[FFmpeg-devel] [PATCH 4/4] tools/target_dec_fuzzer: Adjust max_pixels for IDCIN

[Paul B Mahol]

On Thu, Aug 22, 2019 at 11:24 AM Tomas Härdin <tjoppen at acc.umu.se> wrote:

> tor 2019-08-22 klockan 10:34 +0200 skrev Michael Niedermayer:
> > On Thu, Aug 22, 2019 at 10:23:40AM +0200, Paul B Mahol wrote:
> > > On Thu, Aug 22, 2019 at 10:16 AM Michael Niedermayer <
> > > michael at niedermayer.cc>
> > > wrote:
> > >
> > > > On Thu, Aug 22, 2019 at 10:09:30AM +0200, Paul B Mahol wrote:
> > > > > Why not fix issues listed in decoder code instead of this hack?
>
> I think there's better things we could have Michael do. That said:
>

Yes, more timeouts fixes as always.


>
> > > Also all this old game codecs never used very high resolutions.
> > > Max something vga, but not even that.
> >
> > limiting to 640x480 instead of 4096x4096 would give a factor of about
> > 55
> > speedup, thats still a long way from 2000 so that solves also only
> > part of it
> >
> > anyway ill provide a patch that limits resolution so theres something
> > that can be discussed.
>
> The probing in lavf/idcin.c already limits the resolution to 1024x1024.
> The only sample we have is 320x240. The Quake 2 decoder (cl_cin.c)
> limits CIN frames to 128 KiB compressed, from which the 1024x1024 limit
> in idcinvideo.c likely derives (128 KiB == 1 Mib == 1 Mipx if always
> using the shortest Huffman code). Zero-byte packets are also not
> allowed.
>
> If we're looking over this anyway we could toss in all these
> limitations, and maybe limit audio to 11025, 22050 and 44100 Hz.
>
> I also notice that idcinvideo.c contains code copy-pasted from cl_cin.c
> in Quake 2 (SmallestNode1 -> huff_smallest_node). The copyright header
> should reflect this.
>

That is sole reason why that awful code should not be kept, and instead
should be rewritten.


> /Tomas
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".