[Libav-user] FFmpeg + OpenAL - playback streaming sound from video won't work
Carl Eugen Hoyos
cehoyos at ag.or.at
Tue Jan 28 13:22:03 CET 2014
Jan Drabner <jan at ...> writes:
> But I never asked for support. I reported what is in my
> opinion bug.
> swr_convert crashes under some circumstances,
> without telling any reason.
Yes and no.
If you had provided a backtrace as requested on
http://ffmpeg.org/bugreports.html I suspect one would
have been able to see what's wrong.
(Everybody was able to guess what's wrong but it is
often a bad idea to rely on guessing when answering
The relevant functions take a pointer to input data
structures and a pointer to output data structures
as parameters. In your case, you initialised the
conversion functions saying "I want to convert to
a planar format", so the actual conversion function
expected you to pass a pointer to pointers. But
instead you passed a pointer to allocated memory
(it may have been different but this is what
generally happens). Do you really think there is a
possibility for the conversion function to know
(in advance) that dereferencing the pointer you
passed will lead to a segfault? And do you agree
that it is impossible to "tell a reason" in this
> If that is not a bug, or a severely lacking feature or
> documentation, I don't know what is.
It may be missing documentation (it possibly is) but
then you should not write "crash" but instead send
a documentation update (now) to ffmpeg-devel.
> I still have no idea why it should not be possible
> to convert from any format to any other.
That is exactly what it does.
> sws_scale can do that just fine.
But it will of course also (immediately) crash
if you pass a pointer to RGB24 after initialising
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