流畅的 ffmpeg 大小输出选项不起作用

Question

总结：我正在尝试将输出限制为 3mb，.outputOptions('-fs 3000000') 对我不起作用，返回的文件大小为 119260428 或 119mb。

这是您自己尝试的代码，您只需要 test.mp3 足够大，使得结果 testoutput.ogg > 3mb:

var ffmpeg = require("fluent-ffmpeg");
var command = ffmpeg();

var convertToOGG = function(){
  var fileName = 'test.mp3'

  ffmpeg.ffprobe(fileName, function(err, metadata) {
    command
      .input(fileName)
      .inputFormat("mp3")
      .audioChannels(1)
      .outputOptions('-fs', 3000000)
      .output('testoutput.ogg')
      .on("progress", function(progress) {
        console.log("Processing: " + progress.timemark);
      })
      .on("error", function(err, stdout, stderr) {
        console.log("Cannot process video: " + err.message);
      })
      .on("end", function(stdout, stderr) {
        ffmpeg.ffprobe('testoutput.ogg', function(err,metadata){
          if(metadata.format.size >= 3000000){

            console.log("didn't work")
          } 
        })
      })
    .run();
  });
};

convertToOGG();

根据 fluent-ffmpeg documentation，您应该能够在输出选项中使用 ffmpeg 命令：outputOption()

This method allows passing any output-related option to ffmpeg. You can call it with a single argument to pass a single option, optionnaly with a space-separated parameter:

/* Single option */
ffmpeg('/path/to/file.avi').outputOptions('-someOption');

and in FFMPEG's documentation:

-fs limit_size (output) Set the file size limit, expressed in bytes. No further chunk of bytes is written after the limit is exceeded. The size of the output file is slightly more than the requested file size.

它没有给我任何错误，只是似乎忽略了 99mb 的文件大小限制并输出了一个 119.3mb 的文件。

编辑 - 看起来 -fs 3000000 正在将 mp3 转换为 wav，但仍然无法将 mp3 转换为 ogg。这是运行终端命令的输出：

✗ ffmpeg -i test.mp3 -fs 3000000 testoutput.ogg
ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
  built with Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  libavutil      55. 34.100 / 55. 34.100
  libavcodec     57. 64.101 / 57. 64.101
  libavformat    57. 56.100 / 57. 56.100
  libavdevice    57.  1.100 / 57.  1.100
  libavfilter     6. 65.100 /  6. 65.100
  libavresample   3.  1.  0 /  3.  1.  0
  libswscale      4.  2.100 /  4.  2.100
  libswresample   2.  3.100 /  2.  3.100
  libpostproc    54.  1.100 / 54.  1.100
[mp3 @ 0x7fc6a4000000] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'test.mp3':
  Metadata:
    lyrics-eng      : xxx
    title           : xxx
    artist          : xxx
    album_artist    : xxx
    album           : xxx
    genre           : xxx
  Duration: 03:27:28.74, start: 0.000000, bitrate: 128 kb/s
    Stream #0:0: Audio: mp3, 44100 Hz, mono, s16p, 128 kb/s
    Stream #0:1: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 540x360, 90k tbr, 90k tbn, 90k tbc
    Metadata:
      title           : Array
      comment         : Cover (front)
[swscaler @ 0x7fc6a4808800] deprecated pixel format used, make sure you did set range correctly
[ogg @ 0x7fc6a3815800] Frame rate very high for a muxer not efficiently supporting it.
Please consider specifying a lower framerate, a different muxer or -vsync 2
Output #0, ogg, to 'testoutput.ogg':
  Metadata:
    lyrics-eng      : xxx
    title           : xxx
    artist          : xxx
    album_artist    : xxx
    album           : xxx
    genre           : xxx
    encoder         : Lavf57.56.100
    Stream #0:0: Video: theora (libtheora), yuv444p, 540x360, q=2-31, 200 kb/s, 90k fps, 90k tbn, 90k tbc
    Metadata:
      title           : Array
      DESCRIPTION     : Cover (front)
      encoder         : Lavc57.64.101 libtheora
      lyrics-eng      : xxx
      artist          : xxx
      ALBUMARTIST     : xxx
      album           : xxx
      genre           : xxx
    Stream #0:1: Audio: vorbis (libvorbis), 44100 Hz, mono, fltp
    Metadata:
      encoder         : Lavc57.64.101 libvorbis
      lyrics-eng      : xxx
      title           : xxx
      artist          : xxx
      ALBUMARTIST     : xxx
      album           : xxx
      genre           : xxx
Stream mapping:
  Stream #0:1 -> #0:0 (mjpeg (native) -> theora (libtheora))
  Stream #0:0 -> #0:1 (mp3 (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=-0.0 Lsize=  116465kB time=03:27:28.71 bitrate=  76.6kbits/s speed=61.2x
video:9kB audio:114907kB subtitle:0kB other streams:0kB global headers:6kB muxing overhead: 1.347787%

Answer 1

来源 mp3 包含封面图片。尝试将源文件转码为 ogg 会导致视频流的帧率异常高。

帧率估计有问题：90k fps类似于流时基值：

[ogg @ 0x7fc6a3815800] Frame rate very high for a muxer not efficiently supporting it.
[...]
Stream #0:0: Video: theora (libtheora), yuv444p, 540x360, q=2-31, 200 kb/s, 90k fps, 90k tbn, 90k tbc

这可能是由源文件问题、ffmpeg 中的错误或两者共同引起的。

一个快速的解决方案是使用 -map 0:a 或 -vn 忽略封面图片。

流畅的 ffmpeg 大小输出选项不起作用

fluent ffmpeg size output option not working

ffmpeg

node.js

fluent-ffmpeg