Convert Video from Different Formats
You need to have ffmpeg
installed. It's usually installed on linux.
If you don't have ffmpeg
, try avconv
. For some years around 2015, avconv is rename of ffmpeg.
Convert mov to MP4
ffmpeg -f mov -i x.mov x.mp4
Note, .mov is Apple's movie format.
Convert webm to MP4
ffmpeg -f webm -i x.webm x.mp4
Note, .webm is Google's movie format.
Clip a Video
ffmpeg -ss 00:10:05 -i input.mp4 -to 00:13:50 -c copy output.mp4
-ss time_off
- Set the start time offset
-to time_stop
- Record or transcode stop time
Find Out What's Inside a Video Container
“.mp4”, “.mkv” etc are Video/audio container formats. They package together video file, audio files, and other files, of various formats into 1 file.
To find out what's inside, use ffprobe
, e.g.
ffprobe file.mkv
Example output:
~/web/xahmusic_org/music/i $ ffprobe xx.mkv ffprobe version 3.4 Copyright (c) 2007-2017 the FFmpeg developers built with Apple LLVM version 9.0.0 (clang-900.0.37) configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --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, matroska,webm, from 'xx.mkv': Metadata: COMPATIBLE_BRANDS: iso6avc1mp41 MAJOR_BRAND : dash MINOR_VERSION : 0 ENCODER : Lavf57.83.100 Duration: 00:05:04.90, start: 0.000000, bitrate: 1329 kb/s Stream #0:0: Video: h264 (Main), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default) Metadata: HANDLER_NAME : VideoHandler DURATION : 00:05:04.871000000 Stream #0:1(eng): Audio: vorbis, 44100 Hz, stereo, fltp (default) Metadata: DURATION : 00:05:04.903000000

Put a Opus Audio into a .Webm Container
ffmpeg -i x.opus -c:a copy x.webm
Add Opus Audio into Existing Webm
ffmpeg -i y.webm -i x.opus -c:v copy -c:a copy x.webm
Extract Audio from Video
extract audio file inside file x.mp4 and name it x.m4a
ffmpeg -i x.mp4 -vn -acodec copy x.m4a
ffmpeg -f mp4 -i x.mp4 -vn -c:a copy x.m4a
or
ffmpeg -f mp4 -i x.mp4 -map 0:1 -c:a copy x.m4a
-map 0:1 means stream number 1 from file number 0, which would usually be the audio track (edit as necessary). specifying a map at all disables the default map which would be to copy every stream, so you get only the audio, not both. -c:a copy means just copy it, no re-encoding. You may also want to specify a -f for the output to choose a container fomat; I am not sure what it will use by default, probably the same as the input.
2018-11-26 thanks to harvhat https://noagendasocial.com/@harvhat and matthew skala https://mstdn.io/web/accounts/18568
syntax of ffmpeg
The general syntax of ffmpeg is:
ffmpeg options infile_options -i infileName outfile_options outfileName
-f fmt
- force format fmt
ffmpeg manual
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/bsf 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 -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 -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 maximum error rate ratio of errors (0.0: no errors, 1.0: 100% errors) above which ffmpeg returns an error instead of success. -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