Newest 'x264' Questions - Stack Overflow

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• H264 Encoders other than ffmpeg x264

  5 septembre 2016, par 0pcl

  The iPhone app I am working on captures images in series within certain user-defined time interval, I am looking for a way to combine these images into H264 encoded videos. I have done some research on Google, it looks like I will have to use something like ffmpeg/mencoder on iPhone? (Also found someone ported ffmpeg to iPhone, ffmpeg4iPhone)

  However, I found that x264 is under GPL license, and requires me to open source my project if I use ffmpeg. Also found some people suggested to use Ogg Theora, but I will need to port it to iPhone if I use it. (Which I am not sure how to do it now).

  Is there any workaround for this? Any ideas? Thanks.

• Can x264 be used from Java code via JNI to decrease the resolution of RTMP streams ? [on hold]

  5 septembre 2016, par Orr151

  I would like to implement a custom RTMP transcoder to HLS format in Java. As the repackaging itself seems to be relatively clear and doable in Java, then I found the modification of the video resolution a bit challenging in Java. My plan is to avoid using existing solutions like FFmpeg or at least minimize the amount of 3rd party frameworks/tools integrated with my component.

  After some research it seems that reusage of JCodec and Xuggler can be challenging as both project are idle for a while. Also I'm not sure if their performance is acceptable. That's why I would like to integrate directly with x264 library via JNI from Java code.

  Is integration with x264/libx264 from Java code to decrease resolution/bitrate doable and is it a good idea? Could you please suggest any other solutions?

  Thanks!

• FFmpeg cannot recognize a preset even though it does exsist Ubuntu 12.04

  31 août 2016, par Ahmad Tahboub

  I have installed ffmpeg and x264 folloowing the steps in this documentation :http://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide

  Now I have this line to execute :

  sudo /usr/bin/ffmpeg -i input_file.flv -f flv -vcodec libx264 -vpre normal -r 25 -s 0x0 -aspect 1.7777777777778 -padcolor 000000 -padtop 0 -padbottom 0 -padleft 0 -padright 0 -acodec libfaac -ab 128000 -ar 22050 output_file.flv
  
  Input #0, flv, from 'WIN! Jwow.flv':
    Metadata:
      starttime       : 0
      totalduration   : 101
      totaldatarate   : 865
      bytelength      : 10897460
      canseekontime   : true
      sourcedata      : BD58B2E43HH1338284027987695
      purl            : 
      pmsg            : 
    Duration: 00:01:40.66, start: 0.000000, bitrate: 877 kb/s
      Stream #0.0: Video: h264 (Main), yuv420p, 640x360, 745 kb/s, 29.97 tbr, 1k tbn, 59.94 tbc
      Stream #0.1: Audio: aac, 44100 Hz, stereo, s16, 131 kb/s
  **File for preset 'normal' not found**
  

  I have the presets in the the following directories:

  /usr/share/ffmpeg
  /usr/local/share/ffmpeg
  /home/user/.ffmpeg
  /usr/local/src/ffmpeg/presets
  

  And still getting the same error: File for preset 'normal' not found

  What is the problem here, Please Help!

  Extra info - this is what i get when i do ffmpeg -version

  ffmpeg version git-2012-05-31-60de761
  built on May 31 2012 15:54:11 with gcc 4.6.3
  configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree --enable-version3 --enable-x11grab
  

  Thanks!

• Enhance text image in x264 encoding

  24 août 2016, par useprxf

  I'm making use of x264 for remote desktop streaming. The goal is to achieve both low bitrate and high video quality within the computation budget. The current parameter set I used almost achieve this goal, but it fails in handling images with many texts (e.g. browsing websites scene). The text in image is blurred and affects the user experience.

  I think it's the quantization in x264 that causes this. The quantization after DCT transform will eliminate high frequency sinals which mainly correspond to texts in image.

  So, my question is how to improve the text quality in x264 encoding?

  My idea: when the bitrate stays at a low level for a period of time,

  1. set crf to be 0 (lossless);
  2. encode current frame as an IDR frame and then send it;
  3. recover the crf.

  Also, a flag should be used to prevent resending when bitrate keeps low for a long time. I haven't try this method since I don't know how to mark a frame as an IDR frame manully and then encode it.

• Enhance text image in x264encoding

  23 août 2016, par useprxf

  I'm making use of x264 for remote desktop streaming. The goal is to achieve both low bitrate and high video quality within the computation budget. The current parameter set I used almost achieve this goal, but it fails in handling images with many texts (e.g. browsing websites schene). The text in image is blurred and affects the user experience.

  I think it's the quantization in x264 that causes this. The quantization after DCT transform will eliminate high frequency sinals which mainly correspond to texts in image.

  So, my question is how to do improve the text quality in x264 encoding?

  My idea: when the bitrate stays at a low level for a period of time,

  1. set crf to be 0 (lossless);
  2. encode current frame as an IDR frame and then send it;
  3. recover the crf.

  Also, a flag should be used to prevent resending when bitrate keeps low for a long time. I haven't try this method since I don't know how to mark a frame as an IDR frame manully and then encode it.