Newest 'x264' Questions - Stack Overflow

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• Distorted vlc playback with x264 encoded file

  24 juillet 2012, par monzie

  I have captured raw video in rgb format from my webcam using ffmpeg:

  ffmpeg -f video4linux2 -s 320x240 -r 10 -i /dev/video0 -f rawvideo \
  -pix-fmt rgb24 -r10 webcam.rgb24
  

  This raw video file plays ok in mplayer.

  I encode this file using x264:

  x264 --input-res 320x240 --demuxer raw --input-fmt rgb24 --fps 10 \
  -o webcam.mkv webcam.rgb24
  

  However when I try to play webcam.mkv with vlc it is an interlaced, distorted image.

  I don't know what I am doing wrong.

• Is it possible to encode one yuv file to 3 h.264 files with different bitrates with one command ?

  24 juillet 2012, par Richard Knop

  I have a YUV file. I need to encode it to H.264 but using three different bitrates. Is it possible to do it with one command so the yuv file does not need to be processed muttiple times?

  Here's what I do right now:

  x264 -B 600 -o /path/to/output_first.264 /path/to/input.yuv
  x264 -B 800 -o /path/to/output_second.264 /path/to/input.yuv
  x264 -B 1000 -o /path/to/output_second.264 /path/to/input.yuv
  

  Is it possible to do it in one command to make it faster? YUV file can be quite big so I don't want to extract it three times in a row. And all three encoding processes use the same input YUV file so I guess it should be possible.

• How to encode multiple videos parallel (Debian)

  20 juillet 2012, par Wolfen

  I'd like to encode some video files either to MP4 and X264 format in Linux Debian.

  It is very important that I encode multiple files parallel. E.g. I want to encode two videos parallel on a Dual Code Machine and put the other videos in a queue. When a Video is finished I want the free core to encode the next video in the queue. Also even when this'd work with x264 I don't know about MP4.

  What is the best approach here? x264 supports parallel encoding but I don't know whether this is parallel encoding for multiple files or parallel encodings of different version for one single video. Is there a way I can assign a encoding-process to core1 and another to core2?

  Sincerly, wolfen

• Should I compile with -mssse3 in the presence of ASM SSSE3 code ?

  19 juillet 2012, par Philos

  I have a question regarding compiling a build of x264 on GCC.

  x264 has assembly code dealing with instruction sets such as SSE3 and SSSE3 and by default has auto-vectorization disabled in the makefile.

  Should I compile it with the -mssse3 flag anyways or could that actually cause a loss in performance?

  And does -mssse3 imply -msse3 or is SSE3 separate from SSSE3?

• GStreamer x264enc and SIGSEGV on Android

  18 juillet 2012, par Cipi

  I am trying to play around with GStreamer-java and it's h.264 encoder (x264enc) on Android.

  Now, I tried to encode raw video from test video source (set its is-live property to TRUE), and when data starts flowing into the x264enc Element, I get SIGSEGV in libx264.so and my app crashes. And it looks like code is dereferencing a NULL... Exact error location is in file "gstreamer_ndk_bundle/x264/encoder/analyse.c" line 963. And it is this line:

  h->mc.memcpy_aligned( h->mb.pic.i8x8_dct_buf, h->dct.luma8x8, sizeof(h->mb.pic.i8x8_dct_buf) );
  

  My device's CPU is Cortex 8 and it has NEON feature...

  I tried to printout to a file all h structure fields, and no field is uninitialized.

  Android DEBUG info from LogCat: HERE

  My questions:

  1. How can I know what is throwing SIGSEGV, because this line of code seems to be ok?
  2. Is this a known bug or an expected behavior of x264 encoder on ARM CPU or I am missing some encoder configuration?
  3. I noticed that if I set property analyse of the encoder to 0x3:0x113 (some random value I found online) I don't get SIGSEGV, encoder seems to work, but I get error in pipeline: Data flow error. Can I just set analyse to a meaningful value?

  Update

  I fprintf-ed all important "h" fields just before execution runs in x264_mb_analyse_intra() function and just before the line that it breaks, guess it could help: http://pastebin.com/sAfX239j