[FFmpeg-devel] [PATCH 2/2] avformat/mpegts: Skip over broken 0x80 headers

[Christophe Gisquet]

Hi,

2016-04-27 23:58 GMT+02:00 Carl Eugen Hoyos <cehoyos at ag.or.at>:
> Mark Thompson <sw <at> jkqxz.net> writes:
>
>> Unless someone can show what created this file and that
>> it might make more, I suggest that the hack workaround
>> should be removed.
>
> Is there a valid file affected by the applied patch?
> It is very important that FFmpeg also decodes invalid
> files as long as no valid files are affected.

The file is invalid in the sense that someone didn't remove an
encapsulation (*) from another protocol layer (ie did a very bad job),
not because of a somewhat known implementation bug due to misreading
some specs (like we have for avi, mpeg-4 part 2, and already hevc,
etc).

I wonder, for instance, if I stream copy that sequence into another
container, would the issue remain, and thus require the bugfix to be
copied yet somewhere else?

You even think so:
> This is of course assuming that the file was not created
> for the sole purpose to produce such changes in FFmpeg.

i.e., is there a software/application that needs this, or is it just
someone that expected dumping the stream to work while
debugging/implementing something entirely different?

In the end, if that was not that rare, I wonder if that wouldn't be
the job of a bitstream filter.

(*) although we probably support some strange things iirc, like
DTS-IN-WAV-IN-AVI.

-- 
Christophe