2012/1/16 Maksym Veremeyenko <ve...@m1stereo.tv>:
> Hi,
>
> i was testing a recording from decklink into the avformat consumer with
> simple code:
>
> #include <stdio.h>
> #include <unistd.h>
> #include <framework/mlt.h>
>
> int main( int argc, char *argv[] )
> {
> mlt_consumer consumer;
> mlt_producer producer;
> mlt_profile profile;
> mlt_repository repo;
>
> repo = mlt_factory_init(NULL);
>
> mlt_log_set_level(MLT_LOG_DEBUG);
>
> // Initialise the factory
> if(repo) {
> profile = mlt_profile_init("dv_pal");
> producer = mlt_factory_producer(profile, "decklink", "0");
> if(!producer)
> fprintf(stderr, "ERROR: Failed to create producer\n");
> else {
> consumer = mlt_factory_consumer(profile, "avformat",
> "mlt_rec_01.mov");
> if(!consumer)
> fprintf(stderr, "ERROR: Failed to create consumer\n");
> else {
> mlt_properties consumer_properties =
> mlt_consumer_properties(consumer);
> mlt_properties_set(consumer_properties, "properties", "DV");
> mlt_consumer_connect(consumer,
> mlt_producer_service(producer));
> mlt_consumer_start(consumer);
> fprintf(stderr, "press any key to stop");
> // getchar();
> mlt_consumer_stop(consumer);
I do not think there is much attention to avoidance of a race
condition in the asynchronous start function followed immediately by a
stop function in most consumers.
> fprintf(stderr, "\nstopped\n");
> mlt_consumer_close(consumer);
> };
> mlt_producer_close(producer);
> };
> mlt_factory_close();
> }
> else
> fprintf(stderr, "ERROR: Unable to locate factory modules\n" );
>
> return 0;
> };
>
>
> but that cause a SIGSEGV:
>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7fffeb243700 (LWP 568)]
> flush_cluster_buffer (s=0x7fffe400b2e0) at libavformat/movenc.c:2210
> 2210 for (i=0; i<mov->nb_streams; i++){
> Missing separate debuginfos, use: debuginfo-install
> SDL-1.2.14-11.fc14.x86_64 alsa-lib-1.0.24-1.fc14.x86_64
> cairo-1.10.2-1.fc14.x86_64 expat-2.0.1-10.fc13.x86_64
> fontconfig-2.8.0-2.fc14.x86_64 freetype-2.4.2-5.fc14.x86_64
> gdk-pixbuf2-2.22.0-2.fc14.x86_64 glib2-2.26.0-2.fc14.x86_64
> glibc-2.13-2.x86_64 gsm-1.0.13-2.fc12.x86_64 gtk2-2.22.0-2.fc14.x86_64
> libX11-1.3.4-4.fc14.x86_64 libXau-1.0.6-1.fc14.x86_64
> libXcomposite-0.4.2-1.fc14.x86_64 libXcursor-1.1.10-5.fc14.x86_64
> libXdamage-1.1.3-1.fc14.x86_64 libXext-1.1.2-2.fc14.x86_64
> libXfixes-4.0.5-1.fc14.x86_64 libXi-1.3.2-1.fc14.x86_64
> libXinerama-1.1-2.fc13.x86_64 libXrandr-1.3.0-5.fc13.x86_64
> libXrender-0.9.6-1.fc14.x86_64 libdv-1.0.0-9.fc13.x86_64
> libgcc-4.5.1-4.fc14.x86_64 libgomp-4.5.1-4.fc14.x86_64
> libogg-1.2.0-1.fc14.x86_64 libpng-1.2.46-1.fc14.x86_64
> libselinux-2.0.96-6.fc14.1.x86_64 libstdc++-4.5.1-4.fc14.x86_64
> libtheora-1.1.1-1.fc13.x86_64 libtool-ltdl-2.2.10-3.fc14.x86_64
> libvorbis-1.3.1-2.fc14.x86_64 libxcb-1.7-1.fc14.x86_64
> libxml2-2.7.7-3.fc14.x86_64 pango-1.28.1-5.fc14.x86_64
> pixman-0.18.4-1.fc14.x86_64 sox-14.3.2-1.fc14.x86_64
> speex-1.2-0.12.rc1.fc12.x86_64 zlib-1.2.5-2.fc14.x86_64
> (gdb) bt
> #0 flush_cluster_buffer (s=0x7fffe400b2e0) at libavformat/movenc.c:2210
> #1 0x00007fffef2edb37 in mov_write_trailer (s=<value optimized out>) at
> libavformat/movenc.c:2645
> #2 0x00007fffef34af06 in av_write_trailer (s=0x7fffe400b2e0) at
> libavformat/utils.c:3562
> #3 0x00007fffef5ab9a2 in consumer_thread (arg=0x693bf0) at
> consumer_avformat.c:1872
> #4 0x0000003a71006ccb in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003a70ce0c2d in clone () from /lib64/libc.so.6
>
> wrong test code where mlt_consumer_stop was called immediately after
> mlt_consumer_start caused that sideeffect.
>
> to resolve such condition i attached a patch that properly determinate
> consumer's thread finish and avoid writing /trailer/ if no /header was
> written..
Before I apply this, I want to analyze whether there is something I
can do in the framework mlt_consumer.c to make it easier for all
consumers to avoid race condition.
--
+-DRD-+
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