[FFmpeg-devel] [RFC] Windows issues with av_destruct_packet_nofree

Måns Rullgård mans
Wed Feb 18 18:45:15 CET 2009

Reimar D?ffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> writes:

> On Wed, Feb 18, 2009 at 05:32:33PM +0000, M?ns Rullg?rd wrote:
>> Art Clarke <aclarke at xuggle.com> writes:
>> > I just spent somewhere between 2-3 weeks tracking down a weird bug that
>> > resulted in our code creating corrupted files on Windows but working fine on
>> > Linux and Mac.  The issue, it turns out, affects people who allocate their
>> > own AVPackets, and then try to use av_interleaved_write_frame on Windows.
>> > That's because on Windows, "av_destruct_packet_nofree" outside of the libav
>> > DLL's themselves is NOT the same as "av_destruct_packet_nofree" inside the
>> > libav DLLs.  As a result when using av_interleaved_write_frame on Windows,
>> > packet you might think FFMPEG is copying, aren't actually duplicated and
>> > memory corruption results.
>> For the record, such behaviour with respect to comparing function
>> addresses is in violation of the C standard.
> Nevertheless workarounds were already discussed, I thought we mostly
> agreed the current code is ugly - I forgot what happened then though...

Yes, I remember the discussions.  The symptom that time was memory
leaks when using bitstream filters with shared libs.

M?ns Rullg?rd
mans at mansr.com

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