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• Increase the bitrate tolerance of ffmpeg for creating screenshots of a movie

  21 septembre 2012, par rekire

  I'm getting the error bitrate tolerance too small for bitrate so far no problem. I know that there are several switches to increase that but nothing works.

  ffmpeg -y -r 1/30 -b:v 999999k -bt 999999k -maxrate 999999k -i in.flv out%03d.jpg

  The source of that commandline is directly from ffmpeg. But that crashes :

  ffmpeg version N-44123-g5d55830 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Sep  2 2012 20:23:29 with gcc 4.7.1 (GCC)
  
    [...]
  
  Input #0, flv, from 'in.flv':
  
    Duration: 00:05:00.13, start: 0.000000, bitrate: 259 kb/s
  
      Stream #0:0: Video: flv1, yuv420p, 320x240, 1k tbr, 1k tbn, 1k tbc
  
      Stream #0:1: Audio: nellymoser, 22050 Hz, mono, s16
  
  [mjpeg @ 04356860] bitrate tolerance too small for bitrate
  
  [mjpeg @ 04317540] ff_frame_thread_encoder_init failed
  
  Output #0, image2, to 'out%03d.jpg':
  
      Stream #0:0: Video: mjpeg, yuvj420p, 320x240, q=2-31, 200 kb/s, 90k tbn, 0.03 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (flv -> mjpeg)
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  Some ideas what I'm doing wrong ?

• What are the differences between FFmpeg and Libav ? [closed]

  16 septembre 2012, par Ken

  According to the first comment for this question, and i quote

  "Libraries with this name are provided from both the FFmpeg project
  and the Libav project, but they are mutually incompatible". So I think
  the answer depends on which libavcodec do you want to use.

  by user aland and wikipedia

  What are the differences that exist between this 2 projects ?

  I'm interested in video and audio encoding to H/X264, Mp3 and AAC with Mp4/Mkv containers ; but more importantly i would like to start with a reliable and up to date library with a permissive license and widely supported on as many platforms as possible.

• Why I became a HTML5 co-editor

  15 août 2012, par silvia

  A few weeks ago, I had the honor to be appointed as part of the editorial team of the W3C HTML5 specification.

  Since Ian Hickson had recently decided to focus solely on editing the WHATWG HTML living standard specification, the W3C started looking for other editors to take the existing HTML5 specification to REC level. REC level is what other standards organizations call a “ratified standard”.

  But what does REC level really mean for HTML ?

  In my probably somewhat subjective view, recommendation level means that a snapshot is taken of the continuously evolving HTML spec, which has a comprehensive feature set, that is implemented in a cross-browser interoperable way, has a complete test set for the features, and has received wide review. The latter implies that other groups in the W3C have had a chance to look at the specification and make sure it satisfies their basic requirements, which include e.g. applicability to all users (accessibility, internationalization), platforms, and devices (mobile, TV).

  Basically it means that we stop for a “moment”, take a deep breath, polish the feature set that we’ve been working on this far, and make sure we all agree on it, before we get back to changing the world with cool new stuff. In a software project we would call it a release branch with feature freeze.

  Now, as productive as that may sound for software – it’s not actually that exciting for a specification. Firstly, the most exciting things happen when writing new features. Secondly, development of browsers doesn’t just magically stop to get the release (REC) happening. And lastly, if we’ve done our specification work well, there should be only little work to do. Basically, it’s the unthankful work of tidying up that we’re looking at here.

  So, why am I doing it ? I am not doing this for money – I’m currently part-time contracting to Google’s accessibility team working on video accessibility and this editor work is not covered by my contract. It wasn’t possible to reconcile polishing work on a specification with the goals of my contract, which include pushing new accessibility features forward. Therefore, when invited, I decided to offer my spare time to the W3C.

  I’m giving this time under the condition that I’d only be looking at accessibility and video related sections. This is where my interest and expertise lie, and where I’m passionate to get things right. I want to make sure that we create accessibility features that will be implemented and that we polish existing video features. I want to make sure we don’t digress from implementations which continue to get updated and may follow the WHATWG spec or HTML.next or other needs.

  I am not yet completely sure what the editorship will entail. Will we look at tests, too ? Will we get involved in HTML.next ? This far we’ve been preparing for our work by setting up adequate version control repositories, building a spec creation process, discussing how to bridge to the WHATWG commits, and analysing the long list of bugs to see how to cope with them. There’s plenty of actual text editing work ahead and the team is shaping up well ! I look forward to the new experiences.