mpeg4parser

mpeg4parser — Convenience library for parsing mpeg4 part 2 video bitstream.

Functions

Types and Values

Object Hierarchy


Includes

#include <gst/codecparsers/gstmpeg4parser.h>

Description

For more details about the structures, you can refer to the specifications: ISO-IEC-14496-2_2004_MPEG4_VISUAL.pdf

Functions

gst_mpeg4_parse ()

GstMpeg4ParseResult
gst_mpeg4_parse (GstMpeg4Packet *packet,
                 gboolean skip_user_data,
                 GstMpeg4VideoObjectPlane *vop,
                 const guint8 *data,
                 guint offset,
                 gsize size);

Parses data and fills packet with the information of the next packet found.

Parameters

packet

The GstMpeg4Packet to fill

 

skip_user_data

TRUE to skip user data packet FALSE otherwize

 

vop

The last parsed GstMpeg4VideoObjectPlane or NULL if you do not need to detect the resync codes.

 

offset

offset from which to start the parsing

 

data

The data to parse

 

size

The size of the data to parse

 

gst_mpeg4_parse_video_object_plane ()

GstMpeg4ParseResult
gst_mpeg4_parse_video_object_plane (GstMpeg4VideoObjectPlane *vop,
                                    GstMpeg4SpriteTrajectory *sprite_trajectory,
                                    GstMpeg4VideoObjectLayer *vol,
                                    const guint8 *data,
                                    gsize size);

Parses data containing the video object plane packet, and fills the vol structure.

Parameters

vop

The GstMpeg4VideoObjectPlane currently being parsed

 

sprite_trajectory

A GstMpeg4SpriteTrajectory to fill or NULL

 

vol

The GstMpeg4VideoObjectLayer structure to fill

 

data

The data to parse

 

size

The size of the data to parse

 

gst_mpeg4_parse_group_of_vop ()

GstMpeg4ParseResult
gst_mpeg4_parse_group_of_vop (GstMpeg4GroupOfVOP *gov,
                              const guint8 *data,
                              gsize size);

Parses data containing the group of video object plane packet, and fills the gov structure.

Parameters

gov

The GstMpeg4GroupOfVOP structure to fill

 

data

The data to parse

 

size

The size of the data to parse

 

gst_mpeg4_parse_video_object_layer ()

GstMpeg4ParseResult
gst_mpeg4_parse_video_object_layer (GstMpeg4VideoObjectLayer *vol,
                                    GstMpeg4VisualObject *vo,
                                    const guint8 *data,
                                    gsize size);

Parses data containing the video object layer packet, and fills the vol structure.

Parameters

vol

The GstMpeg4VideoObjectLayer structure to fill

 

vo

The GstMpeg4VisualObject currently being parsed or NULL

 

data

The data to parse

 

size

The size of the data to parse

 

gst_mpeg4_parse_visual_object ()

GstMpeg4ParseResult
gst_mpeg4_parse_visual_object (GstMpeg4VisualObject *vo,
                               GstMpeg4VideoSignalType *signal_type,
                               const guint8 *data,
                               gsize size);

Parses data containing the visual object packet, and fills the vo structure.

Parameters

vo

The GstMpeg4VisualObject structure to fill

 

signal_type

The GstMpeg4VideoSignalType to fill or NULL

 

data

The data to parse, should contain the vo_start_code but not the start code prefix

 

size

The size of the data to parse

 

gst_mpeg4_parse_visual_object_sequence ()

GstMpeg4ParseResult
gst_mpeg4_parse_visual_object_sequence
                               (GstMpeg4VisualObjectSequence *vos,
                                const guint8 *data,
                                gsize size);

Parses data containing the visual object sequence packet, and fills the vos structure.

Parameters

vos

The GstMpeg4VisualObjectSequence structure to fill

 

data

The data to parse, should contain the visual_object_sequence_start_code but not the start code prefix

 

size

The size of the data to parse

 

gst_mpeg4_parse_video_packet_header ()

GstMpeg4ParseResult
gst_mpeg4_parse_video_packet_header (GstMpeg4VideoPacketHdr *videopackethdr,
                                     GstMpeg4VideoObjectLayer *vol,
                                     GstMpeg4VideoObjectPlane *vop,
                                     GstMpeg4SpriteTrajectory *sprite_trajectory,
                                     const guint8 *data,
                                     gsize size);

Parsers data containing the video packet header and fills the videopackethdr structure

Parameters

videopackethdr

The GstMpeg4VideoPacketHdr structure to fill

 

vol

The last parsed GstMpeg4VideoObjectLayer, will be updated with the informations found during the parsing

 

vop

The last parsed GstMpeg4VideoObjectPlane, will be updated with the informations found during the parsing

 

sprite_trajectory

A GstMpeg4SpriteTrajectory to fill or NULL with the informations found during the parsing

 

data

The data to parse, should be set after the resync marker.

 

size

The size of the data to parse

 

Types and Values

enum GstMpeg4StartCode

Defines the different startcodes present in the bitstream as defined in: Table 6-3 — Start code values

Members

GST_MPEG4_VIDEO_OBJ_FIRST

   

GST_MPEG4_VIDEO_OBJ_LAST

   

GST_MPEG4_VIDEO_LAYER_FIRST

   

GST_MPEG4_VIDEO_LAYER_LAST

   

GST_MPEG4_VISUAL_OBJ_SEQ_START

   

GST_MPEG4_VISUAL_OBJ_SEQ_END

   

GST_MPEG4_USER_DATA

   

GST_MPEG4_GROUP_OF_VOP

   

GST_MPEG4_VIDEO_SESSION_ERR

   

GST_MPEG4_VISUAL_OBJ

   

GST_MPEG4_VIDEO_OBJ_PLANE

   

GST_MPEG4_FBA

   

GST_MPEG4_FBA_PLAN

   

GST_MPEG4_MESH

   

GST_MPEG4_MESH_PLAN

   

GST_MPEG4_STILL_TEXTURE_OBJ

   

GST_MPEG4_TEXTURE_SPATIAL

   

GST_MPEG4_TEXTURE_SNR_LAYER

   

GST_MPEG4_TEXTURE_TILE

   

GST_MPEG4_SHAPE_LAYER

   

GST_MPEG4_STUFFING

   

GST_MPEG4_SYSTEM_FIRST

   

GST_MPEG4_SYSTEM_LAST

   

GST_MPEG4_RESYNC

   

enum GstMpeg4VisualObjectType

Defines the different visual object types as defined in: Table 6-5 -- Meaning of visual object type

Members

GST_MPEG4_VIDEO_ID

   

GST_MPEG4_STILL_TEXTURE_ID

   

GST_MPEG4_STILL_MESH_ID

   

GST_MPEG4_STILL_FBA_ID

   

GST_MPEG4_STILL_3D_MESH_ID

   

enum GstMpeg4AspectRatioInfo

Defines the different pixel aspect ratios as defined in: Table 6-12 -- Meaning of pixel aspect ratio

Members

GST_MPEG4_SQUARE

1:1 square

 

GST_MPEG4_625_TYPE_4_3

12:11 (625-type for 4:3 picture)

 

GST_MPEG4_525_TYPE_4_3

10:11 (525-type for 4:3 picture)

 

GST_MPEG4_625_TYPE_16_9

16:11 (625-type stretched for 16:9 picture)

 

GST_MPEG4_525_TYPE_16_9

40:33 (525-type stretched for 16:9 picture)

 

GST_MPEG4_EXTENDED_PAR

Extended par

 

enum GstMpeg4ParseResult

Result type of any parsing function.

Members

GST_MPEG4_PARSER_OK

The parsing went well

 

GST_MPEG4_PARSER_BROKEN_DATA

The bitstream was broken

 

GST_MPEG4_PARSER_NO_PACKET

There was no packet in the buffer

 

GST_MPEG4_PARSER_NO_PACKET_END

There was no packet end in the buffer

 

GST_MPEG4_PARSER_ERROR

   

enum GstMpeg4VideoObjectCodingType

The vop coding types as defined in: Table 6-20 -- Meaning of vop_coding_type

Members

GST_MPEG4_I_VOP

intra-coded (I)

 

GST_MPEG4_P_VOP

predictive-coded (P)

 

GST_MPEG4_B_VOP

bidirectionally-predictive-coded (B)

 

GST_MPEG4_S_VOP

sprite (S)

 

enum GstMpeg4ChromaFormat

The chroma format in use as defined in: Table 6-13 -- Meaning of chroma_format

Members

GST_MPEG4_CHROMA_4_2_0

   

enum GstMpeg4VideoObjectLayerShape

The different video object layer shapes as defined in: Table 6-16 — Video Object Layer shape type

Members

GST_MPEG4_RECTANGULAR

   

GST_MPEG4_BINARY

   

GST_MPEG4_BINARY_ONLY

   

GST_MPEG4_GRAYSCALE

   

enum GstMpeg4SpriteEnable

Indicates the usage of static sprite coding or global motion compensation (GMC) as defined in: Table V2 - 2 -- Meaning of sprite_enable codewords

Members

GST_MPEG4_SPRITE_UNUSED

   

GST_MPEG4_SPRITE_STATIC

   

GST_MPEG4_SPRITE_GMG

   

enum GstMpeg4Profile

Different defined profiles as defined in: 9- Profiles and levels

It is computed using: Table G.1 — FLC table for profile_and_level_indication

Members

GST_MPEG4_PROFILE_CORE

   

GST_MPEG4_PROFILE_MAIN

   

GST_MPEG4_PROFILE_N_BIT

   

GST_MPEG4_PROFILE_SIMPLE

   

GST_MPEG4_PROFILE_HYBRID

   

GST_MPEG4_PROFILE_RESERVED

   

GST_MPEG4_PROFILE_SIMPLE_FBA

   

GST_MPEG4_PROFILE_CORE_STUDIO

   

GST_MPEG4_PROFILE_SIMPLE_STUDIO

   

GST_MPEG4_PROFILE_CORE_SCALABLE

   

GST_MPEG4_PROFILE_ADVANCED_CORE

   

GST_MPEG4_PROFILE_ADVANCED_SIMPLE

   

GST_MPEG4_PROFILE_SIMPLE_SCALABLE

   

GST_MPEG4_PROFILE_SCALABLE_TEXTURE

   

GST_MPEG4_PROFILE_SIMPLE_FACE_ANIMATION

   

GST_MPEG4_PROFILE_BASIC_ANIMATED_TEXTURE

   

GST_MPEG4_PROFILE_ADVANCED_REALTIME_SIMPLE

   

GST_MPEG4_PROFILE_ADVANCED_SCALABLE_TEXTURE

   

GST_MPEG4_PROFILE_FINE_GRANULARITY_SCALABLE

   

GST_MPEG4_PROFILE_ADVANCED_CODING_EFFICIENCY

   

enum GstMpeg4Level

Different levels as defined in: 9- Profiles and levels

It is computed using: Table G.1 — FLC table for profile_and_level_indication

Members

GST_MPEG4_LEVEL0

   

GST_MPEG4_LEVEL1

   

GST_MPEG4_LEVEL2

   

GST_MPEG4_LEVEL3

   

GST_MPEG4_LEVEL3b

   

GST_MPEG4_LEVEL4

   

GST_MPEG4_LEVEL5

   

GST_MPEG4_LEVEL_RESERVED

   

struct GstMpeg4VisualObjectSequence

struct GstMpeg4VisualObjectSequence {
  guint8 profile_and_level_indication;

  /* Computed according to:
   * Table G.1 — FLC table for profile_and_level_indication */
  GstMpeg4Level level;
  GstMpeg4Profile profile;
};

The visual object sequence structure as defined in: 6.2.2 Visual Object Sequence and Visual Object


struct GstMpeg4VisualObject

struct GstMpeg4VisualObject {
  guint8 is_identifier;
  /* If is_identifier */
  guint8 verid;
  guint8 priority;

  GstMpeg4VisualObjectType type;
};

The visual object structure as defined in: 6.2.2 Visual Object Sequence and Visual Object


struct GstMpeg4VideoSignalType

struct GstMpeg4VideoSignalType {
  guint8 type;

  guint8 format;
  guint8 range;
  guint8 color_description;
  guint8 color_primaries;
  guint8 transfer_characteristics;
  guint8 matrix_coefficients;
};

The video signal type structure as defined in: 6.2.2 Visual Object Sequence and Visual Object.


struct GstMpeg4VideoPlaneShortHdr

struct GstMpeg4VideoPlaneShortHdr {
  guint8 temporal_reference;
  guint8 split_screen_indicator;
  guint8 document_camera_indicator;
  guint8 full_picture_freeze_release;
  guint8 source_format;
  guint8 picture_coding_type;
  guint8 vop_quant;
  guint8 pei;
  guint8 psupp;

  /*  Gob layer specific fields */
  guint8 gob_header_empty;
  guint8 gob_number;
  guint8 gob_frame_id;
  guint8 quant_scale;

  /* Computed
   * If all the values are set to 0, then it is reserved
   * Table 6-25 -- Parameters Defined by source_format Field
   */
  guint16 vop_width;
  guint16 vop_height;
  guint16 num_macroblocks_in_gob;
  guint8 num_gobs_in_vop;

  /* The size in bits */
  guint size;
};

The video plane short header structure as defined in: 6.2.5.2 Video Plane with Short Header


struct GstMpeg4VideoObjectLayer

struct GstMpeg4VideoObjectLayer {
  guint8 random_accessible_vol;
  guint8 video_object_type_indication;

  guint8 is_object_layer_identifier;
  /* if is_object_layer_identifier */
  guint8 verid;
  guint8 priority;

  GstMpeg4AspectRatioInfo aspect_ratio_info;
  guint8 par_width;
  guint8 par_height;

  guint8 control_parameters;
  /* if control_parameters */
  GstMpeg4ChromaFormat chroma_format;
  guint8 low_delay;
  guint8 vbv_parameters;
  /* if vbv_parameters */
  guint16 first_half_bitrate;
  guint16 latter_half_bitrate;
  guint16 first_half_vbv_buffer_size;
  guint16 latter_half_vbv_buffer_size;
  guint16 first_half_vbv_occupancy;
  guint16 latter_half_vbv_occupancy;

  /* Computed values */
  guint32 bit_rate;
  guint32 vbv_buffer_size;

  GstMpeg4VideoObjectLayerShape shape;
  /* if shape == GST_MPEG4_GRAYSCALE && verid =! 1 */
  guint8 shape_extension;

  guint16 vop_time_increment_resolution;
  guint8 vop_time_increment_bits;
  guint8 fixed_vop_rate;
  /* if fixed_vop_rate */
  guint16 fixed_vop_time_increment;

  guint16 width;
  guint16 height;
  guint8 interlaced;
  guint8 obmc_disable;

  GstMpeg4SpriteEnable sprite_enable;
  /* if vol->sprite_enable == SPRITE_GMG or SPRITE_STATIC*/
  /* if vol->sprite_enable != GST_MPEG4_SPRITE_GMG */
  guint16 sprite_width;
  guint16 sprite_height;
  guint16 sprite_left_coordinate;
  guint16 sprite_top_coordinate;

  guint8 no_of_sprite_warping_points;
  guint8 sprite_warping_accuracy;
  guint8 sprite_brightness_change;
  /* if vol->sprite_enable != GST_MPEG4_SPRITE_GMG */
  guint8 low_latency_sprite_enable;

  /* if shape != GST_MPEG4_RECTANGULAR */
  guint8 sadct_disable;

  guint8 not_8_bit;

  /* if no_8_bit */
  guint8 quant_precision;
  guint8 bits_per_pixel;

  /* if shape == GRAYSCALE */
  guint8 no_gray_quant_update;
  guint8 composition_method;
  guint8 linear_composition;

  guint8 quant_type;
  /* if quant_type */
  guint8 load_intra_quant_mat;
  guint8 intra_quant_mat[64];
  guint8 load_non_intra_quant_mat;
  guint8 non_intra_quant_mat[64];

  guint8 quarter_sample;
  guint8 complexity_estimation_disable;
  guint8 resync_marker_disable;
  guint8 data_partitioned;
  guint8 reversible_vlc;
  guint8 newpred_enable;
  guint8 reduced_resolution_vop_enable;
  guint8 scalability;
  guint8 enhancement_type;

  GstMpeg4VideoPlaneShortHdr short_hdr;
};

The video object layer structure as defined in: 6.2.3 Video Object Layer


struct GstMpeg4SpriteTrajectory

struct GstMpeg4SpriteTrajectory {
  guint16 vop_ref_points[63]; /* Defined as "du" in 6.2.5.4 */
  guint16 sprite_ref_points[63]; /* Defined as "dv" in 6.2.5.4 */
};

The sprite trajectory structure as defined in: 7.8.4 Sprite reference point decoding and 6.2.5.4 Sprite coding


struct GstMpeg4GroupOfVOP

struct GstMpeg4GroupOfVOP {
  guint8 hours;
  guint8 minutes;
  guint8 seconds;

  guint8 closed;
  guint8 broken_link;
};

The group of video object plane structure as defined in: 6.2.4 Group of Video Object Plane


struct GstMpeg4VideoObjectPlane

struct GstMpeg4VideoObjectPlane {
  GstMpeg4VideoObjectCodingType coding_type;

  guint8  modulo_time_base;
  guint16 time_increment;

  guint8  coded;
  /* if newpred_enable */
  guint16 id;
  guint8  id_for_prediction_indication;
  guint16 id_for_prediction;

  guint16 width;
  guint16 height;
  guint16 horizontal_mc_spatial_ref;
  guint16 vertical_mc_spatial_ref;

  guint8  rounding_type;
  /*if vol->shape != GST_MPEG4_RECTANGULAR */
  guint8  background_composition;
  guint8  change_conv_ratio_disable;
  guint8  constant_alpha;
  guint8  constant_alpha_value;
  guint8  reduced_resolution;

  guint8  intra_dc_vlc_thr;


  guint8  top_field_first;
  guint8  alternate_vertical_scan_flag;

  guint16 quant;

  guint8  fcode_forward;
  guint8  fcode_backward;

  guint8  shape_coding_type;
  guint8  load_backward_shape;
  guint8  ref_select_code;

  /* Computed macroblock informations */
  guint16 mb_height;
  guint16 mb_width;
  guint mb_num;

  /* The size of the header */
  guint    size;
};

The Video object plane structure as defined in: 6.2.5 Video Object Plane and Video Plane with Short Header


struct GstMpeg4Packet

struct GstMpeg4Packet {
  const guint8     *data;
  guint             offset;
  gsize             size;
  guint             marker_size;

  GstMpeg4StartCode type;
};

A structure that contains the type of a packet, its offset and its size

Members

const guint8 *data;

the data containing packet starting at offset

 

guint offset;

offset of the start of the packet (without the 3 bytes startcode), but including the GstMpeg4StartCode byte.

 

gsize size;

The size in bytes of the packet or G_MAXUINT if the end wasn't found.

 

guint marker_size;

The size in bit of the resync marker.

 

GstMpeg4StartCode type;

the type of the packet that start at offset

 

struct GstMpeg4VideoPacketHdr

struct GstMpeg4VideoPacketHdr {
  guint8  header_extension_code;
  guint16 macroblock_number;
  guint16 quant_scale;
  guint   size;
};

The video packet header structure as defined in: 6.2.5.2 Video Plane with Short Header

Members

guint8 header_extension_code;

   

guint16 macroblock_number;

   

guint16 quant_scale;

   

guint size;

Size of the header in bit.