Example pipeline

1

gst-launch-1.0 videotestsrc num-buffers=1000 ! mpeg2enc ! filesink location=videotestsrc.m1v

Likely, the “format” property is most important, as it selects the type of MPEG stream that is produced. In particular, default property values are dependent on the format, and can even be forcibly restrained to certain pre-sets (and thereby ignored). Note that the (S)VCD profiles also restrict the image size, so some scaling may be needed to accomodate this. The so-called generic profiles (as used in the example above) allow most parameters to be adjusted.

1

gst-launch-1.0 videotestsrc num-buffers=1000 ! videoscale ! mpeg2enc format=1 norm=p ! filesink location=videotestsrc.m1v

GstMpeg2enc

typedef struct {
  GstElement parent;

  /* pads */
  GstPad *sinkpad, *srcpad;

  /* video info for in caps */
  GstVideoInfo vinfo;

  /* options wrapper */
  GstMpeg2EncOptions *options;

  /* general encoding object (contains rest) */
  GstMpeg2Encoder *encoder;

  /* lock for syncing with encoding task */
  GMutex tlock;
  /* with TLOCK */
  /* signals counterpart thread that something changed;
   * buffer ready for task or buffer has been processed */
  GCond cond;
  /* seen eos */
  gboolean eos;
  /* flowreturn obtained by encoding task */
  GstFlowReturn srcresult;
  /* buffer for encoding task */
  GstBuffer *buffer;
  /* timestamps for output */
  GQueue *time;
} GstMpeg2enc;

The “altscan-mpeg2” property

  “altscan-mpeg2”            gboolean

Alternate MPEG-2 block scanning. Disabling this might make buggy players play SVCD streams.

Flags: Read / Write

Default value: TRUE

The “aspect” property

  “aspect”                   GstMpeg2encAspect

Display aspect ratio.

Flags: Read / Write

Default value: Deduce from input

The “b-per-refframe” property

  “b-per-refframe”           gint

Number of B frames between each I/P frame.

Flags: Read / Write

Allowed values: [0,2]

Default value: 0

The “bitrate” property

  “bitrate”                  gint

Compressed video bitrate (kbps).

Flags: Read / Write

Allowed values: [0,40000]

Default value: 1125

The “bufsize” property

  “bufsize”                  gint

Target decoders video buffer size (kB) (default depends on format).

Flags: Read / Write

Allowed values: [20,4000]

Default value: 46

The “closed-gop” property

  “closed-gop”               gboolean

All Group-of-Pictures are closed (for multi-angle DVDs).

Flags: Read / Write

Default value: FALSE

The “constraints” property

  “constraints”              gboolean

Use strict video resolution and bitrate checks.

Flags: Read / Write

Default value: TRUE

The “correct-svcd-hds” property

  “correct-svcd-hds”         gboolean

Force SVCD width to 480 instead of 540/720.

Flags: Read / Write

Default value: FALSE

The “dualprime” property

  “dualprime”                gboolean

Dual Prime Motion Estimation Mode for MPEG-2 I/P-frame only streams. Quite some players do not support this.

Flags: Read / Write

Default value: FALSE

The “dummy-svcd-sof” property

  “dummy-svcd-sof”           gboolean

Generate dummy SVCD scan-data (for vcdimager).

Flags: Read / Write

Default value: TRUE

The “force-b-b-p” property

  “force-b-b-p”              gboolean

Force two B frames between I/P frames when closing GOP boundaries.

Flags: Read / Write

Default value: FALSE

The “format” property

  “format”                   GstMpeg2encFormat

Encoding profile format.

Flags: Read / Write

Default value: Generic MPEG-1

The “framerate” property

  “framerate”                GstMpeg2encFramerate

Output framerate.

Flags: Read / Write

Default value: Same as input

The “interlace-mode” property

  “interlace-mode”           GstMpeg2encInterlaceMode

MPEG-2 motion estimation and encoding modes.

Flags: Read / Write

Default value: Progressive

The “intra-dc-prec” property

  “intra-dc-prec”            gint

Number of bits precision for DC (base colour) in MPEG-2 blocks.

Flags: Read / Write

Allowed values: [8,11]

Default value: 9

The “keep-hf” property

  “keep-hf”                  gboolean

Maximize high-frequency resolution (for high-quality sources).

Flags: Read / Write

Default value: FALSE

The “max-gop-size” property

  “max-gop-size”             gint

Maximal size per Group-of-Pictures (-1=default).

Flags: Read / Write

Allowed values: [G_MAXULONG,250]

Default value: -1

The “min-gop-size” property

  “min-gop-size”             gint

Minimal size per Group-of-Pictures (-1=default).

Flags: Read / Write

Allowed values: [G_MAXULONG,250]

Default value: -1

The “motion-search-radius” property

  “motion-search-radius”     gint

Motion compensation search radius.

Flags: Read / Write

Allowed values: [0,32]

Default value: 16

The “non-video-bitrate” property

  “non-video-bitrate”        gint

Assumed bitrate of non-video for sequence splitting (kbps).

Flags: Read / Write

Allowed values: [0,10000]

Default value: 0

The “norm” property

  “norm”                     GstMpeg2encVideoNorm

Tag output for specific video norm.

Flags: Read / Write

Default value: Unspecified

The “playback-field-order” property

  “playback-field-order”     GstMpeg2encPlaybackFieldOrders

Force specific playback field order.

Flags: Read / Write

Default value: Unspecified

The “pulldown-3-2” property

  “pulldown-3-2”             gboolean

Generate header flags for 3-2 pull down 24fps movies.

Flags: Read / Write

Default value: FALSE

The “quant-matrix” property

  “quant-matrix”             GstMpeg2encQuantisationMatrix

Quantisation matrix to use for encoding.

Flags: Read / Write

Default value: Default

The “quant-reduction-max-var” property

  “quant-reduction-max-var”  gfloat

Maximal luma variance below which quantisation boost is used.

Flags: Read / Write

Allowed values: [0,2500]

Default value: 100

The “quantisation” property

  “quantisation”             gint

Quantisation factor (-1=cbr, 0=default, 1=best, 31=worst).

Flags: Read / Write

Allowed values: [G_MAXULONG,31]

Default value: 0

The “quantisation-reduction” property

  “quantisation-reduction”   gfloat

Max. quantisation reduction for highly active blocks.

Flags: Read / Write

Allowed values: [-4,10]

Default value: 0

The “reduce-hf” property

  “reduce-hf”                gfloat

How much to reduce high-frequency resolution (by increasing quantisation).

Flags: Read / Write

Allowed values: [0,2]

Default value: 0

The “reduction-2x2” property

  “reduction-2x2”            gint

Reduction factor for 2x2 subsampled candidate motion estimates (1=max. quality, 4=max. speed).

Flags: Read / Write

Allowed values: [1,4]

Default value: 3

The “reduction-4x4” property

  “reduction-4x4”            gint

Reduction factor for 4x4 subsampled candidate motion estimates (1=max. quality, 4=max. speed).

Flags: Read / Write

Allowed values: [1,4]

Default value: 2

The “sequence-header-every-gop” property

  “sequence-header-every-gop” gboolean

Include a sequence header in every GOP.

Flags: Read / Write

Default value: FALSE

The “sequence-length” property

  “sequence-length”          gint

Place a sequence boundary after each <num> MB (0=disable).

Flags: Read / Write

Allowed values: [0,10240]

Default value: 0

The “unit-coeff-elim” property

  “unit-coeff-elim”          gint

How agressively small-unit picture blocks should be skipped.

Flags: Read / Write

Allowed values: [-40,40]

Default value: 0

The “vcd-still-size” property

  “vcd-still-size”           gint

Size of VCD stills (in KB).

Flags: Read / Write

Allowed values: [0,512]

Default value: 0