ffmpeg - 将 PCM 音频复用到 WMA 会显着增加文件大小

Question

虽然我试图将 wav 文件转换为 wma 文件大小变得比原始源文件大得多:

input.wav - 11M

output.wma - 16M

有什么办法可以减少输出文件的文件大小？

命令和输出:

$ ffmpeg -i input.wav -c copy output.wma

ffmpeg version N-80797-g8b4d6cc Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 6.1.1 (GCC) 20160501
  configuration: --enable-gpl
  libavutil      55. 27.100 / 55. 27.100
  libavcodec     57. 48.101 / 57. 48.101
  libavformat    57. 40.101 / 57. 40.101
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 46.102 /  6. 46.102
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, wav, from 'input.wav':
  Metadata:
    encoder         : Lavf57.40.101
  Duration: 00:01:00.00, bitrate: 1411 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 2 channels, s16, 1411 kb/s
Output #0, asf, to 'output.wma':
  Metadata:
    WM/EncodingSettings: Lavf57.40.101
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, 1411 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
size=   16150kB time=00:01:00.00 bitrate=2205.1kbits/s speed=1.9e+03x    
video:0kB audio:10336kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 56.255745%

Answer 1

WMA 很烂。尝试更改数据包大小。来自 FFmpeg ASF muxer documentation :

-packet_size
Set the muxer packet size. By tuning this setting you may reduce data fragmentation or muxer overhead depending on your source. Default value is 3200, minimum is 100, maximum is 64k.

例子:

ffmpeg -i input.wav -c copy -packet_size 65536 output_64k.wma

文件大小:

input.wav - 11M

output_64k.wma - 11M

output_default.wma - 16M