折腾：
【已解决】用Python代码从视频中提取出音频mp3文件
期间，在写python代码调用ffmpeg之前，先要去终端中确保用法正确。
先看看用法：
➜ 61264527 which ffmpeg
/usr/local/bin/ffmpeg
➜ 61264527 ffmpeg --help
ffmpeg version 3.4.2 Copyright (c) 2000-2018 the FFmpeg developers
built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --disable-jack --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
libavutil 55. 78.100 / 55. 78.100
libavcodec 57.107.100 / 57.107.100
libavformat 57. 83.100 / 57. 83.100
libavdevice 57. 10.100 / 57. 10.100
libavfilter 6.107.100 / 6.107.100
libavresample 3. 7. 0 / 3. 7. 0
libswscale 4. 8.100 / 4. 8.100
libswresample 2. 9.100 / 2. 9.100
libpostproc 54. 7.100 / 54. 7.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
Getting help:
-h -- print basic options
-h long -- print more options
-h full -- print all options (including all format and codec specific options, very long)
-h type=name -- print all options for the named decoder/encoder/demuxer/muxer/filter
See man ffmpeg for detailed description of the options.
Print help / information / capabilities:
-L show license
-h topic show help
-? topic show help
-help topic show help
--help topic show help
-version show version
-buildconf show build configuration
-formats show available formats
-muxers show available muxers
-demuxers show available demuxers
-devices show available devices
-codecs show available codecs
-decoders show available decoders
-encoders show available encoders
-bsfs show available bit stream filters
-protocols show available protocols
-filters show available filters
-pix_fmts show available pixel formats
-layouts show standard channel layouts
-sample_fmts show available audio sample formats
-colors show available color names
-opencl_bench run benchmark on all OpenCL devices and show results
-sources device list sources of the input device
-sinks device list sinks of the output device
-hwaccels show available HW acceleration methods
Global options (affect whole program instead of just one file:
-loglevel loglevel set logging level
-v loglevel set logging level
-report generate a report
-max_alloc bytes set maximum size of a single allocated block
-opencl_options set OpenCL environment options
-y overwrite output files
-n never overwrite output files
-ignore_unknown Ignore unknown stream types
-filter_threads number of non-complex filter threads
-filter_complex_threads number of threads for -filter_complex
-stats print progress report during encoding
-max_error_rate ratio of errors (0.0: no errors, 1.0: 100% error maximum error rate
-bits_per_raw_sample number set the number of bits per raw sample
-vol volume change audio volume (256=normal)
Per-file main options:
-f fmt force format
-c codec codec name
-codec codec codec name
-pre preset preset name
-map_metadata outfile[,metadata]:infile[,metadata] set metadata information of outfile from infile
-t duration record or transcode "duration" seconds of audio/video
-to time_stop record or transcode stop time
-fs limit_size set the limit file size in bytes
-ss time_off set the start time offset
-sseof time_off set the start time offset relative to EOF
-seek_timestamp enable/disable seeking by timestamp with -ss
-timestamp time set the recording timestamp ('now' to set the current time)
-metadata string=string add metadata
-program title=string:st=number... add program with specified streams
-target type specify target file type ("vcd", "svcd", "dvd", "dv" or "dv50" with optional prefixes "pal-", "ntsc-" or "film-")
-apad audio pad
-frames number set the number of frames to output
-filter filter_graph set stream filtergraph
-filter_script filename read stream filtergraph description from a file
-reinit_filter reinit filtergraph on input parameter changes
-discard discard
-disposition disposition
Video options:
-vframes number set the number of video frames to output
-r rate set frame rate (Hz value, fraction or abbreviation)
-s size set frame size (WxH or abbreviation)
-aspect aspect set aspect ratio (4:3, 16:9 or 1.3333, 1.7777)
-bits_per_raw_sample number set the number of bits per raw sample
-vn disable video
-vcodec codec force video codec ('copy' to copy stream)
-timecode hh:mm:ss[:;.]ff set initial TimeCode value.
-pass n select the pass number (1 to 3)
-vf filter_graph set video filters
-ab bitrate audio bitrate (please use -b:a)
-b bitrate video bitrate (please use -b:v)
-dn disable data
Audio options:
-aframes number set the number of audio frames to output
-aq quality set audio quality (codec-specific)
-ar rate set audio sampling rate (in Hz)
-ac channels set number of audio channels
-an disable audio
-acodec codec force audio codec ('copy' to copy stream)
-vol volume change audio volume (256=normal)
-af filter_graph set audio filters
Subtitle options:
-s size set frame size (WxH or abbreviation)
-sn disable subtitle
-scodec codec force subtitle codec ('copy' to copy stream)
-stag fourcc/tag force subtitle tag/fourcc
-fix_sub_duration fix subtitles duration
-canvas_size size set canvas size (WxH or abbreviation)
-spre preset set the subtitle options to the indicated preset
然后继续参考：
的
./ffmpeg -i DeadPoetsSocietyCD1.avi -ss 00:00:00.000 -to 00:02:00.000 -b:a 128k output.mp3
先去看看对应参数含义
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
-ss time_off set the start time offset
-to time_stop record or transcode stop time
-ab bitrate audio bitrate (please use -b:a)去试试
➜ 157712932 ll total 10192 -rw-r--r-- 1 crifan staff 1.7K 9 26 15:28 show_157712932_info.json -rw-r--r-- 1 crifan staff 5.0M 9 26 15:27 show_157712932_video.mp4 ➜ 157712932 ffmpeg -i show_157712932_video.mp4 -ss 00:00:11.270 -to 00:00:14.550 -b:a 128k show_157712932_audio_000011270_000014550.mp3 ffmpeg version 3.4.2 Copyright (c) 2000-2018 the FFmpeg developers built with Apple LLVM version 9.0.0 (clang-900.0.39.2) configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --disable-jack --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma libavutil 55. 78.100 / 55. 78.100 libavcodec 57.107.100 / 57.107.100 libavformat 57. 83.100 / 57. 83.100 libavdevice 57. 10.100 / 57. 10.100 libavfilter 6.107.100 / 6.107.100 libavresample 3. 7. 0 / 3. 7. 0 libswscale 4. 8.100 / 4. 8.100 libswresample 2. 9.100 / 2. 9.100 libpostproc 54. 7.100 / 54. 7.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'show_157712932_video.mp4': Metadata: major_brand : isom minor_version : 0 compatible_brands: isomiso2avc1 creation_time : 2018-09-25T14:26:33.000000Z Duration: 00:01:05.45, start: 0.000000, bitrate: 637 kb/s Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 573 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 60 kb/s (default) Metadata: creation_time : 2018-09-25T14:26:33.000000Z Stream mapping: Stream #0:1 -> #0:0 (aac (native) -> mp3 (libmp3lame)) Press [q] to stop, [?] for help Output #0, mp3, to 'show_157712932_audio_000011270_000014550.mp3': Metadata: major_brand : isom minor_version : 0 compatible_brands: isomiso2avc1 TSSE : Lavf57.83.100 Stream #0:0(eng): Audio: mp3 (libmp3lame), 44100 Hz, stereo, fltp, 128 kb/s (default) Metadata: creation_time : 2018-09-25T14:26:33.000000Z encoder : Lavc57.107.100 libmp3lame size= 52kB time=00:00:03.29 bitrate= 130.3kbits/s speed=36.6x video:0kB audio:52kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.053127% ➜ 157712932 ll total 10304 -rw-r--r-- 1 crifan staff 52K 10 4 10:35 show_157712932_audio_000011270_000014550.mp3 -rw-r--r-- 1 crifan staff 1.7K 9 26 15:28 show_157712932_info.json -rw-r--r-- 1 crifan staff 5.0M 9 26 15:27 show_157712932_video.mp4 ➜ 157712932
【总结】
用
ffmpeg -i show_157712932_video.mp4 -ss 00:00:11.270 -to 00:00:14.550 -b:a 128k show_157712932_audio_000011270_000014550.mp3
其中各个参数的含义是：
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
-ss time_off set the start time offset
-to time_stop record or transcode stop time
-ab bitrate audio bitrate (please use -b:a)可以从mp4中提取出我们需要的mp3的：
转载请注明：在路上 » 【已解决】Mac中用ffmpeg从mp4视频中提取mp3音频