrite it will not make it better.
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