ffmpeg--what is it? Do I need it?

[erik]

ffmpeg (running on many platforms including XP, W2K) is used to transcode between various formats such as mpeg, divx and avi.

If you do not need to transcode (such as convert mpeg into divx for size reduction in archiving) you do not need ffmpeg

You can find below all the ffmpeg options, this should give an impression.

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usage: ffmpeg [[infile options] -i infile]... {[outfile options] outfile}...
Hyper fast Audio and Video encoder

Main options:
-L show license
-h show help
-version show version
-formats show available formats, codecs, protocols, ...
-f fmt force format
-img img_fmt force image format
-i filename input file name
-y overwrite output files
-t duration set the recording time
-ss time_off set the start time offset
-itsoffset time_off set the input ts offset
-title string set the title
-timestamp time set the timestamp
-author string set the author
-copyright string set the copyright
-comment string set the comment
-v verbose control amount of logging
-target type specify target file type ("vcd", "svcd", "dvd", "dv", "pal-vcd", "ntsc-svcd", ...)
-dframes number set the number of data frames to record
-hq activate high quality settings

Video options:
-b bitrate set video bitrate (in kbit/s)
-vframes number set the number of video frames to record
-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)
-croptop size set top crop band size (in pixels)
-cropbottom size set bottom crop band size (in pixels)
-cropleft size set left crop band size (in pixels)
-cropright size set right crop band size (in pixels)
-padtop size set top pad band size (in pixels)
-padbottom size set bottom pad band size (in pixels)
-padleft size set left pad band size (in pixels)
-padright size set right pad band size (in pixels)
-padcolor color set color of pad bands (Hex 000000 thru FFFFFF)
-vn disable video
-bt tolerance set video bitrate tolerance (in kbit/s)
-maxrate bitrate set max video bitrate tolerance (in kbit/s)
-minrate bitrate set min video bitrate tolerance (in kbit/s)
-bufsize size set ratecontrol buffer size (in kByte)
-vcodec codec force video codec ('copy' to copy stream)
-sameq use same video quality as source (implies VBR)
-pass n select the pass number (1 or 2)
-passlogfile file select two pass log file name

Advanced Video options:
-pix_fmt format set pixel format
-g gop_size set the group of picture size
-intra use only intra frames
-qscale q use fixed video quantiser scale (VBR)
-qmin q min video quantiser scale (VBR)
-qmax q max video quantiser scale (VBR)
-lmin lambda min video lagrange factor (VBR)
-lmax lambda max video lagrange factor (VBR)
-mblmin q min macroblock quantiser scale (VBR)
-mblmax q max macroblock quantiser scale (VBR)
-qdiff q max difference between the quantiser scale (VBR)
-qblur blur video quantiser scale blur (VBR)
-qsquish squish how to keep quantiser between qmin and qmax (0 = clip, 1 = use differentiable function)
-qcomp compression video quantiser scale compression (VBR)
-rc_init_cplx complexity initial complexity for 1-pass encoding
-b_qfactor factor qp factor between p and b frames
-i_qfactor factor qp factor between p and i frames
-b_qoffset offset qp offset between p and b frames
-i_qoffset offset qp offset between p and i frames
-ibias bias intra quant bias
-pbias bias inter quant bias
-rc_eq equation set rate control equation
-rc_override override rate control override for specific intervals
-me method set motion estimation method
-dct_algo algo set dct algo
-idct_algo algo set idct algo
-me_threshold motion estimaton threshold
-mb_threshold macroblock threshold
-er n set error resilience
-ec bit_mask set error concealment
-bf frames use 'frames' B frames
-mbd mode macroblock decision
-mbcmp cmp function macroblock compare function
-ildctcmp cmp function ildct compare function
-subcmp cmp function subpel compare function
-cmp cmp function fullpel compare function
-precmp cmp function pre motion estimation compare function
-preme pre motion estimation
-lelim elim single coefficient elimination threshold for luminance (negative values also consider DC coefficient)
-celim elim single coefficient elimination threshold for chrominance (negative values also consider DC coefficient)
-lumi_mask luminance masking
-dark_mask darkness masking
-scplx_mask spatial complexity masking
-tcplx_mask temporal complexity masking
-p_mask inter masking
-4mv use four motion vector by macroblock (MPEG4)
-obmc use overlapped block motion compensation (h263+)
-lf use loop filter (h263+)
-part use data partitioning (MPEG4)
-bug param workaround not auto detected encoder bugs
-strict strictness how strictly to follow the standards
-deinterlace deinterlace pictures
-ildct force interlaced dct support in encoder (MPEG2/MPEG4)
-ilme force interlaced me support in encoder (MPEG2/MPEG4)
-psnr calculate PSNR of compressed frames
-vstats dump video coding statistics to file
-vhook module insert video processing module
-aic enable Advanced intra coding (h263+)
-aiv enable Alternative inter vlc (h263+)
-umv enable Unlimited Motion Vector (h263+)
-ssm enable Slice Structured mode (h263+)
-alt enable alternate scantable (MPEG2/MPEG4)
-qprd
-cbp
-trell enable trellis quantization
-mv0 try to encode each MB with MV=<0,0> and choose the better one (has no effect if mbd=0)
-naq normalize adaptive quantization
-cgop closed gop
-sgop strict gop
-noout skip bitstream encoding
-scan_offset enable SVCD Scan Offset placeholder
-qpel enable 1/4-pel
-intra_matrix matrix specify intra matrix coeffs
-inter_matrix matrix specify inter matrix coeffs
-top top=1/bottom=0/auto=-1 field first
-nr noise reduction
-qns quantization noise shaping
-sc_threshold threshold scene change threshold
-me_range range limit motion vectors range (1023 for DivX player)
-dc precision intra_dc_precision
-coder coder type
-context context model
-pred prediction method
-vprofile profile
-vlevel level
-nssew weight
-subq
-lowres
-vtag fourcc/tag force video tag/fourcc
-skip_threshold threshold frame skip threshold
-skip_factor factor frame skip factor
-skip_exp exponent frame skip exponent
-skip_cmp compare function frame skip compare function

Audio options:
-aframes number set the number of audio frames to record
-ab bitrate set audio bitrate (in kbit/s)
-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)

Advanced Audio options:
-atag fourcc/tag force audio tag/fourcc

Audio/Video grab options:
-vd device set video grab device
-vc channel set video grab channel (DV1394 only)
-tvstd standard set television standard (NTSC, PAL (SECAM))
-ad device set audio device
-grab format request grabbing using
-gd device set grab device

Advanced options:
-map filetream set input stream mapping
-map_meta_data outfile:infile set meta data information of outfile from infile
-debug print specific debug info
-vismv visualize motion vectors
-benchmark add timings for benchmarking
-dump dump each input packet
-hex when dumping packets, also dump the payload
-bitexact only use bit exact algorithms (for codec testing)
-re read input at native frame rate
-loop loop (current only works with images)
-threads count thread count
-vsync video sync method
-async audio sync method
-copyts copy timestamps
-ps size set packet size in bits
-error rate error rate
-muxrate rate set mux rate
-packetsize size set packet size
-muxdelay seconds set the maximum demux-decode delay
-muxpreload seconds set the initial demux-decode delay