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• AR Drone 2.0 video streaming whitout SDK on iOS

  10 janvier 2014, par JosephITA

  I'm coding an app for iOS that interact with the AR Drone 2.0 without using the SDK (poor documentation on the iPhone example).
  At the moment I can send command and receive navdata.
  I have no idea in how to receive video streaming. I know that is an H.264 stream and that I can use ffmpeg, but I'm not sure that this solution will pass the Apple revision.
  Any ideas ?

• 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


  


• avformat/isom : lpcm in mov default to big endian

  1er novembre 2013, par Mark Himsley

  avformat/isom : lpcm in mov default to big endian
  It is my understanding that "Unless otherwise stated, all data in a
  
  QuickTime movie is stored in big-endian byte ordering" [1] in MOV files.
  I have a couple of thousand files, which technically are invalid because
  
  their sound sample description element 4CC is ’lpcm’ but its version is
  
  0 - and "Version 0 supports only uncompressed audio in raw (’raw ’) or
  
  twos-complement (’twos’) format" [2]
  Because isom.c only contains a mapping for 4CC ’lpcm’ to
  
  AV_CODEC_ID_PCM_S16LE, these files have their audio decoded as LE when
  
  it is actually BE.
  This commit adds AV_CODEC_ID_PCM_S16BE as the first match for 4CC ’lpcm’.
  [1]
  
  https://developer.apple.com/library/mac/documentation/quicktime/QTFF/qtff.pdf
  
  page 21
  
  [2]
  
  https://developer.apple.com/library/mac/documentation/quicktime/QTFF/qtff.pdf
  
  page 178
  Reviewed-by : Yusuke Nakamura <muken.the.vfrmaniac@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/isom.c