Man Linux: Main Page and Category List

NAME

       mpeg2enc - MPEG-1/2 encoder

SYNOPSIS

       mpeg2enc  [-v|--verbose  num]  [-M|--multi-thread num_CPU] [-f|--format
       mpeg_profile]       [-l|--level]h|high|m|main       [-b|--video-bitrate
       bitrate_kbps] [-V|--video-buffer video_buf_size_kB] [-T|--target-still-
       size  still_size_kB]  [-q|--quantisation  quantisation]   [-r|--motion-
       search-radius     motion_search_radius]    [-Q|--quantisation-reduction
       -4.0..5.0]          [-X|--quant-reduction-max-var          0.0..2500.0]
       [-p|--3-2-pulldown]  [-I|--interlace-mode 0|1|2] [-s|--sequence-header-
       every-gop]    [-g|--min-gop-size    min_gop_size]    [-G|--max-gop-size
       max_gop_size]  [-P|--force-b-b-p]  [-n|--video-norm n|p|s] [-F|--frame-
       rate frame_rate_code]  [-x|--display-hsize]  32..38383]  [-y|--display-
       vsize] 32..38383] [-a|--aspect aspect_ratio_code] [-z|--playback-field-
       order  b|t]   [-4|--reduction-4x4   1..4]   [-2|--reduction-2x2   1..4]
       [-S|--sequence-length   size_MB]  [-B|--nonvideo-bitrate  bitrate_kbps]
       [-N|--reduce-hf  0.0..2.0]  [-D|--intra_dc_prec  8..11]  [-H|--keep-hf]
       [-d|--no-dummy-svcd-SOF]   [-C|--correct-svcd-hds]   [--no-constraints]
       [-K|--custom-quant-matrices                    kvcd|tmpgenc|default|hi-
       res|file=inputfile|help]  [-E|--unit-coeff-elim  -40..40]  [-R|--b-per-
       refframe      0..2]      [--no-altscan-mpeg2]       [--dualprime-mpeg2]
       [-A|--ratecontroller    0..1]    [-u|--cbr]    [--chapters   frame,...]
       [-?|--help] -o|--output filename

DESCRIPTION

       mpeg2enc is heavily enhanced derivative of the MPEG Software Simulation
       Group’s  MPEG-2  reference  encoder.   It  accepts  streams in a simple
       planar YUV format  "YUV4MPEG"  produced  by  the  lav2yuv  and  related
       filters  (e.g. yuvscaler(1)) from the mjpegtools(1) package.  An output
       plug-in to the mpeg2dec(1) MPEG decoder is available to permit its  use
       in  transcoding  applications. The encoder currently fully supports the
       generation of  elementary  MPEG-1,  progressive  and  interlaced  frame
       MPEG-2  streams.   Field  encoded  MPEG-2  is  also possible but is not
       currently maintained or supported.

       For most purposes  this  elementary  stream  output  will  need  to  be
       multiplexed  with  one  or  more  audio  streams into a program/systems
       stream using the mplex(1) tool.

       Note that although this manual page aims to explain how mpeg2enc can be
       used  effectively  it  is  not  intended as an introduction to MPEG-1/2
       video which is a fairly complex topic in its own right.  The MPEG video
       format  is  a somewhat baroque standard with many many options, not all
       of which necessarily easy to explain or even particular useful  in  the
       context of a software encoder.

       Much  useful  practical  information  for  novices  can be found in the
       mjpeg-HOWTO document that should have been installed with mjpegtools(1)
       package.   Further  information  and  useful supporting software can be
       found on the mjpegtools web-site:

              http://mjpeg.sourceforge.net

SELECTING THE MPEG PROFILE

       Set the MPEG profile to use.  The MPEG standards support a vast  number
       of  options.   In  practice,  different applications of the MPEG format
       place additional constraints of the form the MPEG stream.  Setting this
       flag selects the kind of stream to produce.

       -f|--format 0
               -       Generic MPEG1.

               A basic MPEG-1 profile that lets most parameters
               be  adjusted for particular applications using the other flags.
               Typical applications would be to  produce  a  variable  bitrate
       MPEG-1
               stream with big buffers and a high data-rate software playback
               on a computer.

       -f|--format 1
               -       Standard VCD.

       An  MPEG1  profile  exactly to the VCD2.0 specification.  Flag settings
       that would  result  in  a  non-standard  stream  structure  are  simply
       ignored.

       -f|--format 2
               -       User VCD.

       As  for  profile 2 but bitrate and video buffer size can be set to non-
       standard values. Frame size may also  be  non-standard.   Bit-rate  and
       buffer sizes default to those for standard VCD.

       -f|--format 3
               -       Generic MPEG2.

       A  basic  MPEG-2  profile  that  lets  most  parameters be adjusted for
       particular applications using the other  flags.   Typical  applications
       would be to produce a MPEG-2 stream with big buffers and long GOP’s for
       software playback on a computer.

       -f|--format 4
               -       Standard SVCD.

       An MPEG-2 profile exactly to the SVCD2.0 specification.  Flag  settings
       that  would  result  in  a  non-standard  stream  structure  are simply
       ignored.

       -f|--format 5
               -       Non-standard SVCD.

       As for profile  4  but  bitrate,  video  buffer  size,  GOP  sizes  and
       structure  can  be  set  to non-standard values. Frame size may also be
       non-standard.  Bit-rate and buffer sizes default to those for  standard
       SVCD.

       -f|--format 6
               -       VCD Stills sequence.

       Encodes the special style of MPEG stream used for still images on VCDs.
       To use this profile you must set the target size you wish  to  compress
       the  images  to  using the -T flag.   Reasonable values are around 35KB
       for standard resolution stills (352 wide) and 120KB for high resolution
       stills (704 wide).

       -f|--format 7
               -       SVCD Stills sequence.

       Encodes  the  special  style  of  MPEG  stream used for still images on
       SVCDs.  Both standard (480 wide) and high resolution (704 wide)  images
       are  supported.  As  with VCD stills you select how big each compressed
       still should be using the -T flag.

       -f|--format 8
               -       DVD MPEG-2 for ’dvdauthor’

       This version adds special dummy  navigation  packets  into  the  output
       stream  that  the  dvdauthor  tool  fills  in to make a proper .VOB for
       authoring.  Bit-rate defaults to 7500kbps, buffer sizes to the  maximum
       permitted by the DVD specification.

       -f|--format 9
               -       DVD MPEG-2.

       Just  a  very  basic implementation. Useful with DXR2 board and similar
       hardware that can decode MPEG-2 only if it is presented in a  DVD  like
       form.   Bit-rate  defaults  to  7500kbps,  buffer  sizes to the maximum
       permitted by the DVD specification.

       -f|--format 10
               -       ATSC 480i

       -f|--format 11
               -       ATSC 480p

       -f|--format 12
               -       ATSC 720p

       -f|--format 13
               -       ATSC 1080i

GENERAL FUNCTION LETTERS

       -v|--verbose num

       Set verbosity level to  num.   0  =  warnings  and  errors  only,  1  =
       information as well, 2=really verbose.

       -K|--custom-quant-matriceskvcd|tmpgenc|
        default | hi-res | file=inputfile | help

       Specify  which  quantisation  matrices  to  use instead of the defaults
       (which can be specified by using "-K default").   Using "-K hi-res"  is
       identical  to  using  the  -H  option. The value kvcd uses the Kvcd.Net
       matrices from  http://www.kvcd.net/;  the  value  tmpgenc  invokes  the
       TMPGEnc  matrices  from  http://www.tmpgenc.net/e_main.html. On average
       (this depends on the source material), the tmpgenc  tables  reduce  the
       average  bitrate  by  about  10%  and the kvcd tables reduce bitrate by
       about 16% (compared to the default tables).

       -E|--unit-coeff-elim -40..40

       Specify when a special ’unit coefficient elimination’ algorithm  should
       be  applied  to  the encoded picture blocks.  Basically, this procedure
       forces blocks of a type that  don’t  carry  much  information  but  are
       expensive  to  encode  to be simply skipped.  The larger the number the
       more potentially visible this skipping is likely to  be  but  the  more
       compression  is  boosted.  A negative value means that all coefficients
       are  zeroed,  positive  means  only  texture  but  not  base  intensity
       coefficients  are zeroed.  Values of around 10 or -10 seem to work well
       with high quality source material. For noisier  material  it  might  be
       worth trying 20 or -20.

       -R|--b-per-refframe 0..2

       Specify  how  many  bi-directionally (B type) difference-encoded frames
       should be encoded between reference (I or P) frames.  The default is  0
       except  for  VCD  encoding  where  it  is 2 B frames as required by the
       standard.   Experts  differ  on  how  much  using  B  frames   improves
       compression.  In  practice  unless  you have really clean material they
       tend to be fairly useless and  sometimes  even  harmful.   Encoding  is
       significantly  faster  and  uses less memory if no B frames are encoded
       and compression is rarely more than marginally worse.

       -?|--help

       Display a synopsis of the command syntax.

FUNCTION LETTERS ADJUSTING THE SELECTED PROFILE

       N.b. If the profile you have selected sets particular values for  these
       parameters  it  will  over-ride these adjustment flags.  In particular,
       there is almost nothing that can be adjusted for the standard  VCD  and
       SVCD profiles.

       -b|--video-bitrate num

       The  bitrate  of  the output video stream in kBits/sec.  The default is
       exactly the bitrate required for  VCD  streams.   If  variable  bitrate
       (VBR)  mode  has  been selected (see the -q option) this is the maximum
       bitrate of the stream. NOTE: By default MPEG-2 streams (-f 3, 4,  5,  8
       and  9  are VBR.  Use the --cbr option for generating CBR (Constant Bit
       Rate) streams.

       -A|--ratecontroller 0..1

       Specify which of the rate control algorithms to use.   Default is 0.

       -V|--video-buffer num

       The maximum video buffer usage required to decode the stream in KBytes.
       The default is 46KB the (tiny) size specified for VCD.  The size to use
       for SVCD is the (more reasonable) 230KB.  If you  are  encoding  for  a
       half-decent  software decoder it makes sense to push this up to 500K or
       more.

       -T|--target-still-size num

       Set the target size for (S)VCD still images in KB.

       -s|--sequence-header-every-gop

       This flag forces the encoder to generate a  "sequence  header"  at  the
       start  of  every  group-of-pictures.   This  is  needed  by some player
       hardware to support fast forward/rewind/random access functions but  is
       a waste of bits otherwise.

       -d|--no-dummy-svcd-SOF

       The  SVCD  MPEG-2  profile demands that special "Scan OFfset" which are
       (in effect) pointers to the place on the  final  SVCD  disk  where  the
       video for 0.5 and around 5-10 seconds behind and ahead in the stream is
       located.  The intended use  of  this  information  is  to  support"Fast
       forward/Rewind" functions.  Unfortunately, at the time mpeg2enc encodes
       the video it doesn’t know where the video is going to finally  end  up.
       So special dummy "Scan OFfset" values are written which are intended to
       be filled in during the creation of the SVCD image. Currently  the  GNU
       vcdimager  tool  handles this task.  However, in some circumstances the
       dummy  offsets  can  cause  problems.    This  flags   stops   mpeg2enc
       generating them.

       --correct-svcd-hds

       In  the  official  SVCD  standards  the  field  in  the  MPEG-2  header
       information  that  passes  on  the  encoders  "recommended"  horizontal
       resolution  to  decode the stream to is supposed to take the values 540
       (for 4:3 sequences) or 720 (for  16:9  sequences).   In  practice  many
       players  don’t work unless the value is 480. This flag, forces mpeg2enc
       to follow the official standard. It is worth trying if  16:9  sequences
       play at 4:3 aspect ratio.

       --no-constraints

       This  flag deactivates all constraints for the maximum video samplerate
       or video resolution. Its purpose is to allow the  encoding  of  unusual
       resolutions  of MPEG-video (e.g. 2200 x 576, 160 degrees FOV VR-theatre
       MPEG movies), but should be used with care: It can possible  circumvent
       a  number  of  other  security  checks, and untested settings can cause
       mpeg2enc to crash in this mode.  -l|--level h|high|m|main

       This flag allows the MPEG-2  implementation  level  against  which  the
       coding  parameters  are checked to be set.  You may need to set this to
       ’high’ if you’re encoding HDTV material.

       --no-altscan-mpeg2

       This flag deactivates  the  use  of  the  ’alternate’  macroblock  scan
       pattern  for  MPEG2  encoding.  Normally this pattern is used but a few
       elderly software decoders had  bugs  relating  to  this  feature.   You
       should never need to use this flag.

       --dualprime-mpeg2

       MPEG-2  supports  a  special  motion  estimation mode (DPME, Dual Prime
       Motion Estimation) for I/P-frame only streams that can somewhat improve
       compression.   A  number of players (both hardware and software) do not
       support this mode.  Those players  may or may not be  MPEG-2  compliant
       depending if DPME is an option or not in the MPEG-2 specs.  If you need
       to generate content for  such players (e.g. Ogle or Apple’s DVD  player
       application)  you  should NOT turn on dualprime-mpeg2!  Surprisingly at
       least one hardware/set-top player is known to be allergic to DPME being
       used.

       -z|--playback-field-order b|t

       This flag overrides the field-order specified in the interlacing tag of
       the input stream header. (If you  need  this  option,  it  indicates  a
       problem  in  the capturing/encoding process where the temporal order of
       the two fields in each frame has been mislabeled. The effect of this is
       weird  "juddering"  when  playing  back  the  stream on a TV. Check the
       mjpeg-howto for more information about interlacing problems.)

OPTION LETTERS CONTROLLING VIDEO PARAMETERS

       -n|--video-norm n|p|s

       Force the input stream to be treated as  NTSC|PAL|SECAM  regardless  of
       what  the  stream  header  might suggest.  Basically this just sets the
       defaults for a bunch of other options.

       -F|--frame-rate num

       Set the frame-rate of the output-stream.  By  default,  this  value  is
       inferred  from the input header. Currently only the standard MPEG rates
       are  supported.   Eventually  more-or-less  arbitrary  rates  will   be
       possible.
        0 - illegal
        1 - 24000.0/1001.0 (NTSC 3:2 pulldown converted FILM)
        2 - 24.0 (NATIVE FILM)
        3 - 25.0 (PAL/SECAM VIDEO / converted FILM)
        4 - 30000.0/1001.0 (NTSC VIDEO)
        5 - 30.0
        6 - 50.0 (PAL FIELD RATE)
        7 - 60000.0/1001.0 (NTSC FIELD RATE)
        8 - 60.0

       -a|--aspect num

       Set  the  playback  aspect ratio code of the encoded video. By default,
       this value is inferred from the input header.
        1 - 1  - 1:1 display
        2 - 2  - 4:3 display
        3 - 3  - 16:9 display
        4 - 4  - 2.21:1 display

              For MPEG-2 the specified aspect ratios are  used  directly.  For
              MPEG-1  mpeg2enc  infers  the  MPEG-1 pixel aspect code from the
              video norm specified and the specified playback aspect ratio.

       -x|--display-hsize num

       -y|--display-vsize num

       These set the display-horizontal-size and  display-vertical-size  hints
       in   the  MPEG-2.   By  default  these  are  simply  the  encode  frame
       dimensions.  However, if they are set to different  values  the  player
       gets  a  hint  that  the  appropriate  ’black bars’ or cropping/scaling
       should be performed. The main use for these  parameters  is  to  set  a
       display-vertical-size  of 1080 for HDTV 1080i or 1080p material.  Here,
       since the frame height has to be a multiple of 16,  the  encoded  frame
       height  is  forced  to be 1088, even though HDTV standards specify only
       1080 lines of picture content.  Standards committees ... love’ em.

       -p|--3-2-pulldown

       Setting -p only makes sense for 24frame/sec Movie source material.   It
       sets flags in the output stream that tell the decoder to play the movie
       as NTSC 60field/sec video using "3:2 pulldown".  This  is  vastly  more
       efficient  than encoding as 60field/sec video.  The classic application
       is to transcode a PAL-encoded movie (24fps played too fast at 25  fps!)
       into NTSC (see the -f flag).

OPTION LETTERS FOR CONTROLLING COMPRESSION AND SPEED

       -M|--multi-thread num_CPU

       MPEG  encoding is a task that can be split over a small number of CPU’s
       quite efficiently.  Mpeg2enc can  be  internally  set  to  split  major
       processing  tasks  between  a number of concurrent threads.   This flag
       adjusts the multi-threading to the optimum  to  utilise  the  specified
       number of CPU’s.

       It should be noted that even with 1 CPU present some multi-threading is
       performed: frame input takes place  in  parallel  with  encoding.   The
       default  -M  value  is  1.  This allows good performance to be achieved
       when when a seperate machine is being used for pre-processing (decoding
       from  MJPEG,  scaling,  denoising  etc)  with  the final result pipe to
       mpeg2enc (e.g. using rsh or ssh).

       Setting -M 0 disables all multithreading.  This is sometimes useful for
       debugging  or  to  achieve  maximum CPU efficiency on a shared machine.
       Setting -M 3 on a dual-CPU machine will produce slightly faster results
       than -M 2 at the price of slightly less CPU efficiency.  This is useful
       if nothing else needs to be done on the encoding machine.  In  practice
       there  is  little point setting -M greater than 4 even if the CPU’s are
       available due to the fairly coarse-grained  parallelism  used.   Indeed
       there is a hardcoded limit of 4 worker threads.

       The default has been changed to be 0 instead of 1 to avoid the crash at
       end of encoding:

       INFO: [mpeg2enc] Signaling last frame = 499
       mpeg2enc: seqencoder.cc:433: void SeqEncoder::EncodeStream(): Assertion ‘pass1coded.size() == 0’ failed.
       Abort

       -q|--quantisation 1..31

       Minimum quantisation of the output stream.  Quantisation  controls  the
       precision  with  which  image  information  is  encoded.  The lower the
       number the higher the quality but the greater the  required  data-rate.
       NOTE:  on  IA32  systems it is possible to cause artifacting by setting
       the value too low (3 or less) due to arithmetic overflow/truncation  in
       the DCT/iDCT routines.  If this option is set a variable bitrate stream
       is produced.  This is more efficient but variable bitrate MPEG-1 cannot
       be  played  by  some  hardware  decoders  and  is  rejected by some DVD
       authoring packages.  If you intend to use a software decoder  you’d  be
       insane not to use variable bitrate.

       If  this  option  is set without a maximum bitrate being specified then
       quantisation is fixed at the specified value.  It should be noted  that
       not  specifying  a  bitrate  is  probably  an  error  and  may  produce
       unexpected results.

       For MPEG-2 streams a default of 8 is  used  if  -q  is  not  explicitly
       given.  To force constant bitrate streams use --cbr and -b NOT -q!

       -I|--interlace-mode 0|1|2

       Set  the  sequence picture structure and block encoding type for MPEG-2
       streams.  By default, this value is inferred from the  interlacing  tag
       of  the input stream. Setting 0 encodes frame-by-frame with support for
       interlaced video turned off,  and  specifies  that  progressive  chroma
       subsampling  has  been  used.   Setting  1  encodes frame-by-frame with
       interlace-adapted motion compensation and block encoding, and specifies
       that  interlaced  chroma  subsampling  has been used. Setting 2 encodes
       interlaced material field-by-field, which will  produce  more  accurate
       results for highly textured interlaced material with lots of motion, at
       the expense of generally less efficiency.

              This setting should  match  the  interlaced-ness  of  the  input
              stream,  otherwise  chroma  artifacts  may be generated when the
              MPEG stream is played back.

       -g|--min-gop-size num

       -G|--max-gop-size num

       These flags set the minimum and maximum group-of-picture (GOP) size for
       the  output  MPEG  stream.   The  default  values  depend on the output
       format.

       For MPEG-1 (for example VCD) the default is a fixed GOP size of 12  (-g
       and -G are both set to 12).

       For  MPEG-2 the default value of -G (max) is set according to the video
       system: -G 15 for 625 line (PAL) and 18 for 525  line  (NTSC).   If  -g
       (min) has not been specified then the minimum GOP size is set to be one
       half of the maximum (-G).

       To force a fixed GOP size specify both -g and -G with the same value.

       If the minimum and maximum GOP sizes are not  identical  then  mpeg2enc
       will  start  a  new GOP if more than 60% of the macroblocks in a P or B
       frame are Intra encoded.  This ensure big  changes  of  image  coincide
       with  a  fully-encoded  I-frame  by starting  a new GOP.  This can help
       prevent transient "blockiness".

       Reasonable minimum GOP sizes are 6 or 9.  If a minimum is not specified
       but  a  maximum  is  given then the minimum will be set to one half the
       maximum.  A larger GOP size can help reduce the bitrate required for  a
       given  quality.   However,  this  really  only  applies to high-quality
       source material with little noise (e.g. digital video).  For  broadcast
       material  there  is little point setting GOP size much beyond 21 or 24.
       Even with  good  source  material  diminishing  returns  set  in  quite
       rapidly.   Also  it must be noted that specific MPEG-2 formats (such as
       for DVD) are constrained in the maximum allowable GOP size.

       Note: mpeg2enc is currently hard-wired to produce 2  B  frames  between
       each I/P frame unless the GOP size forces less.  This is reasonable for
       medium to high bitrates (>= 1Mbps) but probably  sub-optimal  for  low-
       bitrate encoding.

       -c|--closed-GOPs

       Setting  this  flag  causes  the encoder to generate only "closed" GOPs
       (Groups of Pictures) that can be decoded  without  reference  to  their
       predecessor.   This  is useful for streams that are supposed to be used
       in multi-angle DVD’s and applications where more easily edittable  MPEG
       is required.

       -P|--force-b-b-p

       This flag forces the GOP size selection to choose sizes that ensure 2 B
       frames appear between  adjacent  I/P  frames.   Several  common  MPEG-1
       decoders can’t handle streams where less than 2 B-frames appear between
       I/P frames.

       -Q|--quantisation-reduction -4.0..5.0

       This flag sets the amount quantisation is reduced for blocks containing
       large  amounts  of sharp image detail.  Large values produces efficient
       use of bits but may cause visible artifacting around detailed sections.
       With noisy source material this option may cause a "swimming" effect on
       textured backgrounds as the noise cause the quantisation of  blocks  to
       be  boosted  at  random.   The  default  is 0.0 (off).  See also the -X
       option.

       -X|--quant-reduction-max-var 0.0..2500.0

       Luma variance below which quantisation boost (-Q) is activated.

       -r|--motion-search-radius num

       This flag sets the motion estimation search radius.  For most  purposes
       the  default  (16) should be just fine.  For high-resolution MPEG-2 and
       active scenes it may be worth bumping it up.  However, this  will  make
       encoding  significantly  slower.   There  is  little point reducing the
       radius.  Speed gains are not huge and the  impact  on  quality  can  be
       marked.

       -4|--reduction-4x4 1..4

       -2|--reduction-2x2 1..4

       These  options  control  how  radical  the  encoder is in throwing away
       apparently  poor  candidate  estimates  during  motion  estimation.   A
       setting  of 1 means very few blocks are discarded early which makes for
       slow encoding but quality as good as it gets. A setting of 4 makes  for
       fast  encoding but can impact quality.  The -4 flag controls discarding
       during the initial 4*4 sub-sampled search stage, the -2  flag  controls
       discarding during the secondary 2*2 sub-sampled stage.

              These  flags  are  useful  as  the  speed  quality  trade-off is
              markedly different depending on which CPU you have.   On  modern
              machines  the  impact  on  speed  is  around a factor 2 on older
              machines a factor 3.   The  impact  on  quality  is  around  10%
              quantisation  (0.2  of a bit of precision in encoding textures).
              For most purposes the default settings will be fine.  However on
              P-III  Katmai  etc  -4  2 -2 1 gives a good near-optimum quality
              setting with reasonably speed.

       -N|--reduce-hf num

       Setting this flag adjusts the way texture detail is quantised to reduce
       the precision with which of high-frequency information encoded. This is
       very useful for  mildly  noisy  sources.   If  you  have  really  noisy
       material  the filtering tools available in mjpegtools are a much better
       bet.  The specified number must be in the range 0.0 to  2.0  gives  the
       maxium quantisation boost.  A useful number to use would be 1.5 or 1.0.

       -H|--keep-hf

       Setting this flag makes  the  encoder  encode  as  much  high-frequency
       information  as  possible.    This  is  a  good  setting for maximising
       quality at VCD resolution with good quality low-noise source  material.
       It can also help with "swimmy" material if you can spare the bitrate!

       -D|--intra_dc_prec num

       Specifies  the  precision  of  the DC component. The default is 9. Most
       commercial DVDs use 10. Using 9 instead saves  a  few  bits.  Using  10
       might  help  to  avoid  looking  larger  areas of nearly the same color
       blocky.  A value of 11 is only valid at the next  MPEG-2  profile/level
       so it’s not a currently meaningful value to use.

OPTION LETTERS FOR CHUNKING THE OUTPUT STREAM

       -S|--sequence-length num

       This  flag  allows the target size of individual sequences in the final
       multiplexed stream to be set in MBytes. If set  mpeg2enc keeps track of
       how  large  the eventual stream is getting and inserts a sequence split
       (actually: sequence end / sequence start) into the output  stream  each
       time  it  reaches  the  specified  limit.  The multiplexer mplex(1) can
       recognise these splits and start a new  multiplexed  output  file  each
       time  it  encounters  one.    In  this  way it is easy to automatically
       ensure each component sequence file can be burnt onto a CD-R and  still
       be  played  as  a  stand-alone  MPEG  sequence.    For the SVCD and VCD
       profiles the default target sequence length is 700M  bytes.  For  other
       profiles the default is that sequence length is unlimited.

       -B|--nonvideo-bitrate num

       Since  mpeg2enc  can’t  read minds it cannot know in advance what other
       material will be multiplexed with the output video stream.  Thus to get
       its  calculations  of  where to insert split point right it needs to be
       told the combined data-rate of the other material that is eventually to
       be  multiplexed  with  the  video.   This  flag  allows this rate to be
       specified in K bits/sec.

       A good rule of thumb is to use the total rate of all the other  streams
       plus 1% of the total rate including video.

       -u|--cbr

       Force  the  use  of Constant Bit Rate encoding.  Less than optimal (and
       inefficient in almost all cases) but some folks  insist  on  it.  NOTE:
       this disables (overrides) the use of the -q option!

       It  is  an  error to use this option and not specify a bitrate using -b
       since a constant bitrate of 0 makes no sense.

       --chapters frame,...

       This flag allows you to define chapter points within the  mpeg  stream.
       This  is  most useful when generating DVD video.  Each chapter point is
       specified by frame number, with the first frame being number 0.   Every
       chapter  point  defined will end up at the beginning of a closed GOP as
       an I frame.

SSE, 3D-Now!, MMX !

       mpeg2enc makes extensive use of these SIMD instruction set extension on
       x86 family CPU’s.  The routines used are determined dynamically at run-
       time.  It should be noted that  using  SSE  requires  operating  system
       support.   Old 2.2.x Linux kernels (unless patched ones like RedHat) do
       not have this  and  so  SSE,  although  physically  present,  won’t  be
       activated.

BUGS

       There  should  be  an  option to force GOP sizes that permit 2 B frames
       between I/P frames.  Some decoders (even software)   can’t  handle  the
       case  where I/P frames come back to back or with only 1 B frame between
       them.

       There needs to be a facility for writing dummy user-data fields so that
       the   multiplexer/imager  can  insert  forward/backward  pointers  when
       muxing/imaging an SVCD.

AUTHOR

       This man page was written by Andrew Stevens.  If  you  have  questions,
       remarks,  problems or you just want to contact the developers, the main
       mailing list for the MJPEG-tools is:
         mjpeg-users@lists.sourceforge.net

       For more info, see our website at
         http://mjpeg.sourceforge.net

SEE ALSO

       mplex(1), mp2enc(1),  lavrec(1),  lavplay(1),  lav2yuv(1),  lav2wav(1),
       yuvscaler(1), yuvdenoise(1), y4mdenoise(1), mjpegtools(1)