| \input texinfo @c -*- texinfo -*- |
| |
| @settitle FFmpeg Documentation |
| @titlepage |
| @sp 7 |
| @center @titlefont{FFmpeg Documentation} |
| @sp 3 |
| @end titlepage |
| |
| |
| @chapter Introduction |
| |
| FFmpeg is a very fast video and audio converter. It can also grab from |
| a live audio/video source. |
| |
| The command line interface is designed to be intuitive, in the sense |
| that FFmpeg tries to figure out all parameters that can possibly be |
| derived automatically. You usually only have to specify the target |
| bitrate you want. |
| |
| FFmpeg can also convert from any sample rate to any other, and resize |
| video on the fly with a high quality polyphase filter. |
| |
| @chapter Quick Start |
| |
| @c man begin EXAMPLES |
| @section Video and Audio grabbing |
| |
| FFmpeg can grab video and audio from devices given that you specify the input |
| format and device. |
| |
| @example |
| ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg |
| @end example |
| |
| Note that you must activate the right video source and channel before |
| launching FFmpeg with any TV viewer such as xawtv |
| (@url{http://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also |
| have to set the audio recording levels correctly with a |
| standard mixer. |
| |
| @section X11 grabbing |
| |
| FFmpeg can grab the X11 display. |
| |
| @example |
| ffmpeg -f x11grab -s cif -i :0.0 /tmp/out.mpg |
| @end example |
| |
| 0.0 is display.screen number of your X11 server, same as |
| the DISPLAY environment variable. |
| |
| @example |
| ffmpeg -f x11grab -s cif -i :0.0+10,20 /tmp/out.mpg |
| @end example |
| |
| 0.0 is display.screen number of your X11 server, same as the DISPLAY environment |
| variable. 10 is the x-offset and 20 the y-offset for the grabbing. |
| |
| @section Video and Audio file format conversion |
| |
| * FFmpeg can use any supported file format and protocol as input: |
| |
| Examples: |
| |
| * You can use YUV files as input: |
| |
| @example |
| ffmpeg -i /tmp/test%d.Y /tmp/out.mpg |
| @end example |
| |
| It will use the files: |
| @example |
| /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V, |
| /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc... |
| @end example |
| |
| The Y files use twice the resolution of the U and V files. They are |
| raw files, without header. They can be generated by all decent video |
| decoders. You must specify the size of the image with the @option{-s} option |
| if FFmpeg cannot guess it. |
| |
| * You can input from a raw YUV420P file: |
| |
| @example |
| ffmpeg -i /tmp/test.yuv /tmp/out.avi |
| @end example |
| |
| test.yuv is a file containing raw YUV planar data. Each frame is composed |
| of the Y plane followed by the U and V planes at half vertical and |
| horizontal resolution. |
| |
| * You can output to a raw YUV420P file: |
| |
| @example |
| ffmpeg -i mydivx.avi hugefile.yuv |
| @end example |
| |
| * You can set several input files and output files: |
| |
| @example |
| ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg |
| @end example |
| |
| Converts the audio file a.wav and the raw YUV video file a.yuv |
| to MPEG file a.mpg. |
| |
| * You can also do audio and video conversions at the same time: |
| |
| @example |
| ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2 |
| @end example |
| |
| Converts a.wav to MPEG audio at 22050 Hz sample rate. |
| |
| * You can encode to several formats at the same time and define a |
| mapping from input stream to output streams: |
| |
| @example |
| ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0 |
| @end example |
| |
| Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map |
| file:index' specifies which input stream is used for each output |
| stream, in the order of the definition of output streams. |
| |
| * You can transcode decrypted VOBs: |
| |
| @example |
| ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi |
| @end example |
| |
| This is a typical DVD ripping example; the input is a VOB file, the |
| output an AVI file with MPEG-4 video and MP3 audio. Note that in this |
| command we use B-frames so the MPEG-4 stream is DivX5 compatible, and |
| GOP size is 300 which means one intra frame every 10 seconds for 29.97fps |
| input video. Furthermore, the audio stream is MP3-encoded so you need |
| to enable LAME support by passing @code{--enable-libmp3lame} to configure. |
| The mapping is particularly useful for DVD transcoding |
| to get the desired audio language. |
| |
| NOTE: To see the supported input formats, use @code{ffmpeg -formats}. |
| |
| * You can extract images from a video: |
| |
| @example |
| ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg |
| @end example |
| |
| This will extract one video frame per second from the video and will |
| output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg}, |
| etc. Images will be rescaled to fit the new WxH values. |
| |
| The syntax @code{foo-%03d.jpeg} specifies to use a decimal number |
| composed of three digits padded with zeroes to express the sequence |
| number. It is the same syntax supported by the C printf function, but |
| only formats accepting a normal integer are suitable. |
| |
| If you want to extract just a limited number of frames, you can use the |
| above command in combination with the -vframes or -t option, or in |
| combination with -ss to start extracting from a certain point in time. |
| |
| * You can put many streams of the same type in the output: |
| |
| @example |
| ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio |
| @end example |
| |
| In addition to the first video and audio streams, the resulting |
| output file @file{test12.avi} will contain the second video |
| and the second audio stream found in the input streams list. |
| |
| The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle} |
| options have to be specified immediately after the name of the output |
| file to which you want to add them. |
| @c man end |
| |
| @chapter Invocation |
| |
| @section Syntax |
| |
| The generic syntax is: |
| |
| @example |
| @c man begin SYNOPSIS |
| ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}... |
| @c man end |
| @end example |
| @c man begin DESCRIPTION |
| As a general rule, options are applied to the next specified |
| file. Therefore, order is important, and you can have the same |
| option on the command line multiple times. Each occurrence is |
| then applied to the next input or output file. |
| |
| * To set the video bitrate of the output file to 64kbit/s: |
| @example |
| ffmpeg -i input.avi -b 64k output.avi |
| @end example |
| |
| * To force the frame rate of the output file to 24 fps: |
| @example |
| ffmpeg -i input.avi -r 24 output.avi |
| @end example |
| |
| * To force the frame rate of the input file (valid for raw formats only) |
| to 1 fps and the frame rate of the output file to 24 fps: |
| @example |
| ffmpeg -r 1 -i input.m2v -r 24 output.avi |
| @end example |
| |
| The format option may be needed for raw input files. |
| |
| By default, FFmpeg tries to convert as losslessly as possible: It |
| uses the same audio and video parameters for the outputs as the one |
| specified for the inputs. |
| @c man end |
| |
| @c man begin OPTIONS |
| @section Main options |
| |
| @table @option |
| @item -L |
| Show license. |
| |
| @item -h |
| Show help. |
| |
| @item -version |
| Show version. |
| |
| @item -formats |
| Show available formats, codecs, bitstream filters, protocols, and frame size and frame rate abbreviations. |
| |
| The fields preceding the format and codec names have the following meanings: |
| @table @samp |
| @item D |
| Decoding available |
| @item E |
| Encoding available |
| @item V/A/S |
| Video/audio/subtitle codec |
| @item S |
| Codec supports slices |
| @item D |
| Codec supports direct rendering |
| @item T |
| Codec can handle input truncated at random locations instead of only at frame boundaries |
| @end table |
| |
| @item -f @var{fmt} |
| Force format. |
| |
| @item -i @var{filename} |
| input file name |
| |
| @item -y |
| Overwrite output files. |
| |
| @item -t @var{duration} |
| Restrict the transcoded/captured video sequence |
| to the duration specified in seconds. |
| @code{hh:mm:ss[.xxx]} syntax is also supported. |
| |
| @item -fs @var{limit_size} |
| Set the file size limit. |
| |
| @item -ss @var{position} |
| Seek to given time position in seconds. |
| @code{hh:mm:ss[.xxx]} syntax is also supported. |
| |
| @item -itsoffset @var{offset} |
| Set the input time offset in seconds. |
| @code{[-]hh:mm:ss[.xxx]} syntax is also supported. |
| This option affects all the input files that follow it. |
| The offset is added to the timestamps of the input files. |
| Specifying a positive offset means that the corresponding |
| streams are delayed by 'offset' seconds. |
| |
| @item -title @var{string} |
| Set the title. |
| |
| @item -timestamp @var{time} |
| Set the timestamp. |
| |
| @item -author @var{string} |
| Set the author. |
| |
| @item -copyright @var{string} |
| Set the copyright. |
| |
| @item -comment @var{string} |
| Set the comment. |
| |
| @item -album @var{string} |
| Set the album. |
| |
| @item -track @var{number} |
| Set the track. |
| |
| @item -year @var{number} |
| Set the year. |
| |
| @item -v @var{number} |
| Set the logging verbosity level. |
| |
| @item -target @var{type} |
| Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd", |
| "ntsc-svcd", ... ). All the format options (bitrate, codecs, |
| buffer sizes) are then set automatically. You can just type: |
| |
| @example |
| ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg |
| @end example |
| |
| Nevertheless you can specify additional options as long as you know |
| they do not conflict with the standard, as in: |
| |
| @example |
| ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg |
| @end example |
| |
| @item -dframes @var{number} |
| Set the number of data frames to record. |
| |
| @item -scodec @var{codec} |
| Force subtitle codec ('copy' to copy stream). |
| |
| @item -newsubtitle |
| Add a new subtitle stream to the current output stream. |
| |
| @item -slang @var{code} |
| Set the ISO 639 language code (3 letters) of the current subtitle stream. |
| |
| @end table |
| |
| @section Video Options |
| |
| @table @option |
| @item -b @var{bitrate} |
| Set the video bitrate in bit/s (default = 200 kb/s). |
| @item -vframes @var{number} |
| Set the number of video frames to record. |
| @item -r @var{fps} |
| Set frame rate (Hz value, fraction or abbreviation), (default = 25). |
| @item -s @var{size} |
| Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source). |
| The following abbreviations are recognized: |
| @table @samp |
| @item sqcif |
| 128x96 |
| @item qcif |
| 176x144 |
| @item cif |
| 352x288 |
| @item 4cif |
| 704x576 |
| @item qqvga |
| 160x120 |
| @item qvga |
| 320x240 |
| @item vga |
| 640x480 |
| @item svga |
| 800x600 |
| @item xga |
| 1024x768 |
| @item uxga |
| 1600x1200 |
| @item qxga |
| 2048x1536 |
| @item sxga |
| 1280x1024 |
| @item qsxga |
| 2560x2048 |
| @item hsxga |
| 5120x4096 |
| @item wvga |
| 852x480 |
| @item wxga |
| 1366x768 |
| @item wsxga |
| 1600x1024 |
| @item wuxga |
| 1920x1200 |
| @item woxga |
| 2560x1600 |
| @item wqsxga |
| 3200x2048 |
| @item wquxga |
| 3840x2400 |
| @item whsxga |
| 6400x4096 |
| @item whuxga |
| 7680x4800 |
| @item cga |
| 320x200 |
| @item ega |
| 640x350 |
| @item hd480 |
| 852x480 |
| @item hd720 |
| 1280x720 |
| @item hd1080 |
| 1920x1080 |
| @end table |
| |
| @item -aspect @var{aspect} |
| Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777). |
| @item -croptop @var{size} |
| Set top crop band size (in pixels). |
| @item -cropbottom @var{size} |
| Set bottom crop band size (in pixels). |
| @item -cropleft @var{size} |
| Set left crop band size (in pixels). |
| @item -cropright @var{size} |
| Set right crop band size (in pixels). |
| @item -padtop @var{size} |
| Set top pad band size (in pixels). |
| @item -padbottom @var{size} |
| Set bottom pad band size (in pixels). |
| @item -padleft @var{size} |
| Set left pad band size (in pixels). |
| @item -padright @var{size} |
| Set right pad band size (in pixels). |
| @item -padcolor @var{hex_color} |
| Set color of padded bands. The value for padcolor is expressed |
| as a six digit hexadecimal number where the first two digits |
| represent red, the middle two digits green and last two digits |
| blue (default = 000000 (black)). |
| @item -vn |
| Disable video recording. |
| @item -bt @var{tolerance} |
| Set video bitrate tolerance (in bits, default 4000k). |
| Has a minimum value of: (target_bitrate/target_framerate). |
| In 1-pass mode, bitrate tolerance specifies how far ratecontrol is |
| willing to deviate from the target average bitrate value. This is |
| not related to min/max bitrate. Lowering tolerance too much has |
| an adverse effect on quality. |
| @item -maxrate @var{bitrate} |
| Set max video bitrate (in bit/s). |
| Requires -bufsize to be set. |
| @item -minrate @var{bitrate} |
| Set min video bitrate (in bit/s). |
| Most useful in setting up a CBR encode: |
| @example |
| ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v |
| @end example |
| It is of little use elsewise. |
| @item -bufsize @var{size} |
| Set video buffer verifier buffer size (in bits). |
| @item -vcodec @var{codec} |
| Force video codec to @var{codec}. Use the @code{copy} special value to |
| tell that the raw codec data must be copied as is. |
| @item -sameq |
| Use same video quality as source (implies VBR). |
| |
| @item -pass @var{n} |
| Select the pass number (1 or 2). It is used to do two-pass |
| video encoding. The statistics of the video are recorded in the first |
| pass into a log file (see also the option -passlogfile), |
| and in the second pass that log file is used to generate the video |
| at the exact requested bitrate. |
| On pass 1, you may just deactivate audio and set output to null, |
| examples for Windows and Unix: |
| @example |
| ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL |
| ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null |
| @end example |
| |
| @item -passlogfile @var{prefix} |
| Set two-pass log file name prefix to @var{prefix}, the default file name |
| prefix is ``ffmpeg2pass''. The complete file name will be |
| @file{PREFIX-N.log}, where N is a number specific to the output |
| stream. |
| |
| @item -newvideo |
| Add a new video stream to the current output stream. |
| |
| @end table |
| |
| @section Advanced Video Options |
| |
| @table @option |
| @item -pix_fmt @var{format} |
| Set pixel format. Use 'list' as parameter to show all the supported |
| pixel formats. |
| @item -sws_flags @var{flags} |
| Set SwScaler flags (only available when compiled with swscale support). |
| @item -g @var{gop_size} |
| Set the group of pictures size. |
| @item -intra |
| Use only intra frames. |
| @item -vdt @var{n} |
| Discard threshold. |
| @item -qscale @var{q} |
| Use fixed video quantizer scale (VBR). |
| @item -qmin @var{q} |
| minimum video quantizer scale (VBR) |
| @item -qmax @var{q} |
| maximum video quantizer scale (VBR) |
| @item -qdiff @var{q} |
| maximum difference between the quantizer scales (VBR) |
| @item -qblur @var{blur} |
| video quantizer scale blur (VBR) (range 0.0 - 1.0) |
| @item -qcomp @var{compression} |
| video quantizer scale compression (VBR) (default 0.5). |
| Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0 |
| |
| @item -lmin @var{lambda} |
| minimum video lagrange factor (VBR) |
| @item -lmax @var{lambda} |
| max video lagrange factor (VBR) |
| @item -mblmin @var{lambda} |
| minimum macroblock quantizer scale (VBR) |
| @item -mblmax @var{lambda} |
| maximum macroblock quantizer scale (VBR) |
| |
| These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units, |
| but you may use the QP2LAMBDA constant to easily convert from 'q' units: |
| @example |
| ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext |
| @end example |
| |
| @item -rc_init_cplx @var{complexity} |
| initial complexity for single pass encoding |
| @item -b_qfactor @var{factor} |
| qp factor between P- and B-frames |
| @item -i_qfactor @var{factor} |
| qp factor between P- and I-frames |
| @item -b_qoffset @var{offset} |
| qp offset between P- and B-frames |
| @item -i_qoffset @var{offset} |
| qp offset between P- and I-frames |
| @item -rc_eq @var{equation} |
| Set rate control equation (@pxref{FFmpeg formula |
| evaluator}) (default = @code{tex^qComp}). |
| @item -rc_override @var{override} |
| rate control override for specific intervals |
| @item -me_method @var{method} |
| Set motion estimation method to @var{method}. |
| Available methods are (from lowest to best quality): |
| @table @samp |
| @item zero |
| Try just the (0, 0) vector. |
| @item phods |
| @item log |
| @item x1 |
| @item hex |
| @item umh |
| @item epzs |
| (default method) |
| @item full |
| exhaustive search (slow and marginally better than epzs) |
| @end table |
| |
| @item -dct_algo @var{algo} |
| Set DCT algorithm to @var{algo}. Available values are: |
| @table @samp |
| @item 0 |
| FF_DCT_AUTO (default) |
| @item 1 |
| FF_DCT_FASTINT |
| @item 2 |
| FF_DCT_INT |
| @item 3 |
| FF_DCT_MMX |
| @item 4 |
| FF_DCT_MLIB |
| @item 5 |
| FF_DCT_ALTIVEC |
| @end table |
| |
| @item -idct_algo @var{algo} |
| Set IDCT algorithm to @var{algo}. Available values are: |
| @table @samp |
| @item 0 |
| FF_IDCT_AUTO (default) |
| @item 1 |
| FF_IDCT_INT |
| @item 2 |
| FF_IDCT_SIMPLE |
| @item 3 |
| FF_IDCT_SIMPLEMMX |
| @item 4 |
| FF_IDCT_LIBMPEG2MMX |
| @item 5 |
| FF_IDCT_PS2 |
| @item 6 |
| FF_IDCT_MLIB |
| @item 7 |
| FF_IDCT_ARM |
| @item 8 |
| FF_IDCT_ALTIVEC |
| @item 9 |
| FF_IDCT_SH4 |
| @item 10 |
| FF_IDCT_SIMPLEARM |
| @end table |
| |
| @item -er @var{n} |
| Set error resilience to @var{n}. |
| @table @samp |
| @item 1 |
| FF_ER_CAREFUL (default) |
| @item 2 |
| FF_ER_COMPLIANT |
| @item 3 |
| FF_ER_AGGRESSIVE |
| @item 4 |
| FF_ER_VERY_AGGRESSIVE |
| @end table |
| |
| @item -ec @var{bit_mask} |
| Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of |
| the following values: |
| @table @samp |
| @item 1 |
| FF_EC_GUESS_MVS (default = enabled) |
| @item 2 |
| FF_EC_DEBLOCK (default = enabled) |
| @end table |
| |
| @item -bf @var{frames} |
| Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4). |
| @item -mbd @var{mode} |
| macroblock decision |
| @table @samp |
| @item 0 |
| FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg). |
| @item 1 |
| FF_MB_DECISION_BITS: Choose the one which needs the fewest bits. |
| @item 2 |
| FF_MB_DECISION_RD: rate distortion |
| @end table |
| |
| @item -4mv |
| Use four motion vector by macroblock (MPEG-4 only). |
| @item -part |
| Use data partitioning (MPEG-4 only). |
| @item -bug @var{param} |
| Work around encoder bugs that are not auto-detected. |
| @item -strict @var{strictness} |
| How strictly to follow the standards. |
| @item -aic |
| Enable Advanced intra coding (h263+). |
| @item -umv |
| Enable Unlimited Motion Vector (h263+) |
| |
| @item -deinterlace |
| Deinterlace pictures. |
| @item -ilme |
| Force interlacing support in encoder (MPEG-2 and MPEG-4 only). |
| Use this option if your input file is interlaced and you want |
| to keep the interlaced format for minimum losses. |
| The alternative is to deinterlace the input stream with |
| @option{-deinterlace}, but deinterlacing introduces losses. |
| @item -psnr |
| Calculate PSNR of compressed frames. |
| @item -vstats |
| Dump video coding statistics to @file{vstats_HHMMSS.log}. |
| @item -vstats_file @var{file} |
| Dump video coding statistics to @var{file}. |
| @item -vhook @var{module} |
| Insert video processing @var{module}. @var{module} contains the module |
| name and its parameters separated by spaces. |
| @item -top @var{n} |
| top=1/bottom=0/auto=-1 field first |
| @item -dc @var{precision} |
| Intra_dc_precision. |
| @item -vtag @var{fourcc/tag} |
| Force video tag/fourcc. |
| @item -qphist |
| Show QP histogram. |
| @item -vbsf @var{bitstream_filter} |
| Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump". |
| @example |
| ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264 |
| @end example |
| @end table |
| |
| @section Audio Options |
| |
| @table @option |
| @item -aframes @var{number} |
| Set the number of audio frames to record. |
| @item -ar @var{freq} |
| Set the audio sampling frequency (default = 44100 Hz). |
| @item -ab @var{bitrate} |
| Set the audio bitrate in bit/s (default = 64k). |
| @item -ac @var{channels} |
| Set the number of audio channels (default = 1). |
| @item -an |
| Disable audio recording. |
| @item -acodec @var{codec} |
| Force audio codec to @var{codec}. Use the @code{copy} special value to |
| specify that the raw codec data must be copied as is. |
| @item -newaudio |
| Add a new audio track to the output file. If you want to specify parameters, |
| do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..). |
| |
| Mapping will be done automatically, if the number of output streams is equal to |
| the number of input streams, else it will pick the first one that matches. You |
| can override the mapping using @code{-map} as usual. |
| |
| Example: |
| @example |
| ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio |
| @end example |
| @item -alang @var{code} |
| Set the ISO 639 language code (3 letters) of the current audio stream. |
| @end table |
| |
| @section Advanced Audio options: |
| |
| @table @option |
| @item -atag @var{fourcc/tag} |
| Force audio tag/fourcc. |
| @item -absf @var{bitstream_filter} |
| Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp". |
| @end table |
| |
| @section Subtitle options: |
| |
| @table @option |
| @item -scodec @var{codec} |
| Force subtitle codec ('copy' to copy stream). |
| @item -newsubtitle |
| Add a new subtitle stream to the current output stream. |
| @item -slang @var{code} |
| Set the ISO 639 language code (3 letters) of the current subtitle stream. |
| @item -sbsf @var{bitstream_filter} |
| Bitstream filters available are "mov2textsub", "text2movsub". |
| @example |
| ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt |
| @end example |
| @end table |
| |
| @section Audio/Video grab options |
| |
| @table @option |
| @item -vc @var{channel} |
| Set video grab channel (DV1394 only). |
| @item -tvstd @var{standard} |
| Set television standard (NTSC, PAL (SECAM)). |
| @item -isync |
| Synchronize read on input. |
| @end table |
| |
| @section Advanced options |
| |
| @table @option |
| @item -map @var{input_stream_id}[:@var{sync_stream_id}] |
| Set stream mapping from input streams to output streams. |
| Just enumerate the input streams in the order you want them in the output. |
| @var{sync_stream_id} if specified sets the input stream to sync |
| against. |
| @item -map_meta_data @var{outfile}:@var{infile} |
| Set meta data information of @var{outfile} from @var{infile}. |
| @item -debug |
| Print specific debug info. |
| @item -benchmark |
| Add timings for benchmarking. |
| @item -dump |
| Dump each input packet. |
| @item -hex |
| When dumping packets, also dump the payload. |
| @item -bitexact |
| Only use bit exact algorithms (for codec testing). |
| @item -ps @var{size} |
| Set packet size in bits. |
| @item -re |
| Read input at native frame rate. Mainly used to simulate a grab device. |
| @item -loop_input |
| Loop over the input stream. Currently it works only for image |
| streams. This option is used for automatic FFserver testing. |
| @item -loop_output @var{number_of_times} |
| Repeatedly loop output for formats that support looping such as animated GIF |
| (0 will loop the output infinitely). |
| @item -threads @var{count} |
| Thread count. |
| @item -vsync @var{parameter} |
| Video sync method. Video will be stretched/squeezed to match the timestamps, |
| it is done by duplicating and dropping frames. With -map you can select from |
| which stream the timestamps should be taken. You can leave either video or |
| audio unchanged and sync the remaining stream(s) to the unchanged one. |
| @item -async @var{samples_per_second} |
| Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps, |
| the parameter is the maximum samples per second by which the audio is changed. |
| -async 1 is a special case where only the start of the audio stream is corrected |
| without any later correction. |
| @item -copyts |
| Copy timestamps from input to output. |
| @item -shortest |
| Finish encoding when the shortest input stream ends. |
| @item -dts_delta_threshold |
| Timestamp discontinuity delta threshold. |
| @item -muxdelay @var{seconds} |
| Set the maximum demux-decode delay. |
| @item -muxpreload @var{seconds} |
| Set the initial demux-decode delay. |
| @end table |
| |
| @section Preset files |
| |
| A preset file contains a sequence of @var{option}=@var{value} pairs, |
| one for each line, specifying a sequence of options which would be |
| awkward to specify on the command line. Lines starting with the hash |
| ('#') character are ignored and are used to provide comments. Check |
| the @file{ffpresets} directory in the FFmpeg source tree for examples. |
| |
| Preset files are specified with the @code{vpre}, @code{apre} and |
| @code{spre} options. The options specified in a preset file are |
| applied to the currently selected codec of the same type as the preset |
| option. |
| |
| The argument passed to the preset options identifies the preset file |
| to use according to the following rules. |
| |
| First ffmpeg searches for a file named @var{arg}.ffpreset in the |
| directories @file{$HOME/.ffmpeg}, and in the datadir defined at |
| configuration time (usually @file{PREFIX/share/ffmpeg}) in that |
| order. For example, if the argument is @code{libx264-max}, it will |
| search for the file @file{libx264-max.ffpreset}. |
| |
| If no such file is found, then ffmpeg will search for a file named |
| @var{codec_name}-@var{arg}.ffpreset in the above-mentioned |
| directories, where @var{codec_name} is the name of the codec to which |
| the preset file options will be applied. For example, if you select |
| the video codec with @code{-vcodec libx264} and use @code{-vpre max}, |
| then it will search for the file @file{libx264-max.ffpreset}. |
| |
| Finally, if the above rules failed and the argument specifies an |
| absolute pathname, ffmpeg will search for that filename. This way you |
| can specify the absolute and complete filename of the preset file, for |
| example @file{./ffpresets/libx264-max.ffpreset}. |
| |
| @node FFmpeg formula evaluator |
| @section FFmpeg formula evaluator |
| |
| When evaluating a rate control string, FFmpeg uses an internal formula |
| evaluator. |
| |
| The following binary operators are available: @code{+}, @code{-}, |
| @code{*}, @code{/}, @code{^}. |
| |
| The following unary operators are available: @code{+}, @code{-}, |
| @code{(...)}. |
| |
| The following statements are available: @code{ld}, @code{st}, |
| @code{while}. |
| |
| The following functions are available: |
| @table @var |
| @item sinh(x) |
| @item cosh(x) |
| @item tanh(x) |
| @item sin(x) |
| @item cos(x) |
| @item tan(x) |
| @item atan(x) |
| @item asin(x) |
| @item acos(x) |
| @item exp(x) |
| @item log(x) |
| @item abs(x) |
| @item squish(x) |
| @item gauss(x) |
| @item mod(x, y) |
| @item max(x, y) |
| @item min(x, y) |
| @item eq(x, y) |
| @item gte(x, y) |
| @item gt(x, y) |
| @item lte(x, y) |
| @item lt(x, y) |
| @item bits2qp(bits) |
| @item qp2bits(qp) |
| @end table |
| |
| The following constants are available: |
| @table @var |
| @item PI |
| @item E |
| @item iTex |
| @item pTex |
| @item tex |
| @item mv |
| @item fCode |
| @item iCount |
| @item mcVar |
| @item var |
| @item isI |
| @item isP |
| @item isB |
| @item avgQP |
| @item qComp |
| @item avgIITex |
| @item avgPITex |
| @item avgPPTex |
| @item avgBPTex |
| @item avgTex |
| @end table |
| |
| @c man end |
| |
| @ignore |
| |
| @setfilename ffmpeg |
| @settitle FFmpeg video converter |
| |
| @c man begin SEEALSO |
| ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}. |
| @c man end |
| |
| @c man begin AUTHOR |
| Fabrice Bellard |
| @c man end |
| |
| @end ignore |
| |
| @section Protocols |
| |
| The file name can be @file{-} to read from standard input or to write |
| to standard output. |
| |
| FFmpeg also handles many protocols specified with an URL syntax. |
| |
| Use 'ffmpeg -formats' to see a list of the supported protocols. |
| |
| The protocol @code{http:} is currently used only to communicate with |
| FFserver (see the FFserver documentation). When FFmpeg will be a |
| video player it will also be used for streaming :-) |
| |
| @chapter Tips |
| |
| @itemize |
| @item For streaming at very low bitrate application, use a low frame rate |
| and a small GOP size. This is especially true for RealVideo where |
| the Linux player does not seem to be very fast, so it can miss |
| frames. An example is: |
| |
| @example |
| ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm |
| @end example |
| |
| @item The parameter 'q' which is displayed while encoding is the current |
| quantizer. The value 1 indicates that a very good quality could |
| be achieved. The value 31 indicates the worst quality. If q=31 appears |
| too often, it means that the encoder cannot compress enough to meet |
| your bitrate. You must either increase the bitrate, decrease the |
| frame rate or decrease the frame size. |
| |
| @item If your computer is not fast enough, you can speed up the |
| compression at the expense of the compression ratio. You can use |
| '-me zero' to speed up motion estimation, and '-intra' to disable |
| motion estimation completely (you have only I-frames, which means it |
| is about as good as JPEG compression). |
| |
| @item To have very low audio bitrates, reduce the sampling frequency |
| (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3). |
| |
| @item To have a constant quality (but a variable bitrate), use the option |
| '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst |
| quality). |
| |
| @item When converting video files, you can use the '-sameq' option which |
| uses the same quality factor in the encoder as in the decoder. |
| It allows almost lossless encoding. |
| |
| @end itemize |
| |
| @bye |