FFMPEG An Intermediate Guide/Flags Flags

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This should help define the flags command in FFMPEG.

The flag command is used to by calling "-flag", followed by a single space and then all flags with a plus "+" or minus "-" sign preceding each indicating active or inactive flag respectively.

mv4[edit]

Affects: Encoding, Video

use four motion vector by macroblock (mpeg4)

obmc[edit]

Affects: Encoding, Video

use overlapped block motion compensation (h263+)


qpel[edit]

Affects: Encoding, Video

use 1/4 pel motion compensation


loop[edit]

Affects: Encoding, Video

use loop filter


gmc[edit]

Affects: Encoding, Video

use gmc


mv0[edit]

Affects: Encoding, Video

always try a mb with mv=<0,0>


part[edit]

Affects: Encoding, Video

use data partitioning


gray[edit]

Affects: Encoding, Decoding, Video

only decode/encode grayscale


psnr[edit]

Affects: Encoding, Video

error[?] variables will be set during encoding


naq[edit]

Affects: Encoding, Video

normalize adaptive quantization


low_delay[edit]

Affects: Encoding, Video

force low delay


alt[edit]

Affects: Encoding, Video

enable alternate scantable (mpeg2/mpeg4)


global_header[edit]

Affects: Encoding, Video, Audio

place global headers in extradata instead of every keyframe


bitexact[edit]

Affects: Encoding, Decoding, Video, Audio, S (not sure but assuming subtitles)

EDVAS use only bitexact stuff (except (i)dct)


aic[edit]

Affects: Encoding, Video

h263 advanced intra coding / mpeg4 ac prediction


umv[edit]

Affects: Encoding, Video

use unlimited motion vectors

umv is no longer a flag option

cbp[edit]

Affects: Encoding, Video

use rate distortion optimization for cbp


qprd[edit]

Affects: Encoding, Video

use rate distortion optimization for qp selection


aiv[edit]

Affects: Encoding, Video

h263 alternative inter vlc


slice[edit]

Affects: Encoding, Video

slice is no longer a flag option

ilme[edit]

Affects: Encoding, Video Codecs/Containers: MPEG 2 and MPEG 4. Interlaced fotage

Force InterLaced Motion Estimation, this is only necessary if you are working with interlaced video. It will force FFMPEG to maintain Quality with interlace footage. If you wish to deinterlace your footage please use '-deinterlace' option, but this will cause a quality lose in the video. Rule of thumb is anything intended is for television is interlace, any other delivery format is most likely progressive.


ildct[edit]

Affects: Encoding, Video

Use when encoding Interlaced footage to ensure that FFMPEG doesn't field merge your DCT. Only affects Interlaced footage.


scan_offset[edit]

Affects: Encoding, Video

will reserve space for svcd scan offset user data


cgop[edit]

Affects: Encoding, Video

closed gop

Problems[edit]

trell[edit]

Trell is no longer a flag option, please use -trellis instead.