On Sun, Sep 04, 2011 at 04:13:52PM -0400, Lennart Sorensen wrote: > Are there any that don't experience it? > > I just tried running ffmpeg on a power6+ machine under gdb and got: > > Program received signal SIGSEGV, Segmentation fault. > 0x0f6ff37c in ff_fft_calc_altivec () at > /root/libav-0.7.1/libavcodec/ppc/fft_altivec_s.S:447 > 447 DECL_FFTS 0 > (gdb) where > #0 0x0f6ff37c in ff_fft_calc_altivec () at > /root/libav-0.7.1/libavcodec/ppc/fft_altivec_s.S:447 > #1 0x0f6feaa8 in ff_imdct_half_altivec (s=<optimized out>, output=<optimized > out>, input=<optimized out>) at > /root/libav-0.7.1/libavcodec/ppc/fft_altivec.c:93 > #2 0x0f437ce8 in imdct_and_windowing (ac=0x10040ca0, sce=0xf7f260c0) at > /root/libav-0.7.1/libavcodec/aacdec.c:1856 > #3 0x0f43caa8 in spectral_to_sample (ac=<optimized out>) at > /root/libav-0.7.1/libavcodec/aacdec.c:2015 > #4 aac_decode_frame_int (avctx=<optimized out>, data=0xf7f95020, > data_size=0xffffda78, gb=<optimized out>) at > /root/libav-0.7.1/libavcodec/aacdec.c:2170 > #5 0x0f43ccec in aac_decode_frame (avctx=<optimized out>, data=<optimized > out>, data_size=<optimized out>, avpkt=<optimized out>) > at /root/libav-0.7.1/libavcodec/aacdec.c:2216 > #6 0x0f77f25c in avcodec_decode_audio3 (avctx=0x100406a0, samples=<optimized > out>, frame_size_ptr=<optimized out>, avpkt=<optimized out>) > at /root/libav-0.7.1/libavcodec/utils.c:726 > #7 0x0ff3f924 in try_decode_frame (avpkt=0x100466e0, st=0x1003ede0) at > /root/libav-0.7.1/libavformat/utils.c:2104 > #8 av_find_stream_info (ic=0x1003e840) at > /root/libav-0.7.1/libavformat/utils.c:2388 > #9 0x1000b200 in opt_input_file (opt=<optimized out>, filename=<optimized > out>) at /root/libav-0.7.1/ffmpeg.c:3271 > #10 0x1000f0fc in parse_options (argc=4, argv=0xffffe184, options=0x10026720, > parse_arg_function=0x1000cfd0 <opt_output_file>) at > /root/libav-0.7.1/cmdutils.c:287 > #11 0x100067c8 in main (argc=4, argv=<optimized out>) at > /root/libav-0.7.1/ffmpeg.c:4444 > (gdb) Program received signal SIGSEGV, Segmentation fault. > > Anyone have an idea what to look at exactly? I really wish debug builds > wouldn't have so much 'optimized out' stuff that makes reading stack > traces so hard.
So it turns out it was reported to ffmpeg upstream 3 months ago and fixed already. http://ffmpeg.org/trac/ffmpeg/ticket/272 The patch to libavcodec/ppc/asm.S is in comment #8. It no longer segfaults for me with that patch applied. Apparently when compiling in pic mode, the new assembly altived fft code always segfaults, while the old version was C code and worked fine. Apparently an offset calculation was done wrong as far as I understand it. -- Len Sorensen -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
