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• Is there a way to use InputStream to get the media details

  13 mai 2019, par Naman

  I am currently accepting InputStream from a client of my server for a File uploaded via multipart/form-data.

  I am currently using ffmpeg-cli-wrapper library to use ffprobe and ffmpeg.

  The challenge I see up front is that the APIs exposed by the client doesn’t make use of a stream, rather a mediaPath. Is there a way/library similar to this which can provide me an FFProbe instance as shown in the usage example of the library.

  To add to the pain, I am aware of transforming the InputStream into a file and then passing the mediaPath. But that’s an unnecessary space on my processing disk and an additional step for cleanup as well.

• Metadata in mp3 not working when piping from ffmpeg with album art

  10 février 2019, par Cromon

  In my program I am piping a webm from a stream to ffmpeg and then pipe the output to a http request. Part of the process is adding metadata for the mp3. This has so far worked great. However after adding an image as album art it has started to act unexpected.

  First this is the command line I am using inside the program :

      val parameters = listOf("ffmpeg",
  
              "-i", "-",
  
              "-i", albumImage.absolutePath,
  
              "-map", "0",
  
              "-map", "1",
  
              "-c:v", "copy",
  
              "-f", "mp3",
  
              "-id3v2_version", "4",
  
              "-metadata", "title=${info.title}",
  
              "-metadata", "album=YouTube",
  
              "-metadata", "artist=${info.author}",
  
              "-metadata:s:v", "title=Album Cover",
  
              "-metadata:s:v", "comment=Cover (front)",
  
              "-"
  
      )

  It creates a valid mp3 file and I can find both the metadata and the image in the mp3 file, however when playing it none of them are displayed in VLC or anywhere else. To test various configurations I have converted it to the command line.

  In a first try I have saved the video and the image and stopped using pipes altogether, which results in this :

  ffmpeg -i video.webm -i image.jpeg -map 0 -map 1 -c:v copy -f mp3 -id3v2_version 4 -metadata title="Tiësto & KSHMR feat. Vassy - Secrets (Official Music Video)" -metadata album="YouTube" -metadata artist="Spinnin' Records" -metadata:s:v title="Album Cover" -metadata:s:v comment="Cover (front)" output3.mp3

  In this case all metadata including the album art is displayed in VLC.

  I then recreated the same thing as in my program, piping both video input and audio output, looking like this :

  ffmpeg -i - -i image.jpeg -map 0 -map 1 -c:v copy -f mp3 -id3v2_version 4 -metadata title="Tiësto & KSHMR feat. Vassy - Secrets (Official Music Video)" -metadata album="YouTube" -metadata artist="Spinnin' Records" -metadata:s:v title="Album Cover" -metadata:s:v comment="Cover (front)" - < video.webm > output3.mp3

  This file is the same as my programs output. Neither title nor album nor album image are displayed (however it can play the file)

  To test a few more options I have hardcoded the output file but pipe the input file like this :

  ffmpeg -i - -i image.jpeg -map 0 -map 1 -c:v copy -f mp3 -id3v2_version 4 -metadata title="Tiësto & KSHMR feat. Vassy - Secrets (Official Music Video)" -metadata album="YouTube" -metadata artist="Spinnin’ Records" -metadata:s:v title="Album Cover" -metadata:s:v comment="Cover (front)" output3.mp3 < video.webm

  Now the metadata is working again. When hardcoding the input video and piping the output, its again gone.

  So to sum up : When piping the output of ffmpeg the metadata in the file is not properly working. Interestingly the stderr output of ffmpeg looks quite similar

  Hardcoded output3.mp3 :

  ffmpeg version 3.4.4-0ubuntu0.18.04.1 Copyright (c) 2000-2018 the FFmpeg developers
  
  Input #0, matroska,webm, from 'pipe:':
  
    Metadata:
  
      encoder         : google/video-file
  
    Duration: 00:03:39.58, start: -0.007000, bitrate: N/A
  
      Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
  
  Input #1, image2, from 'image.jpeg':
  
    Duration: 00:00:00.04, start: 0.000000, bitrate: 1466 kb/s
  
      Stream #1:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 320x180, 25 tbr, 25 tbn, 25 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (opus (native) -> mp3 (libmp3lame))
  
    Stream #1:0 -> #0:1 (copy)
  
  Output #0, mp3, to 'output3.mp3':
  
    Metadata:
  
      TPE1            : Spinnin' Records
  
      TIT2            : Tiësto & KSHMR feat. Vassy - Secrets (Official Music Video)
  
      TALB            : YouTube
  
      TSSE            : Lavf57.83.100
  
      Stream #0:0(eng): Audio: mp3 (libmp3lame), 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        encoder         : Lavc57.107.100 libmp3lame
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 320x180, q=2-31, 25 tbr, 25 tbn, 25 tbc
  
      Metadata:
  
        title           : Album Cover
  
        comment         : Cover (front)

  With pipe output :

  ffmpeg version 3.4.4-0ubuntu0.18.04.1 Copyright (c) 2000-2018 the FFmpeg developers
  
  Input #0, matroska,webm, from 'pipe:':
  
    Metadata:
  
      encoder         : google/video-file
  
    Duration: 00:03:39.58, start: -0.007000, bitrate: N/A
  
      Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
  
  Input #1, image2, from 'image.jpeg':
  
    Duration: 00:00:00.04, start: 0.000000, bitrate: 1466 kb/s
  
      Stream #1:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 320x180, 25 tbr, 25 tbn, 25 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (opus (native) -> mp3 (libmp3lame))
  
    Stream #1:0 -> #0:1 (copy)
  
  Output #0, mp3, to 'pipe:':
  
    Metadata:
  
      TPE1            : Spinnin' Records
  
      TIT2            : Tiësto & KSHMR feat. Vassy - Secrets (Official Music Video)
  
      TALB            : YouTube
  
      TSSE            : Lavf57.83.100
  
      Stream #0:0(eng): Audio: mp3 (libmp3lame), 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        encoder         : Lavc57.107.100 libmp3lame
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 320x180, q=2-31, 25 tbr, 25 tbn, 25 tbc
  
      Metadata:
  
        title           : Album Cover
  
        comment         : Cover (front)

• Problems in compiling x86 ASM in ffmpeg to WebAssembly

  18 février 2019, par Sparkmorry

  sorry I’m new to wasm and working on a project decoding videos on browser with ffmpeg and WebAssembly(wasm) to improve the performance. I have used Emscripten(emcc) to compile ffmpeg to wasm and got things worked.
  However, as Emscripten cannot compile inline assembly code, video decoding with wasm on web is almost 3-5 times slower than native decoding without asm supported, and the cpu usage could be really high. As far as I know, wasm is a stack-based vm while asm is cpu specific, but without asm, wasm is quite far from the aim to native speed.
  After some day searching on the basic concept of wasm and asm etc. I have known some compiler like nasm to perform cross-platform asm, can I have some compiler front to have llvmir and asm instructions together to have asm-supported in wasm ?