目录
- help命令使用
- 流选择选项
- 视频封装解封装
- 3.1 视频格式转换
- 3.2 分离/合并视频音频流
- 3.3 截取视频片段
- 3.4 视频转换为m3u8格式
- 3.5 把视频文件推送到rtmp服务器
- 3.6 对视频进行切片
- 视频解码编码
- 4.1 视频截图
- 4.2 视频/图片尺寸修改
- 4.3 分离视频的YUV通道分量
- 4.4 图片序列与视频的互相转换
- 4.5 yuv压缩为264 MP4文件
- 视频filter
- 5.1 视频加水印overlay
- 5.2 视频旋转transpose
- 5.3 调色3DLutFilter
- 5.4 图像/视频转换成黑白的hue
- 5.5 裁剪视频crop
- 5.6 视频尺寸缩放scale
- 5.7 视频中去水印delogo
- 5.8 给视频或图像加上黑边pad
- 5.9 计算psnr/ssim
- 5.10 视频按时间拼接
- 5.11 视频左右拼接
- 5.12 打印视频帧的一些信息showinfo
- 5.13 生成纯色的图片
- 5.14 打印帧序号/pts到视频帧水印drawtext
- 音频解码编码
- 6.1 PCM原始数据和WAV格式转换
- 音频filter
- 7.1 倍速atempo
- 字幕相关
- 8.1 字幕文件转换
- 8.2 集成字幕到视频文件
- ffplay命令
- 9.1 ffplay播放yuv视频数据
- 9.2 ffplay播放PCM音频数据
- 9.3 ffplay播放音频并显示波形图
- 9.4 ffplay指定显示宽高
- ffprobe命令
- 10.1 ffprobe查看媒体文件的信息
- 10.2 ffprobe查看时间戳
- 10.3 ffprobe查看每帧的帧类型信息
- 其他
- 11.1 ffmpeg或ffplay 打开 DEBUG 日志输出
- 11.2 FFmpeg命令日志输出到文件
- 11.3 打印支持DirectShow的设备列表
参考
1. help命令使用
首先我们要学会使用ffmpeg工具提供的最最基本的一个命令：ffmpeg -help。
有了他我们就可以更加愉快地学习使用ffmpeg的各种功能了。
执行ffmpeg -help后，在终端会打印下面的帮助信息：
ffmpeg version 3.4.2-1~16.04.york0 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.6) 20160609
configuration: --prefix=/usr --extra-version='1~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
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
-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 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
- 最上面部分是ffmpeg的版本信息和各模块的版本信息。
1.1 ffmpeg命令的语法结构
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
- 语法结构很简单。
- 中括号中的参数是可选项。
- options是对输入和输出都有影响的选项。
-
[[infile options] -i infile]...指定输入选项和输入文件，...表示可以包含多个输入。 -
{[outfile options] outfile}...指定输出选项和输出文件，...表示可以包含多个输出。
1.2 获取详细的help信息
ffmpeg -help给出了基本的帮助信息，其中下面的信息说明了如何获得更全面的帮助信息。
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.
-
-h long: 打印更多的选项参数。 -
-h full: 打印所有的选项参数，包括所有针对于format和codec的选项，信息特别的长。 -
-h type=name: 打印打印指定名称的decoder/encoder/demuxer/muxer/filter的所有选项信息。 -
man ffmpeg: 查看ffmpeg的帮助手册。
特别强调一下-h type=name这个命令，要经常去使用这个命令。比如查看libx264支持的参数，执行ffmpeg -h encoder=libx264，会打印libx264 encoder的使用说明：
Encoder libx264 [libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10]:
General capabilities: delay threads
Threading capabilities: auto
Supported pixel formats: yuv420p yuvj420p yuv422p yuvj422p yuv444p yuvj444p nv12 nv16 nv21
libx264 AVOptions:
-preset <string> E..V.... Set the encoding preset (cf. x264 --fullhelp) (default "medium")
-tune <string> E..V.... Tune the encoding params (cf. x264 --fullhelp)
-profile <string> E..V.... Set profile restrictions (cf. x264 --fullhelp)
-fastfirstpass <boolean> E..V.... Use fast settings when encoding first pass (default true)
-level <string> E..V.... Specify level (as defined by Annex A)
-passlogfile <string> E..V.... Filename for 2 pass stats
-wpredp <string> E..V.... Weighted prediction for P-frames
-a53cc <boolean> E..V.... Use A53 Closed Captions (if available) (default true)
-x264opts <string> E..V.... x264 options
-crf <float> E..V.... Select the quality for constant quality mode (from -1 to FLT_MAX) (default -1)
-crf_max <float> E..V.... In CRF mode, prevents VBV from lowering quality beyond this point. (from -1 to FLT_MAX) (default -1)
-qp <int> E..V.... Constant quantization parameter rate control method (from -1 to INT_MAX) (default -1)
-aq-mode <int> E..V.... AQ method (from -1 to INT_MAX) (default -1)
none E..V....
variance E..V.... Variance AQ (complexity mask)
autovariance E..V.... Auto-variance AQ
autovariance-biased E..V.... Auto-variance AQ with bias to dark scenes
-aq-strength <float> E..V.... AQ strength. Reduces blocking and blurring in flat and textured areas. (from -1 to FLT_MAX) (default -1)
-psy <boolean> E..V.... Use psychovisual optimizations. (default auto)
-psy-rd <string> E..V.... Strength of psychovisual optimization, in <psy-rd>:<psy-trellis> format.
-rc-lookahead <int> E..V.... Number of frames to look ahead for frametype and ratecontrol (from -1 to INT_MAX) (default -1)
-weightb <boolean> E..V.... Weighted prediction for B-frames. (default auto)
-weightp <int> E..V.... Weighted prediction analysis method. (from -1 to INT_MAX) (default -1)
none E..V....
simple E..V....
smart E..V....
-ssim <boolean> E..V.... Calculate and print SSIM stats. (default auto)
-intra-refresh <boolean> E..V.... Use Periodic Intra Refresh instead of IDR frames. (default auto)
-bluray-compat <boolean> E..V.... Bluray compatibility workarounds. (default auto)
-b-bias <int> E..V.... Influences how often B-frames are used (from INT_MIN to INT_MAX) (default INT_MIN)
-b-pyramid <int> E..V.... Keep some B-frames as references. (from -1 to INT_MAX) (default -1)
none E..V....
strict E..V.... Strictly hierarchical pyramid
normal E..V.... Non-strict (not Blu-ray compatible)
-mixed-refs <boolean> E..V.... One reference per partition, as opposed to one reference per macroblock (default auto)
-8x8dct <boolean> E..V.... High profile 8x8 transform. (default auto)
-fast-pskip <boolean> E..V.... (default auto)
-aud <boolean> E..V.... Use access unit delimiters. (default auto)
-mbtree <boolean> E..V.... Use macroblock tree ratecontrol. (default auto)
-deblock <string> E..V.... Loop filter parameters, in <alpha:beta> form.
-cplxblur <float> E..V.... Reduce fluctuations in QP (before curve compression) (from -1 to FLT_MAX) (default -1)
-partitions <string> E..V.... A comma-separated list of partitions to consider. Possible values: p8x8, p4x4, b8x8, i8x8, i4x4, none, all
-direct-pred <int> E..V.... Direct MV prediction mode (from -1 to INT_MAX) (default -1)
none E..V....
spatial E..V....
temporal E..V....
auto E..V....
-slice-max-size <int> E..V.... Limit the size of each slice in bytes (from -1 to INT_MAX) (default -1)
-stats <string> E..V.... Filename for 2 pass stats
-nal-hrd <int> E..V.... Signal HRD information (requires vbv-bufsize; cbr not allowed in .mp4) (from -1 to INT_MAX) (default -1)
none E..V....
vbr E..V....
cbr E..V....
-avcintra-class <int> E..V.... AVC-Intra class 50/100/200 (from -1 to 200) (default -1)
-motion-est <int> E..V.... Set motion estimation method (from -1 to 4) (default -1)
dia E..V....
hex E..V....
umh E..V....
esa E..V....
tesa E..V....
-forced-idr <boolean> E..V.... If forcing keyframes, force them as IDR frames. (default false)
-coder <int> E..V.... Coder type (from -1 to 1) (default default)
default E..V....
cavlc E..V....
cabac E..V....
vlc E..V....
ac E..V....
-b_strategy <int> E..V.... Strategy to choose between I/P/B-frames (from -1 to 2) (default -1)
-chromaoffset <int> E..V.... QP difference between chroma and luma (from INT_MIN to INT_MAX) (default -1)
-sc_threshold <int> E..V.... Scene change threshold (from INT_MIN to INT_MAX) (default -1)
-noise_reduction <int> E..V.... Noise reduction (from INT_MIN to INT_MAX) (default -1)
-x264-params <string> E..V.... Override the x264 configuration using a :-separated list of key=value parameters
1.3 打印帮助或支持能力的信息
ffmpeg -help打印的下面部分的信息说明了如何获取一些help信息和各种格式支持的能力。
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
1.4 全局选项
帮助信息的下面部分是全局选项的说明。
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 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)
- 很多选项都经常使用，比如
-v,-y。
1.5 文件选项
帮助信息的下面部分是针对每个文件可以指定的选项。
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
- 比如
-f fmt指定文件的格式。 -
-c,-t,-to,-ss这几个选项都比较常用。
1.6 视频/音频/字幕相关的选项
帮助信息的下面部分是针对视频/音频/字幕相关的选项。
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
- 上面列出的选项大多数都是经常会用到的。
2. 流选择选项
一些媒体格式如Mp4、AVI等可以包含多种类型的流。
FFmpeg可以识别5种流类型： 音频audio (a), 附件attachment (t), 数据data (d), 字幕subtitle (s) 和 视频video (v)。
可以通过-map选项来选择需要的流，语法格式如下：
file_number:stream_type[:stream_number]
file_number和stream_number分别表示文件索引和流索引。
有一些特别的流选择指令：
-map 0 ：选择所有的流类型和其中所有的流。
-map i:v ：选择文件i中的所有视频流； -map i:a 选择所有的音频流；-map i:s
选择所有的字幕流。
3. 视频封装解封装
3.1 视频格式转换
ffmpeg -i input.avi c:a copy c:v copy output.mp4
ffmpeg -i input.mp4 output.ts
3.2 分离/合并视频音频流
ffmpeg -i input-video -vn -c:a copy output-audio //分离音频流
//-vn is no video.
//-acodec copy says use the same audio stream that's already in there.
ffmpeg -i input-video -c:v copy -an output-video //分离视频流
//-an is no audio.
//-vcodec copy says use the same video stream that's already in there.
ffmpeg -i input-video -c:v copy -an output-video -c:a -vn output-audio //同时分离音频和视频流
ffmpeg -i video_file -i audio_file -c:v copy -c:a copy output_file //合并视频音频流
3.3 截取视频片段
ffmpeg -ss 5 -i input.mp4 -t 10 -c:v copy -c:a copy output.mp4
//-ss 5指定从输入视频第5秒开始截取，-t 10指明最多截取10秒。
//而-c:v copy -c:a copy标示视频与音频的编码不发生改变，而是直接复制，这样会大大提升速度，因为这样就不需要完全解码视频。
截取10s到20s
ffmpeg -i test.mp4 -c:v libx264 -filter:v select="between(t\, 10\, 20)" out.mp4
从头截取前10帧
ffmpeg -i test.mp4 -c:v libx264 -filter:v select="gt(n\, -1)" -vframes 10 out.mp4
ffmpeg -i test.mp4 -c:v libx264 -filter:v select="between(n\, 0\, 9)" out.mp4
中间截取 (10-20帧)
ffmpeg -i test.mp4 -c:v libx264 -filter:v select="between(n\, 10\, 20)" out.mp4
截取第10帧
ffmpeg -i test.mp4 -vf "select=eq(n\, 9)" -vframes -y 1 out.png
3.4 视频转换为m3u8格式
ffmpeg -i yoona.mp4 -c copy -map 0 -f segment -segment_list yoona.m3u8 -segment_time 10 yoona-%04d.ts
- Set segment duration to time, the value must be a duration specification. Default value is "2".
- Note that splitting may not be accurate, unless you force the reference stream key-frames at the given time. See the introductory notice and the examples below.
3.5 把视频文件推送到rtmp服务器
ffmpeg -re -i jack.mp4 -c copy -f flv rtmp://host/live/test
3.6 对视频进行切片
均匀切片
ffmpeg -i input.mp4 -c copy -f segment -segment_format mp4 -segment_time 300 -reset_timestamps 1 test_output-%d.mp4
- 以上命令把input.mp4切分为5分钟时长的视频片段。
- segment muxer的参数可以使用
ffmpeg -h muxer=segment查看
按照时间点进行剪切
ffmpeg -i input.mp4 -c copy -f segment -segment_format mp4 -segment_times 60,120,150 -reset_timestamps 1 test_output-%d.mp4
- 在第60秒、第120秒和第150秒这三个时间点进行切片。
4. 视频解码编码
4.1 视频截图
获取视频时间点01:23:45的截图
ffmpeg -ss 01:23:45 -i input -vframes 1 -q:v 2 output.jpg
-i input file the path to the input file
-ss 01:23:45 seek the position to the specified timestamp
-vframes 1 only handle one video frame
-q:v 2 to control output quality. Full range is a linear scale of 1-31 where a lower value results in a higher quality. 2-5 is a good range to try.
output.jpg output filename, should have a well-known extension
截取视频帧序号34的图像，帧序号从0开始。
ffmpeg -i <input> -vf "select=eq(n\,34)" -vframes 1 out.png
4.2 视频/图片尺寸修改
ffmpeg -i sample.jpg -s w*h out.jpg
4.3 分离视频的YUV通道分量
ffmpeg -i jack.mp4 -filter_complex "extractplanes=y+u+v[y][u][v]" -map "[y]" jack_y.mp4 -map "[u]" jack_u.mp4 -map "[v]" jack_v.mp4
4.4 图片序列与视频的互相转换
ffmpeg -i %04d.jpg output.mp4
ffmpeg -i input.mp4 %04d.jpg
\\第一行命令是把0001.jpg、0002.jpg、0003.jpg等编码成output.mp4，
\\第二行则是相反把input.mp4变成0001.jpg……。
\\%04d.jpg表示从1开始用0补全的4位整数为文件名的jpg文件序列。
4.5 yuv压缩为264 MP4文件
ffmpeg -s 1280x720 -r 25 -f rawvideo -pix_fmt yuv420p -i test_1280x720_25.yuv -c:v libx264 -y test.mp4
5. 视频filter
5.1 视频加水印
ffmpeg -i xizong.mp4 -i fleight.jpg -filter_complex "overlay=W-w-5:5" -codec:a copy xizong_fleight.mp4
//在右上角加水印，边距为5像素。
5.2 视频旋转transpose
顺时针翻转90度
ffmpeg -i input -vf transpose=1 output
翻转180度
ffmpeg -i in.mp4 -vf "transpose=1,transpose=1" out.mp4
5.3 调色3DLutFilter
应用颜色查找表Lut，有‘nearest’、‘trilinear’、‘tetrahedral’三种插值算法，命令行调用如下：
ffmpeg -i log.mp4 -vf lut3d="file=DK79.cube" out.mp4
5.4 图像/视频转换成黑白的
图像转换成黑白的
ffmpeg -i sample.png -vf hue=s=0 output.png
//把视频转换为黑白的
ffmpeg -i julin_5s.mp4 -vf hue=s=0 -c:a copy julin_monochrome.mp4
5.5 裁剪视频crop
使用-crop选项，语法如下：
crop=ow[:oh[:x[:y[:keep_aspect]]]]
ow、oh表示裁减之后输出视频的宽和高，
x、y表示在输入视频上开始裁减的横坐标和纵坐标，
keep_aspect: 1表示保持裁剪后输出的纵横比与输入一致，0表示不保持。
裁剪输入视频的左三分之一，中间三分之一，右三分之一:
ffmpeg -i input -vf crop=iw/3:ih :0:0 output
ffmpeg -i input -vf crop=iw/3:ih :iw/3:0 output
ffmpeg -i input -vf crop=iw/3:ih :iw/3*2:0 output
裁剪中间一半区域：
ffmpeg -i input -vf crop=iw/2:ih/2 output
5.6 视频尺寸缩放scale
将输入的1920x1080缩小到960x540输出
ffmpeg -i input.mp4 -vf scale=960:540 output.mp4
//ps: 如果540不写，写成-1，即scale=960:-1, 那也是可以的，ffmpeg会通知缩放滤镜在输出时保持原始的宽高比。
5.7 视频中去水印delogo
使用delogo filter
它对logo周围像素的简单插值来实现。只需设置一个覆盖logo的矩形。在每个方向上，紧靠矩形外的下一个像素的值将用于计算矩形内的插值像素值。
语法：-vf delogo=x:y:w:h[:t[:show]]
x:y 离左上角的坐标
w:h logo的宽和高
show：默认值0，若设置为1，指定区域的边界会绘制一个绿色的矩形框用于找到合适的x、y、w、h参数。
示例
ffmpeg -i input.mp4 -vf delogo=x=0:y=0:w=100:h=60 output.mp4
5.8 给视频或图像加上黑边pad
比如一个输入视频尺寸是1280x534的源，想要加上黑边变成1280x720，使用下面的命令可以实现。
ffmpeg -i input.mp4 -vf pad=1280:720:0:93:black output.mp4
- 按照从左到右的顺序依次为：“宽”、“高”、“X坐标”和“Y坐标”，宽和高指的是输入视频尺寸（包含加黑边的尺寸），X、Y指的是视频所在位置。
- 默认是加黑色的边，black可以不写。
- 上面的命令中93是根据
(720-534) / 2计算得到。
如果视频原始1920x800的话，完整的语法应该是：
-vf 'scale=1280:534,pad=1280:720:0:93:black'
- 先将视频缩小到1280x534，然后在加入黑边变成1280x720，将1280x534的视频放置在x=0，y=93的地方。
5.9 计算psnr/ssim
分析 psnr 主要是针对转码前的视频和转码后的视频的对比；如果转码是降分辨率，对比的时候，还需要对源视频加 -s widthxhigh;保证分辨率一致再做 psnr 和 ssim 的计算；
psnr
ffmpeg -i src.mp4 -i dst.mp4 -lavfi psnr="stats_file=psnr.log" -f null -
ssim
ffmpeg -i src.mp4 -i dst.mp4 -lavfi ssim="stats_file=ssim.log" -f null -
同时计算psnr和ssim
ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
5.10 视频按时间拼接
使用 FFmpeg 的concat 工具。
先创建一个文本文件，包含需要拼接的文件的列表。
filelist.txt：
file 'input1.mp4'
file 'input2.mp4'
file 'input3.mp4'
命令
ffmpeg -f concat -i filelist.txt -c copy output.mp4
5.11 视频左右拼接
ffmpeg -ss 00:05:00 -i v1.mp4 -ss -ss 00:05:00 -i v2.mp4 -filter_complex "[0:v]crop=iw/2:ih:0:0[v1];[1:v]crop=iw/2:ih:iw/2:0[v2];[v1][v2]hstack[v3];[v3]drawbox=iw/2-1:0:2:ih[v4]" -map [v4] -map 0:a -c:a copy -c:v libx264 -t 00:01:00 -y out.mp4
5.12 打印视频帧的一些信息showinfo
ffmpeg -hide_banner -i v.mp4 -vf showinfo -frames:v 1 -f null /dev/null
打印的信息类似
[Parsed_showinfo_0 @ 0x74f2d40] config out time_base: 0/0, frame_rate: 0/0
[Parsed_showinfo_0 @ 0x74f2d40] n: 0 pts: 0 pts_time:0 pos: 55743 fmt:yuv420p sar:1395/1394 s:656x360 i:P iskey:1 type:I checksum:81726064 plane_checksum:[C119CB7C 5DDE813C 3A76139D] mean:[106 126 142] stdev:[52.5 8.3 18.8]
[Parsed_showinfo_0 @ 0x74f2d40] side data - User Data Unregistered:
[Parsed_showinfo_0 @ 0x74f2d40] UUID=dc45e9bd-e6d9-48b7-962c-d820d923eeef
[Parsed_showinfo_0 @ 0x74f2d40] color_range:unknown color_space:unknown color_primaries:unknown color_trc:unknown
[Parsed_showinfo_0 @ 0x74f2d40] n: 1 pts: 1024 pts_time:0.0666667 pos: 69559 fmt:yuv420p sar:1395/1394 s:656x360 i:P iskey:0 type:B checksum:3AB39554 plane_checksum:[C775F70F 3E19845B DFD819DB] mean:[107 126 142] stdev:[52.5 8.3 18.8]
[Parsed_showinfo_0 @ 0x74f2d40] color_range:unknown color_space:unknown color_primaries:unknown color_trc:unknown
5.13 生成纯色的图片
生成黑色的图片
ffmpeg -f lavfi -i color=Black:640x480 -frames:v 1 -y black.jpg
- 详细参数介绍见ffmpeg文档
5.14 打印帧序号/pts到视频帧水印drawtext
打印帧序号
ffmpeg -i test.mp4 -vf drawtext=fontcolor=red:fontsize=40:fontfile=msyh.ttf:line_spacing=7:text=%{n}:x=50:y=50 -vsync 0 -y out.mp4
打印帧pts
ffmpeg -i test.mp4 -vf drawtext=fontcolor=red:fontsize=30:fontfile=msyh.ttf:line_spacing=7:text=%{pts}:x=50:y=50 -vsync 0 -y out.mp4
打印帧类型
ffmpeg -i test.mp4 -vf drawtext=fontcolor=red:fontsize=20:fontfile=msyh.ttf:line_spacing=7:text=%{pict_type}:x=50:y=50 -vsync 0 -y out.mp4
把视频的pts[时间戳]添加为视频水印，精度到毫秒
ffmpeg -i test.mp4 -vf "drawtext=fontsize=60:text='%{pts\:hms}'" -c:v libx264 -c copy -f mp4 output.mp4 -y
6. 音频解码编码
6.1 PCM原始数据和WAV格式转换
wav格式转换为PCM裸流
ffmpeg -i xizong.wav -f f32le -ar 44100 -acodec pcm_f32le output_f32le.raw
参数说明：
-f f32le … 浮点数32为小字端的采样格式
-ar 44100 … 采样频率
-ac 2 … 声道数量
PCM裸流转wav格式
ffmpeg -f f32le -ar 44100 -ac 2 -acodec pcm_f32le -i xizong_f32le.raw xizong_f32le.wav
说明需要先使用ffprobe查看wav中音频的采样格式，以上例子是使用的f32le采样格式的数据。
7. 音频filter
7.1 倍速atempo
速度减半
ffmpeg -i input.mp3 -af atempo=0.5 output.mp3
2倍速率
ffmpeg -i input.mp3 -af atempo=2 output.mp3
8. 字幕相关
8.1 字幕文件转换
字幕文件有很多种，常见的有 .srt , .ass 文件等。
//将.srt文件转换成.ass文件
ffmpeg -i subtitle.srt subtitle.ass
将.ass文件转换成.srt文件
ffmpeg -i subtitle.ass subtitle.srt
8.2 集成字幕到视频文件
ffmpeg -i input.mp4 -i subtitles.srt -c:s mov_text -c:v copy -c:a copy output.mp4
9. ffplay命令
9.1 ffplay播放yuv视频数据
ffplay -f <文件格式> -pix_fmt <像素格式> -video_size <视频尺寸> <文件名>
示例：
ffplay -f rawvideo -pix_fmt yuv420p -framerate 30 -video_size 848x480 yuv_video
9.2 ffplay播放PCM音频数据
ffplay -f <格式名> -ac <声道数> -ar <采样率> <文件名>
示例：
ffplay -f f32le -ac 1 -ar 48000 pcm_audio
9.3 ffplay播放音频并显示波形图
ffplay -showmode 1 simple.mp4
9.4 ffplay指定显示的宽高
ffplay -x 1208 -y 720 sample.mp4
ffplay -y 720 sample.mp4
- 播放窗口高为720，宽会等比缩放
9.5 ffplay播放中的常用按键
- 空格键或者p：暂停或者继续
- s：跳转到下一帧
- m: 静音或者取消静音
- 向左或向右方向键：向后或者向前seek 10s
- 点击鼠标右键：seek到对应窗口宽度百分比的进度
- 鼠标左键双击：切换全屏/非全屏
9.6 ffplay播放加载字幕
ffplay -vf subtitles=video.srt test.mp4
9.7 ffplay显示视频编码的运动向量（mv）信息
ffplay -flags2 +export_mvs -vf codecview=mv=pf+bf+bb test.mp4
10. ffprobe命令
10.1 ffprobe查看媒体文件的信息
ffprobe target.mp4 -show_format -show_streams -print_format json -loglevel fatal
示例输出：
root@smallest:/home/video# ffprobe jack.mp4 -show_format -show_streams -print_format json -loglevel fatal
{
"streams": [
{
"index": 0,
"codec_name": "h264",
"codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
"profile": "High",
"codec_type": "video",
"codec_time_base": "1/50",
"codec_tag_string": "avc1",
"codec_tag": "0x31637661",
"width": 848,
"height": 480,
"coded_width": 848,
"coded_height": 480,
"has_b_frames": 1,
"sample_aspect_ratio": "1:1",
"display_aspect_ratio": "53:30",
"pix_fmt": "yuv420p",
"level": 30,
"chroma_location": "left",
"refs": 1,
"is_avc": "true",
"nal_length_size": "4",
"r_frame_rate": "25/1",
"avg_frame_rate": "25/1",
"time_base": "1/25000",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 39754000,
"duration": "1590.160000",
"bit_rate": "449785",
"bits_per_raw_sample": "8",
"nb_frames": "7499",
"disposition": {
"default": 1,
"dub": 0,
"original": 0,
"comment": 0,
"lyrics": 0,
"karaoke": 0,
"forced": 0,
"hearing_impaired": 0,
"visual_impaired": 0,
"clean_effects": 0,
"attached_pic": 0,
"timed_thumbnails": 0
},
"tags": {
"creation_time": "2016-09-14T08:14:35.000000Z",
"language": "und",
"handler_name": "TrackHandler"
}
},
{
"index": 1,
"codec_name": "aac",
"codec_long_name": "AAC (Advanced Audio Coding)",
"profile": "HE-AAC",
"codec_type": "audio",
"codec_time_base": "1/48000",
"codec_tag_string": "mp4a",
"codec_tag": "0x6134706d",
"sample_fmt": "fltp",
"sample_rate": "48000",
"channels": 2,
"channel_layout": "stereo",
"bits_per_sample": 0,
"r_frame_rate": "0/0",
"avg_frame_rate": "0/0",
"time_base": "1/24000",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 7199744,
"duration": "299.989333",
"bit_rate": "48030",
"max_bit_rate": "56888",
"nb_frames": "7031",
"disposition": {
"default": 1,
"dub": 0,
"original": 0,
"comment": 0,
"lyrics": 0,
"karaoke": 0,
"forced": 0,
"hearing_impaired": 0,
"visual_impaired": 0,
"clean_effects": 0,
"attached_pic": 0,
"timed_thumbnails": 0
},
"tags": {
"creation_time": "2016-09-14T08:11:52.000000Z",
"language": "und",
"handler_name": "Sound Media Handler"
}
}
],
"format": {
"filename": "jack.mp4",
"nb_streams": 2,
"nb_programs": 0,
"format_name": "mov,mp4,m4a,3gp,3g2,mj2",
"format_long_name": "QuickTime / MOV",
"start_time": "0.000000",
"duration": "299.988333",
"size": "18813764",
"bit_rate": "501719",
"probe_score": 100,
"tags": {
"major_brand": "mp42",
"minor_version": "0",
"compatible_brands": "isomavc1mp42",
"creation_time": "2016-09-14T08:14:35.000000Z"
}
}
}
-
-print_format json: 结果以json格式呈现 -
-show_format: 打印封装格式信息，在format节点中。 -
-show_streams: 打印流信息，在streams节点中。
10.2 ffprobe查看时间戳
查看视频dts
ffprobe -show_packets -select_streams v 1.ts | grep dts_time
查看视频pts
ffprobe -show_packets -select_streams v 1.ts | grep pts_time
查看视频流前几帧的pts
ffprobe -v error -of compact -read_intervals %+#10 -show_packets -select_streams v 1.ts
查看关键帧的pts
ffprobe -v error -select_streams v:0 -show_entries packet=pts_time,flags -of csv=print_section=0 input.mp4 | awk -F',' '/K/ {print $1}'
查看关键帧帧间的间隔
./ffprobe -of compact -select_streams v -show_packets 'test.mp4'| grep K_ | awk 'BEGIN{FS="|";last=-1}{split($5,a,"="); if(last != -1) {print "Keframe pos: " a[2] ", Interval: " a[2]-last " seconds"} else {print "Keyframe: " a[2]}; last=a[2]}'
10.3 ffprobe查看每帧的帧类型信息
ffprobe -select_streams v:0 -show_frames -of xml test.mp4
- 该命令的目的是以 XML 格式输出视频文件中第一个视频流的每一帧的详细信息。这些信息可以包括关键帧标识、时间戳、帧的宽度和高度等。
11. 其他
11.1 ffmpeg或ffplay 打开 DEBUG 日志输出。
$ ffplay -v debug $URL
API中开启debug日志
av_log_set_level(AV_LOG_DEBUG);
11.2 FFmpeg命令日志输出到文件
执行ffmpeg或者ffprobe输出重定向到文件的时候发现文件是空的。
可以采用下面的方式。
ffprobe xxx > file 2>&1
- shell输出分好多种，0表示键盘输出，1表示屏幕输出，2表示错误输出。 cmd > file，只是把屏幕输出重定向到文件中。
- 调用ffmpeg相关命令，打印信息都被终端认为是错误输出，但是一般情况下这种信息也会输出到屏幕上,所以我们可以在屏幕上看到它。但是，当我们想重定向到文件中，却被系统认为是错误输出而忽略。
-
2>&1表示错误输出重定向到屏幕输出。&标明其后面跟的是一个文件描述符，而不是一个文件名。
11.3 打印支持DirectShow的设备列表
打印支持DirectShow的设备列表
ffmpeg -list_devices true -f dshow -i dummy
打开名称为“Lenovo EasyCamera”的摄像头
ffmpeg -f dshow -i video="Lenovo EasyCamera"
