[libav-bugs] [Bug 351] New: uninitialized values in avformat_find_stream_info when reading flv

bugzilla-daemon at aruru.libav.org bugzilla-daemon at aruru.libav.org
Fri Aug 17 09:29:22 CEST 2012


           Summary: uninitialized values in avformat_find_stream_info when
                    reading flv
           Product: Libav
           Version: 0.8
          Platform: IA64
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: Normal
         Component: libavformat
        AssignedTo: bugzilla at libav.org
        ReportedBy: libav at henning-thielemann.de

Created attachment 343
  --> http://bugzilla.libav.org/attachment.cgi?id=343
beginning of a flashsv file that corrups find_stream_info

I have recorded a screencast using avconv and flash screen video codec
(flashsv). See attached beginning of the file.
When I ask avconv for info of the file then valgrind reports a problem with
uninitialized values.

$ head -c 1000 <screencast.flv >corrupt-stream-info.flv
$ valgrind avconv -i corrupt-screen-info.flv 
==3391== Memcheck, a memory error detector
==3391== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==3391== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==3391== Command: avconv -i corrupt-screen-info.flv
avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the
Libav developers
  built on Jun 12 2012 16:52:09 with gcc 4.6.3
==3391== Conditional jump or move depends on uninitialised value(s)
==3391==    at 0x865B4E0: inflateReset2 (in
==3391==    by 0x865B5D8: inflateInit2_ (in
==3391==    by 0x55AFAB0: ??? (in
==3391==    by 0x59A3E6D: avcodec_open2 (in
==3391==    by 0x531F424: ??? (in
==3391==    by 0x532452D: avformat_find_stream_info (in
==3391==    by 0x40DCBE: ??? (in /usr/bin/avconv)
==3391==    by 0x413356: ??? (in /usr/bin/avconv)
==3391==    by 0x4134E4: ??? (in /usr/bin/avconv)
==3391==    by 0x404DD6: ??? (in /usr/bin/avconv)
==3391==    by 0x6F4276C: (below main) (libc-start.c:226)
[flv @ 0xb229820] decoding for stream 1 failed
[flv @ 0xb229820] Estimating duration from bitrate, this may be inaccurate
Input #0, flv, from 'corrupt-screen-info.flv':
    encoder         : Lavf53.21.0
  Duration: 00:00:00.00, start: 0.000000, bitrate: 400 kb/s
    Stream #0.0: Video: flashsv, bgr24, 1366x768, 200 kb/s, 1k tbr, 1k tbn, 1k
    Stream #0.1: Audio: [0][0][0][0] / 0x0000, 0 channels, 200 kb/s
At least one output file must be specified
==3391== HEAP SUMMARY:
==3391==     in use at exit: 0 bytes in 0 blocks
==3391==   total heap usage: 51 allocs, 51 frees, 3,877,188 bytes allocated
==3391== All heap blocks were freed -- no leaks are possible
==3391== For counts of detected and suppressed errors, rerun with: -v
==3391== Use --track-origins=yes to see where uninitialised values come from
==3391== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2)

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