* modules/codec/x264.c: backport [25152] fix for x264 threads=0 (auto)

NEWS

@@ -5,7 +5,7 @@ Changes between 0.8.6d and 0.8.6e (not yet released):
 
 Various bugfixes:
  * Resume playback for viewing content over FTP
- * Fix XShm detection with remote X11
+ * Fixed XShm detection with remote X11
 
 Security updates:
  * Subtitle demuxers overflow (CVE-2007-6681)
@@ -24,13 +24,16 @@ Audio output:
  * Fixed 5.1 audio on ALSA
 
 Access:
- * Fix some RTSP hanging and user/password passing through RTSP URLs
+ * Fixed some RTSP hanging and user/password passing through RTSP URLs
 
 Stream output:
  * Fixed waiting for SPS/PPS problem in H.264 packetizer
 
 Encoders:
  * Improved compatibility for creating H.264 video playable on iPhones
+ * Fixed detection of optimal amount of threads for multi-threaded H.264
+   encoding on multi-cpu systems
+   - Note that this is used when transcode threads is set to 0 (default)
 
 Mac OS X Interface & Port:
  * Restored compatibility with Mac OS X 10.3.9

modules/codec/x264.c

@@ -1057,11 +1057,12 @@ static int  Open ( vlc_object_t *p_this )
         p_sys->param.cpu &= ~X264_CPU_SSE2;
     }
 
+    /* BUILD 29 adds support for multi-threaded encoding while BUILD 49 (r543)
+       also adds support for threads = 0 for automatically selecting an optimal
+       value (cores * 1.5) based on detected CPUs. Default behavior for x264 is
+       threads = 1, however VLC usage differs and uses threads = 0 (auto) by
+       default unless ofcourse transcode threads is explicitly specified.. */
 #if X264_BUILD >= 29
-    /* As of r543 x264 will autodetect the number of cpus and will set
-       the number of threads accordingly unless ofcourse the number of
-       threads is explicitly specified... */
-    if( p_enc->i_threads >= 1 )
     p_sys->param.i_threads = p_enc->i_threads;
 #endif