[FFmpeg-devel] [PATCH] Fix for memory leak in mov format

[Art Clarke]

Hi folks,

This is my first patch submitted, so please let me know if you need
additional information or if I screwed up the format in some way.

Description of problem:
The mov demuxer allocates some private data on each AVStream it adds, but
never frees the data.

How to reproduce:
Use av_open_input_file() to open a .mov file, then call
av_close_input_file().  Run program through a memory checking tool (e.g.
valgrind).

Description of fix:
When closing a .mov format file, free the allocated MOVContext object and
null the AVFormatContext->priv_data value.

Pre-Patch Results (SVN r13158)
"make test" tests pass (assuming "configure" has no options passed in).

Valgrind results (test opens .mov file, decodes all audio and video, remixes
audio in special ways, and then encodes a new FLV file):
valgrind --leak-check=full ../aaffmpeg_test
com::vlideshow::aaffmpeg::AudioSamplesMixerTest 8
==21759== Memcheck, a memory error detector.
==21759== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==21759== Using LibVEX rev 1804, a library for dynamic binary translation.
==21759== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==21759== Using valgrind-3.3.0, a dynamic binary instrumentation framework.
==21759== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==21759== For more details, rerun with: -v
==21759==
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x411e540]negative ctts, ignoring

com::vlideshow::aaffmpeg::AudioSamplesMixerTest: .

tests summary: ok:1
==21759==
==21759== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 34 from 1)
==21759== malloc/free: in use at exit: 360 bytes in 3 blocks.
==21759== malloc/free: 29,788 allocs, 29,785 frees, 12,794,101 bytes
allocated.
==21759== For counts of detected errors, rerun with: -v
==21759== searching for pointers to 3 not-freed blocks.
==21759== checked 1,441,900 bytes.
==21759==
==21759== 360 bytes in 3 blocks are definitely lost in loss record 1 of 1
==21759==    at 0x4004802: memalign (vg_replace_malloc.c:460)
==21759==    by 0x462FDCA: av_malloc (mem.c:61)
==21759==    by 0x462FE59: av_mallocz (mem.c:134)
==21759==    by 0x40E7E0F: mov_read_trak (mov.c:1253)
==21759==    by 0x40E4FC5: mov_read_default (mov.c:215)
==21759==    by 0x40E5A82: mov_read_moov (mov.c:455)
==21759==    by 0x40E4FC5: mov_read_default (mov.c:215)
==21759==    by 0x40E922C: mov_read_header (mov.c:1736)
==21759==    by 0x40A4F0B: av_open_input_stream (utils.c:395)
==21759==    by 0x40A51D7: av_open_input_file (utils.c:481)
==21759==    by 0x4059B7B:
com::vlideshow::aaffmpeg::Container::openInputURL(char const*,
com::vlideshow::aaffmpeg::IContainerFormat*) (Container.cpp:91)
==21759==    by 0x4059F4D: com::vlideshow::aaffmpeg::Container::open(char
const*, com::vlideshow::aaffmpeg::IContainer::Type,
com::vlideshow::aaffmpeg::IContainerFormat*) (Container.cpp:66)
==21759==
==21759== LEAK SUMMARY:
==21759==    definitely lost: 360 bytes in 3 blocks.
==21759==      possibly lost: 0 bytes in 0 blocks.
==21759==    still reachable: 0 bytes in 0 blocks.
==21759==         suppressed: 0 bytes in 0 blocks.

Post-Patch results:
"make test" tests pass (assuming "configure has no options passed in).

Valgrind results (test opens .mov file, decodes all audio and video, remixes
audio in special ways, and then encodes a new FLV file)
valgrind --leak-check=full ../aaffmpeg_test
com::vlideshow::aaffmpeg::AudioSamplesMixerTest 8
==21917== Memcheck, a memory error detector.
==21917== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==21917== Using LibVEX rev 1804, a library for dynamic binary translation.
==21917== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==21917== Using valgrind-3.3.0, a dynamic binary instrumentation framework.
==21917== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==21917== For more details, rerun with: -v
==21917==
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x411e540]negative ctts, ignoring

com::vlideshow::aaffmpeg::AudioSamplesMixerTest: .

tests summary: ok:1
==21917==
==21917== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 34 from 1)
==21917== malloc/free: in use at exit: 0 bytes in 0 blocks.
==21917== malloc/free: 29,788 allocs, 29,788 frees, 12,794,101 bytes
allocated.
==21917== For counts of detected errors, rerun with: -v
==21917== All heap blocks were freed -- no leaks are possible.

Unified diff of patch:
svn diff -x --unified
Index: libavformat/mov.c
===================================================================
--- libavformat/mov.c   (revision 13158)
+++ libavformat/mov.c   (working copy)
@@ -1894,6 +1894,7 @@
         av_freep(&sc->drefs);
         if (sc->pb && sc->pb != s->pb)
             url_fclose(sc->pb);
+        av_freep(&sc);
     }
     if(mov->dv_demux){
         for(i=0; i<mov->dv_fctx->nb_streams; i++){
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