FFMPEG An Intermediate Guide/Flags
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 (deprecated) edit
Affects: Encoding, Video
alt used to be flag, but moved was to be a private option (named alternate_scan) for the mpeg2video and MPEG4 encoders.
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.