[vlc-devel] commit: contrib: turn off Thumb ISA for libavcodec and libmad ( Rémi Denis-Courmont )

[Måns Rullgård]

"Rémi Denis-Courmont" <remi at remlab.net> writes:

> Le mardi 1 septembre 2009 23:40:23 Måns Rullgård, vous avez écrit :
>> > I just started decoding MPEG4 Part 2 (in MKV with AAC) or Part 10
>> > (in AVI with MP3). Disabling video decoding worked around it. VLC
>> > did not use FFMPEG for MKV, AVI, AAC nor MP3. It fails immediately,
>> > as far as I can tell.
>>
>> Compiler flags as below?
>
> Yes. I just retried with the entire stack (VLC+contribs)
> -mtune=cortex-a8 -mcpu=cortex-a8 -march=arvm7-a -mfpu=neon
> -O3 -fno-tree-vectorize
>
> and I get the exact same result.
>
>> Can you get a core dump?
>> Where does it crash?
>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x4159d490 (LWP 2571)]
> 0x4285bfcc in ff_simple_idct_put_neon ()
>    from /opt/VideoLAN/lib/vlc/codec/libavcodec_plugin.so
> 0x4285bfcc <ff_simple_idct_put_neon+24>:        vld1.64 {d0-d1}, [r3, :128]
> (gdb) bt
> #0  0x4285bfcc in ff_simple_idct_put_neon ()
>    from /opt/VideoLAN/lib/vlc/codec/libavcodec_plugin.so
> #1  0x00000000 in ?? ()

Please run these gdb command there:

(gdb) info registers
(gdb) disas $pc-24 $pc+24

> (I guess VLC contribs strips ffmpeg debug symbols).
>
>> Can you decode the file with a standalone FFmpeg build?
>
> Yes.

That suggests the problem is not in FFmpeg.

-- 
Måns Rullgård
mans at mansr.com