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• 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.

• Why I became a HTML5 co-editor

  1er janvier 2014, 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.

• ffmpeg concat vertical video, different dimensions [duplicate]

  16 octobre 2020, par Morris

  Context :
3 input videos :

  


  foo.mov : 1080x1920 (vertical, NOT horizontal) with audio.

  


  bar.mp4 and fiz.mp4 : 480x360, with audio.
(Note : .mp4, differs from .mov)

  


  Goal : to concat all 3 videos. Output out.mp4 should be 480x360. Squeeze foo.mov but keep its aspect ratio, taking up 100% height, but the slim video should stand only in the center, with left and right sides being black (or other color) void. foo.mov should not be cropped.

  


  I currently have this command below (added new-line characters for better visualization) for concating, but need to fill the missing code at PLACEHOLDER1 to generate v0, such that v0 is resized to 480x360 like described above. If my attempt so far is correct, please help complete PLACEHOLDER1 ; else, please offer a better solution with explanation.

  


  ffmpeg 
-r 24 -i foo.mov 
-r 24 -i bar.mp4 
-r 24 -i fiz.mp4
-filter_complex 
"[0:v] PLACEHOLDER1 [v0];
[v0][1][2] concat=n=3:v=1:a=1 [v][a]" 
-map "[v]" -map "[a]" out.mp4


  


  Running

  


  ffmpeg -n -i foo.MOV -i bar.mp4 -i fiz.mp4


  


  gives this info :

  


  ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 11.0.3 (clang-1103.0.32.62)
  [...configuration omitted...]
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'foo.MOV':
  Metadata:
    major_brand     : qt  
    minor_version   : 0
    compatible_brands: qt  
    creation_time   : [omitted]
    com.apple.quicktime.make: [omitted]
    com.apple.quicktime.model: [omitted]
    com.apple.quicktime.software: [omitted]
    com.apple.quicktime.creationdate: [omitted]
  Duration: 00:00:04.71, start: 0.000000, bitrate: 17579 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 17492 kb/s, 24 fps, 24 tbr, 600 tbn, 1200 tbc (default)
    Metadata:
      rotate          : 90
      creation_time   : [omitted]
      handler_name    : Core Media Video
      encoder         : H.264
    Side data:
      displaymatrix: rotation of -90.00 degrees
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s (default)
    Metadata:
      creation_time   : [omitted]
      handler_name    : Core Media Audio
    Stream #0:2(und): Data: none (mebx / 0x7862656D), 9 kb/s (default)
    Metadata:
      creation_time   : [omitted]
      handler_name    : Core Media Metadata
    Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : [omitted]
      handler_name    : Core Media Metadata

Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'bar.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:01.94, start: 0.000000, bitrate: 641 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, smpte170m/unknown/smpte170m), 480x360 [SAR 1:1 DAR 4:3], 354 kb/s, 24.58 fps, 24.58 tbr, 113734695.00 tbn, 49.16 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 280 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'fiz.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:01.98, start: 0.000000, bitrate: 725 kb/s
    Stream #2:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, smpte170m/unknown/smpte170m), 480x360 [SAR 1:1 DAR 4:3], 442 kb/s, 24.58 fps, 24.58 tbr, 113734695.00 tbn, 49.16 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #2:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 278 kb/s (default)
    Metadata:
      handler_name    : SoundHandler