基本选项: -formats 输出所有可用格式
-f fmt 指定格式(音频或视频格式)
-i filename 指定输入文件名，在linux下当然也能指定:0.0(屏幕录制)或摄像头
-y 覆盖已有文件
-t duration 记录时长为t
-fs limit_size 设置文件大小上限
-ss time_off 从指定的时间(s)开始， [-]hh:mm:ss[.xxx]的格式也支持
-itsoffset time_off 设置时间偏移(s)，该选项影响所有后面的输入文件。该偏移被加到输入文件的时戳，定义一个正偏移意味着相应的流被延迟了 offset秒。 [-]hh:mm:ss[.xxx]的格式也支持
-title string 标题
-timestamp time 时间戳
-author string 作者
-copyright string 版权信息
-comment string 评论
-album string album名
-v verbose 与log相关的
-target type 设置目标文件类型("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd", "ntsc-svcd", ...)
-dframes number 设置要记录的帧数
视频选项: -b 指定比特率(bits/s)，似乎ffmpeg是自动VBR的，指定了就大概是平均比特率
-bitexact 使用标准比特率
-vb 指定视频比特率(bits/s)
-vframes number 设置转换多少桢(frame)的视频
-r rate 帧速率(fps) （可以改，确认非标准桢率会导致音画不同步，所以只能设定为15或者29.97）
-s size 指定分辨率 (320x240)
-aspect aspect 设置视频长宽比(4:3, 16:9 or 1.3333, 1.7777)
-croptop size 设置顶部切除尺寸(in pixels)
-cropbottom size 设置底部切除尺寸(in pixels)
-cropleft size 设置左切除尺寸 (in pixels)
-cropright size 设置右切除尺寸 (in pixels)
-padtop size 设置顶部补齐尺寸(in pixels)
-padbottom size 底补齐(in pixels)
-padleft size 左补齐(in pixels)
-padright size 右补齐(in pixels)
-padcolor color 补齐带颜色(000000-FFFFFF)
-vn 取消视频
-vcodec codec 强制使用codec编解码方式('copy' to copy stream)
-sameq 使用同样视频质量作为源（VBR）
-pass n 选择处理遍数（1或者2）。两遍编码非常有用。第一遍生成统计信息，第二遍生成精确的请求的码率
-passlogfile file 选择两遍的纪录文件名为file
-newvideo 在现在的视频流后面加入新的视频流
高级视频选项 ：-pix_fmt format set pixel format, 'list' as argument shows all the pixel formats supported
-intra 仅适用帧内编码
-qscale q 以<数值>质量为基础的VBR，取值0.01-255，约小质量越好
-loop_input 设置输入流的循环数(目前只对图像有效)
-loop_output 设置输出视频的循环数，比如输出gif时设为0表示无限循环
-g int 设置图像组大小
-cutoff int 设置截止频率
-qmin int 设定最小质量，与-qmax（设定最大质量）共用，比如-qmin 10 -qmax 31
-qmax int 设定最大质量
-qdiff int 量化标度间最大偏差 (VBR)
-bf int 使用frames B 帧，支持mpeg1,mpeg2,mpeg4
音频选项: -ab 设置比特率(单位：bit/s，也许老版是kb/s)前面-ac设为立体声时要以一半比特率来设置，比如192kbps的就设成96，转换 默认比特率都较小，要听到较高品质声音的话建议设到160kbps（80）以上。
-aframes number 设置转换多少桢(frame)的音频
-aq quality 设置音频质量 (指定编码)
-ar rate 设置音频采样率 (单位：Hz)，PSP只认24000
-ac channels 设置声道数，1就是单声道，2就是立体声，转换单声道的TVrip可以用1（节省一半容量），高品质的DVDrip就可以用2
-an 取消音频
-acodec codec 指定音频编码('copy' to copy stream)
-vol volume 设置录制音量大小(默认为256) <百分比> ，某些DVDrip的AC3轨音量极小，转换时可以用这个提高音量，比如200就是原来的2倍
-newaudio 在现在的音频流后面加入新的音频流
字幕选项: -sn 取消字幕
-scodec codec 设置字幕编码('copy' to copy stream)
-newsubtitle 在当前字幕后新增
-slang code 设置字幕所用的ISO 639编码(3个字母)
Audio/Video 抓取选项:
-vc channel 设置视频捕获通道(只对DV1394)
-tvstd standard 设置电视标准 NTSC PAL(SECAM)
要得到一个高画质音质低容量的MP4的话，首先画面最好不要用固定比特率，而用VBR参数让程序自己去判断，而音质参数可以在原来的基础上提升一点，听起来要舒服很多，也不会太大（看情况调整 ）
转换为flv:
ffmpeg -i test.mp3 -ab 56 -ar 22050 -b 500 -r 15 -s 320x240 test.flv
ffmpeg -i test.wmv -ab 56 -ar 22050 -b 500 -r 15 -s 320x240 test.flv
转换文件格式的同时抓缩微图：
ffmpeg -i "test.avi" -y -f image2 -ss 8 -t 0.001 -s 350x240 'test.jpg'
对已有flv抓图：
ffmpeg -i "test.flv" -y -f image2 -ss 8 -t 0.001 -s 350x240 'test.jpg'
转换为3gp:
ffmpeg -y -i test.mpeg -bitexact -vcodec h263 -b 128 -r 15 -s 176x144 -acodec aac -ac 2 -ar 22500 -ab 24 -f 3gp test.3gp
ffmpeg -y -i test.mpeg -ac 1 -acodec amr_nb -ar 8000 -s 176x144 -b 128 -r 15 test.3gp
例：ffmpeg -y -i "test.avi" -title "Test" -vcodec xvid -s 368x208 -r 29.97 - b 1500 -acodec aac -ac 2 -ar 24000 -ab 128 -vol 200 -f psp -muxvb 768 "test.***"
# 参数解释：
-y（覆盖输出文件，即如果1.***文件已经存在的话，不经提示就覆盖掉了）
-i "1.avi"（输入文件是和ffmpeg在同一目录下的1.avi文件，可以自己加路径，改名字）
-title "Test"（在PSP中显示的影片的标题）
-vcodec xvid（使用XVID编码压缩视频，不能改的）
-s 368x208（输出的分辨率为368x208，注意片源一定要是16:9的不然会变形） -r 29.97（帧数，一般就用这个吧）
-b 1500（视频数据流量，用-b xxxx的指令则使用固定码率，数字随便改，1500以上没效果；还可以用动态码率如：-qscale 4和-qscale 6，4的质量比6高）
-acodec aac（音频编码用AAC）
-ac 2（声道数1或2）
-ar 24000（声音的采样频率，好像PSP只能支持24000Hz）
-ab 128（音频数据流量，一般选择32、64、96、128）
-vol 200（200%的音量，自己改）
-f psp（输出psp专用格式）
-muxvb 768（好像是给PSP机器识别的码率，一般选择384、512和768，我改成1500，PSP就说文件损坏了）
"test.***"（输出文件名，也可以加路径改文件名）
用-ss指定开始时间，用hh:mm:ss[.ms]格式，或者换算成用秒计。
用-t指定长度，和-ss的格式一样，用hh:mm:ss[.ms]格式，或者换算成用秒计。
如果-ss放在-i之前，就会成为输入选项，会先跳转过去。如果-i放在输出文件前面，则会成为输出选项，ffmpeg会先解码到给定时间，再开始编码行为，这样做会比较慢，但更精确。
如果想用这个方法无损分割（用-codec copy），是不一定能切准的。
各种滤镜:
Filters:
A = Audio input/output
V = Video input/output
N = Dynamic number and/or type of input/output
| = Source or sink filter
aconvert A->A Convert the input audio to sample_fmt:channel_layout
.
afade A->A Fade in/out input audio.
aformat A->A Convert the input audio to one of the specified form
ats.
ainterleave N->A Temporally interleave audio inputs.
allpass A->A Apply a two-pole all-pass filter.
amerge N->A Merge two or more audio streams into a single multi-
channel stream.
amix N->A Audio mixing.
anull A->A Pass the source unchanged to the output.
apad A->A Pad audio with silence.
aperms A->A Set permissions for the output audio frame.
aphaser A->A Add a phasing effect to the audio.
aresample A->A Resample audio data.
aselect A->N Select audio frames to pass in output.
asendcmd A->A Send commands to filters.
asetnsamples A->A Set the number of samples for each output audio fram
es.
asetpts A->A Set PTS for the output audio frame.
asetrate A->A Change the sample rate without altering the data.
asettb A->A Set timebase for the audio output link.
ashowinfo A->A Show textual information for each audio frame.
asplit A->N Pass on the audio input to N audio outputs.
astats A->A Show time domain statistics about audio frames.
astreamsync AA->AA Copy two streams of audio data in a configurable ord
er.
atempo A->A Adjust audio tempo.
bandpass A->A Apply a two-pole Butterworth band-pass filter.
bandreject A->A Apply a two-pole Butterworth band-reject filter.
bass A->A Boost or cut lower frequencies.
biquad A->A Apply a biquad IIR filter with the given coefficient
s.
channelmap A->A Remap audio channels.
channelsplit A->N Split audio into per-channel streams.
earwax A->A Widen the stereo image.
ebur128 A->N EBU R128 scanner.
equalizer A->A Apply two-pole peaking equalization (EQ) filter.
highpass A->A Apply a high-pass filter with 3dB point frequency.
join N->A Join multiple audio streams into multi-channel outpu
t.
lowpass A->A Apply a low-pass filter with 3dB point frequency.
pan A->A Remix channels with coefficients (panning).
silencedetect A->A Detect silence.
treble A->A Boost or cut upper frequencies.
volume A->A Change input volume.
volumedetect A->A Detect audio volume.
aevalsrc |->A Generate an audio signal generated by an expression.
anullsrc |->A Null audio source, return empty audio frames.
sine |->A Generate sine wave audio signal.
anullsink A->| Do absolutely nothing with the input audio.
alphaextract V->V Extract an alpha channel as a grayscale image compon
ent.
alphamerge VV->V Copy the luma value of the second input into the alp
ha channel of the first input.
ass V->V Render ASS subtitles onto input video using the liba
ss library.
bbox V->V Compute bounding box for each frame.
blackdetect V->V Detect video intervals that are (almost) black.
blackframe V->V Detect frames that are (almost) black.
blend VV->V Blend two video frames into each other.
boxblur V->V Blur the input.
colorbalance V->V Adjust the color balance.
colorchannelmixer V->V Adjust colors by mixing color channels.
colormatrix V->V Convert color matrix.
copy V->V Copy the input video unchanged to the output.
crop V->V Crop the input video to width:height:x:y.
cropdetect V->V Auto-detect crop size.
curves V->V Adjust components curves.
decimate N->V Decimate frames (post field matching filter).
delogo V->V Remove logo from input video.
deshake V->V Stabilize shaky video.
drawbox V->V Draw a colored box on the input video.
drawtext V->V Draw text on top of video frames using libfreetype l
ibrary.
edgedetect V->V Detect and draw edge.
fade V->V Fade in/out input video.
field V->V Extract a field from the input video.
fieldmatch N->V Field matching for inverse telecine.
fieldorder V->V Set the field order.
format V->V Convert the input video to one of the specified pixel formats.
fps V->V Force constant framerate.
framestep V->V Select one frame every N frames.
frei0r V->V Apply a frei0r effect.
geq V->V Apply generic equation to each pixel.
gradfun V->V Debands video quickly using gradients.
hflip V->V Horizontally flip the input video.
histeq V->V Apply global color histogram equalization.
histogram V->V Compute and draw a histogram.
hqdn3d V->V Apply a High Quality 3D Denoiser.
hue V->V Adjust the hue and saturation of the input video.
idet V->V Interlace detect Filter.
il V->V Deinterleave or interleave fields.
interlace V->V Convert progressive video into interlaced.
interleave N->V Temporally interleave video inputs.
kerndeint V->V Apply kernel deinterlacing to the input.
lut V->V Compute and apply a lookup table to the RGB/YUV inpu
t video.
lutrgb V->V Compute and apply a lookup table to the RGB input vi
deo.
lutyuv V->V Compute and apply a lookup table to the YUV input vi
deo.
mp V->V Apply a libmpcodecs filter to the input video.
mpdecimate V->V Remove near-duplicate frames.
negate V->V Negate input video.
noformat V->V Force libavfilter not to use any of the specified pi
xel formats for the input to the next filter.
noise V->V Add noise.
null V->V Pass the source unchanged to the output.
overlay VV->V Overlay a video source on top of the input.
pad V->V Pad input image to width:height[:x:y[:color]] (defau
lt x and y: 0, default color: black).
perms V->V Set permissions for the output video frame.
pixdesctest V->V Test pixel format definitions.
pp V->V Filter video using libpostproc.
removelogo V->V Remove a TV logo based on a mask image.
scale V->V Scale the input video to width:height size and/or co
nvert the image format.select V->N Select video frames to pass in output.
sendcmd V->V Send commands to filters.
separatefields V->V Split input video frames into fields.
setdar V->V Set the frame display aspect ratio.
setfield V->V Force field for the output video frame.
setpts V->V Set PTS for the output video frame.
setsar V->V Set the pixel sample aspect ratio.
settb V->V Set timebase for the video output link.
showinfo V->V Show textual information for each video frame.
smartblur V->V Blur the input video without impacting the outlines.
split V->N Pass on the input video to N outputs.
stereo3d V->V Convert video stereoscopic 3D view.
subtitles V->V Render text subtitles onto input video using the lib
ass library.
super2xsai V->V Scale the input by 2x using the Super2xSaI pixel art
algorithm.
swapuv V->V Swap U and V components.
telecine V->V Apply a telecine pattern.
thumbnail V->V Select the most representative frame in a given sequ
ence of consecutive frames.
tile V->V Tile several successive frames together.
tinterlace V->V Perform temporal field interlacing.
transpose V->V Transpose input video.
unsharp V->V Sharpen or blur the input video.
vflip V->V Flip the input video vertically.
yadif V->V Deinterlace the input image.
cellauto |->V Create pattern generated by an elementary cellular a
utomaton.
color |->V Provide an uniformly colored input.
frei0r_src |->V Generate a frei0r source.
life |->V Create life.
mandelbrot |->V Render a Mandelbrot fractal.
mptestsrc |->V Generate various test pattern.
nullsrc |->V Null video source, return unprocessed video frames.
rgbtestsrc |->V Generate RGB test pattern.
smptebars |->V Generate SMPTE color bars.
smptehdbars |->V Generate SMPTE HD color bars.
testsrc |->V Generate test pattern.
nullsink V->| Do absolutely nothing with the input video.
concat N->N Concatenate audio and video streams.
showspectrum A->V Convert input audio to a spectrum video output.
showwaves A->V Convert input audio to a video output.
amovie |->N Read audio from a movie source.
movie |->N Read from a movie source.
ffbuffersink V->| Buffer video frames, and make them available to the
end of the filter graph.
ffabuffersink A->| Buffer audio frames, and make them available to the
end of the filter graph.
abuffer |->A Buffer audio frames, and make them accessible to the
filterchain.
buffer |->V Buffer video frames, and make them accessible to the
filterchain.
abuffersink A->| Buffer audio frames, and make them available to the
end of the filter graph.
buffersink V->| Buffer video frames, and make them available to the
end of the filter graph.
afifo A->A Buffer input frames and send them when they are requ
ested.
fifo V->V Buffer input images and send them when they are requ
ested.
