如何使用Windows命令行中的ffmpeg將MP3轉換爲AMR

Question

使用基於Windows的ffmpeg將MP3轉換爲AMR。 出於某種原因，它失敗，錯誤如下。

不知道如何爲AMR提供正確的參數。

C:\Program Files (x86)\AMR to MP3 Converter>ffmpeg -i mfile.mp3 -ar 8000 -ab 12.2k audio.amr 
FFmpeg version SVN-r26400, Copyright (c) 2000-2011 the FFmpeg developers 
    built on Jan 18 2011 04:07:05 with gcc 4.4.2 
    configuration: --enable-gpl --enable-version3 --enable-libgsm --enable-libvorb 
is --enable-libtheora --enable-libspeex --enable-libmp3lame --enable-libopenjpeg 
--enable-libschroedinger --enable-libopencore_amrwb --enable-libopencore_amrnb 
--enable-libvpx --disable-decoder=libvpx --arch=x86 --enable-runtime-cpudetect - 
-enable-libxvid --enable-libx264 --enable-librtmp --extra-libs='-lrtmp -lpolarss 
l -lws2_32 -lwinmm' --target-os=mingw32 --enable-avisynth --enable-w32threads -- 
cross-prefix=i686-mingw32- --cc='ccache i686-mingw32-gcc' --enable-memalign-hack 

    libavutil  50.36. 0/50.36. 0 
    libavcore  0.16. 1/0.16. 1 
    libavcodec 52.108. 0/52.108. 0 
    libavformat 52.93. 0/52.93. 0 
    libavdevice 52. 2. 3/52. 2. 3 
    libavfilter 1.74. 0/1.74. 0 
    libswscale  0.12. 0/0.12. 0 
[mp3 @ 003abeb0] max_analyze_duration reached 
[mp3 @ 003abeb0] Estimating duration from bitrate, this may be inaccurate 
Input #0, mp3, from 'mfile.mp3': 
    Metadata: 
    title   : SPL_TRACK 
    artist   : Krishnan 
    album   : Lord 
    genre   : Lord 
    track   : 5 
    Duration: 00:30:06.00, start: 0.000000, bitrate: 127 kb/s 
    Stream #0.0: Audio: mp3, 44100 Hz, 2 channels, s16, 128 kb/s 
[libopencore_amrnb @ 017e0d20] Only mono supported 
Output #0, amr, to 'audio.amr': 
    Stream #0.0: Audio: libopencore_amrnb, 8000 Hz, 2 channels, s16, 12 kb/s 
Stream mapping: 
    Stream #0.0 -> #0.0 
Error while opening encoder for output stream #0.0 - maybe incorrect parameters 
such as bit_rate, rate, width or height 

Answer 1

由於錯誤味精說：Only mono supported，所以加-ac 1。

無論如何，你的ffmpeg是史前的。從https://ffmpeg.zeranoe.com/builds/得到一個新的二進制