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• Is there a method to identify the audio channel layout ?

  2 septembre 2016, par Pony

  A video file has many channels, and each channel is contained in a stream, e.g.

  libavutil      52. 38.100 / 52. 38.100
  
  libavcodec     55. 18.102 / 55. 18.102
  
  libavformat    55. 12.100 / 55. 12.100
  
  libavdevice    55.  3.100 / 55.  3.100
  
  libavfilter     3. 79.101 /  3. 79.101
  
  libswscale      2.  3.100 /  2.  3.100
  
  libswresample   0. 17.102 /  0. 17.102
  
  libpostproc    52.  3.100 / 52.  3.100
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Guessed Channel Layout for  Input Stream #0.2 : mono
  
  Guessed Channel Layout for  Input Stream #0.3 : mono
  
  Guessed Channel Layout for  Input Stream #0.4 : mono
  
  Guessed Channel Layout for  Input Stream #0.5 : mono
  
  Guessed Channel Layout for  Input Stream #0.6 : mono
  
  Guessed Channel Layout for  Input Stream #0.7 : mono
  
  Guessed Channel Layout for  Input Stream #0.8 : mono
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/data/tmp/ff6.mov':
  
  Metadata:
  
  major_brand     : qt  
  
  minor_version   : 537199360
  
  compatible_brands: qt  
  
  creation_time   : 2015-01-16 17:54:47
  
  Duration: 00:01:54.00, start: 0.000000, bitrate: 160836 kb/s
  
  Stream #0:0(eng): Video: prores (apch / 0x68637061), yuv422p10le, 1920x1080, 154650 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
    timecode        : 00:59:55:00
  
  Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:2(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:3(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:4(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:5(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:6(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:7(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:8(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16, 768 kb/s
  
  Metadata:
  
    creation_time   : 2015-01-16 17:54:47
  
    handler_name    : Apple Alias Data Handler
  
  Stream #0:9(eng): Data: none (tmcd / 0x64636D74)
  
  Metadata:
  
    creation_time   : 2015-01-16 17:55:17
  
    handler_name    : Apple Alias Data Handler
  
    timecode        : 00:59:55:00

  Is there a method to identify which stream represents the left channel, and which represent right channel, and so on.
  Thanks for reviewing my question.

• ffmpeg : How to create multi playlist m3u8 ?

  21 août 2018, par noc

  I have an example :

  ffmpeg -loglevel debug -threads 4 -vsync 1 -i 'bunny.mp4' -vf yadif -g 29.97 -r 29.97 -b:v:0 5250k -c:v h264_nvenc -preset llhq -vcodec vbr_hq -pix_fmt yuv420p -profile:v main -level 4.1 -strict_gop 1 -rc-lookahead 32 -no-scenecut 1 -forced-idr 1 -gpu 0 -b:v:1 4200k -c:v h264_nvenc -preset llhq -rc:v vbr_hq -pix_fmt yuv420p -profile:v main -level 4.1 -strict_gop 1 -rc-lookahead 32 -no-scenecut 1 -forced-idr 1 -gpu 1 -b:v:1 3150k -c:v h264_nvenc -preset llhq -rc:v vbr_hq -pix_fmt yuv420p -profile:v main -level 4.1 -strict_gop 1 -rc-lookahead 32 -no-scenecut 1 -forced-idr 1 -gpu 2 -b:a:0 256k -b:a:0 192k -b:a:0 128k -c:a aac -ar 48000  -map 0:v -map 0:a:0 -map 0:v -map 0:a:0 -map 0:v -map 0:a:0 -f hls -var_stream_map "v:0,a:0  v:1,a:1 v:2,a:2" -master_pl_name  master.m3u8 -t 300 -hls_time 10 -hls_init_time 4 -hls_list_size 10 -master_pl_publish_rate 10 -hls_flags delete_segments+discont_start+split_by_time "out/manifest.m3u8" 

  but alltime a have error like :
  Unrecognized option ’rc:v’
  Unrecognized option ’strict_gop’

  I’d like to create the playlist like this :

  #EXTM3U
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=688301
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/0640_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=165135
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/0150_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=262346
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/0240_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=481677
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/0440_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=1308077
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/1240_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=1927853
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/1840_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=2650941
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/2540_vod.m3u8
  
  #EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=3477293
  
  http://qthttp.apple.com.edgesuite.net/1010qwoeiuryfg/3340_vod.m3u8

  with ability to choose quality in player (videojs)

• Seeking Guidance on Audio Development Libraries for Playing Various Music Formats on iOS [closed]

  3 décembre 2023, par FaiChou

  I am exploring audio development and am overwhelmed by the numerous libraries available :

  


  

  • AVFoundation

  


  • MediaPlayer

  


  • AVFAudio

  


  • Audio Engine

  


  • CoreAudio

  


  • AudioToolbox

  


  • Audio Unit

  


  


  Which of these should I use to play both network or local music files (flac/wav/mp3/aac/wma/ogg) ? What are their specific roles ?

  


  My understanding is that I should use ffmpeg for demuxing to unpackage, then decode the stream to get PCM samples, possibly using Audio Engine for playback. Is this a software decoding method ? For Apple-supported formats like mp3, can I bypass ffmpeg for decoding ? Which library would be most suitable in this case ?

  


  Additionally, how do I extract metadata (song name, artist, cover, lyrics, etc.) from music files ? Apple's own solutions seem to support only ID3 or iTunes tags. How should I handle other formats like wav/flac ?

  


  The two links below are the resources I've referenced, but they seem outdated. My search for newer, reliable explanations has been fruitless.

  


  

  • whats-the-difference-between-the-apple-audio-frameworks

  


  • Core Audio Essentials