进入bin目录,输入ffmpeg -help可以查看相关命令参数,如下:
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:显示许可证,执照,版本信息-L show license -h topic show help -? topic show help-help topic show help--help topic show help-version show version显示配置命令参数-buildconf show build configuration显示可用的格式(编码,协议相关的)-formats show available formats-devices show available devices显示支持的编解码格式-codecs show available codecs-decoders show available decoders-encoders show available encoders显示支持的bit流过滤协议-bsfs show available bit stream filters显示支持的协议-protocols show available protocols-filters show available filters显示支持的像素格式(rgb,yuv,nv...)-pix_fmts show available pixel formats显示standard声道布局-layouts show standard channel layouts显示音频采样的格式(8位,16,32位...)-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硬件加速方法-hwaccels show available HW acceleration methodsGlobal options (affect whole program instead of just one file:日志相关-loglevel loglevel set logging level-v loglevel set logging level-report generate a report设置缓冲区-max_alloc bytes set maximum size of a single allocated block覆盖输出文件-y overwrite output files-n never overwrite output files-ignore_unknown Ignore unknown stream types-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:强制采用格式fmt-f fmt force format 编解码名称-c codec codec name-codec codec codec name-pre preset preset name设置outfile metadata from infile-map_metadata outfile[,metadata]:infile[,metadata] set metadata information of outfile from infile设置纪录时间-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视频参数Video options:设置视频帧的数量-vframes number set the number of video frames to output设置帧率-r rate set frame rate (Hz value, fraction or abbreviation)设置帧的大小(格式为宽X高,如1080X720)-s size set frame size (WxH or abbreviation)设置横纵比-aspect aspect set aspect ratio (4:3, 16:9 or 1.3333, 1.7777)设置的文件比特数量-bits_per_raw_sample number set the number of bits per raw sample不做视频记录-vn disable video强制使用codec编解码方式-vcodec codec force video codec ('copy' to copy stream)-timecode hh:mm:ss[:;.]ff set initial TimeCode value.处理的遍数-pass n select the pass number (1 to 3)音视频码率-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音频参数Audio options:设置音频帧的数量-aframes number set the number of audio frames to output设置音频的质量-aq quality set audio quality (codec-specific)设置音频的采样率-ar rate set audio sampling rate (in Hz)设置音频的通道-ac channels set number of audio channels不做音频记录-an disable audio强制使用编码-acodec codec force audio codec ('copy' to copy stream)设置音频音量-vol volume change audio volume (256=normal)-af filter_graph set audio filtersSubtitle 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常用参数如下:
主要参数： -i 设定输入流 -f 设定输出格式 -ss 开始时间 视频参数： -b 设定视频流量，默认为200Kbit/s -r 设定帧速率，默认为25 -s 设定画面的宽与高 -aspect 设定画面的比例 -vn 不处理视频 -vcodec 设定视频编解码器，未设定时则使用与输入流相同的编解码器 音频参数： -ar 设定采样率 -ac 设定声音的Channel数 -acodec 设定声音编解码器，未设定时则使用与输入流相同的编解码器 -an 不处理音频新闻热点
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