mpeg4parser

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

Synopsis

#include <gst/codecparsers/gstmpeg4parser.h>

enum                GstMpeg4StartCode;
enum                GstMpeg4VisualObjectType;
enum                GstMpeg4AspectRatioInfo;
enum                GstMpeg4ParseResult;
enum                GstMpeg4VideoObjectCodingType;
enum                GstMpeg4ChromaFormat;
enum                GstMpeg4VideoObjectLayerShape;
enum                GstMpeg4SpriteEnable;
enum                GstMpeg4Profile;
enum                GstMpeg4Level;
struct              GstMpeg4VisualObjectSequence;
struct              GstMpeg4VisualObject;
struct              GstMpeg4VideoSignalType;
struct              GstMpeg4VideoPlaneShortHdr;
struct              GstMpeg4VideoObjectLayer;
struct              GstMpeg4SpriteTrajectory;
struct              GstMpeg4GroupOfVOP;
struct              GstMpeg4VideoObjectPlane;
struct              GstMpeg4Packet;
struct              GstMpeg4VideoPacketHdr;
GstMpeg4ParseResult gst_mpeg4_parse                     (GstMpeg4Packet *packet,
                                                         gboolean skip_user_data,
                                                         GstMpeg4VideoObjectPlane *vop,
                                                         const guint8 *data,
                                                         guint offset,
                                                         gsize size);
GstMpeg4ParseResult gst_mpeg4_parse_video_object_plane  (GstMpeg4VideoObjectPlane *vop,
                                                         GstMpeg4SpriteTrajectory *sprite_trajectory,
                                                         GstMpeg4VideoObjectLayer *vol,
                                                         const guint8 *data,
                                                         gsize size);
GstMpeg4ParseResult gst_mpeg4_parse_group_of_vop        (GstMpeg4GroupOfVOP *gov,
                                                         const guint8 *data,
                                                         gsize size);
GstMpeg4ParseResult gst_mpeg4_parse_video_object_layer  (GstMpeg4VideoObjectLayer *vol,
                                                         GstMpeg4VisualObject *vo,
                                                         const guint8 *data,
                                                         gsize size);
GstMpeg4ParseResult gst_mpeg4_parse_visual_object       (GstMpeg4VisualObject *vo,
                                                         GstMpeg4VideoSignalType *signal_type,
                                                         const guint8 *data,
                                                         gsize size);
GstMpeg4ParseResult gst_mpeg4_parse_visual_object_sequence
                                                        (GstMpeg4VisualObjectSequence *vos,
                                                         const guint8 *data,
                                                         gsize size);
GstMpeg4ParseResult gst_mpeg4_parse_video_packet_header (GstMpeg4VideoPacketHdr *videopackethdr,
                                                         GstMpeg4VideoObjectLayer *vol,
                                                         GstMpeg4VideoObjectPlane *vop,
                                                         GstMpeg4SpriteTrajectory *sprite_trajectory,
                                                         const guint8 *data,
                                                         gsize size);

Description

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

Details

enum GstMpeg4StartCode

typedef enum {
  GST_MPEG4_VIDEO_OBJ_FIRST      = 0x00,
  GST_MPEG4_VIDEO_OBJ_LAST       = 0x1f,
  GST_MPEG4_VIDEO_LAYER_FIRST    = 0x20,
  GST_MPEG4_VIDEO_LAYER_LAST     = 0x2f,
  GST_MPEG4_VISUAL_OBJ_SEQ_START = 0xb0,
  GST_MPEG4_VISUAL_OBJ_SEQ_END   = 0xb1,
  GST_MPEG4_USER_DATA            = 0xb2,
  GST_MPEG4_GROUP_OF_VOP         = 0xb3,
  GST_MPEG4_VIDEO_SESSION_ERR    = 0xb4,
  GST_MPEG4_VISUAL_OBJ           = 0xb5,
  GST_MPEG4_VIDEO_OBJ_PLANE      = 0xb6,
  GST_MPEG4_FBA                  = 0xba,
  GST_MPEG4_FBA_PLAN             = 0xbb,
  GST_MPEG4_MESH                 = 0xbc,
  GST_MPEG4_MESH_PLAN            = 0xbd,
  GST_MPEG4_STILL_TEXTURE_OBJ    = 0xbe,
  GST_MPEG4_TEXTURE_SPATIAL      = 0xbf,
  GST_MPEG4_TEXTURE_SNR_LAYER    = 0xc0,
  GST_MPEG4_TEXTURE_TILE         = 0xc1,
  GST_MPEG4_SHAPE_LAYER          = 0xc2,
  GST_MPEG4_STUFFING             = 0xc3,
  GST_MPEG4_SYSTEM_FIRST         = 0xc6,
  GST_MPEG4_SYSTEM_LAST          = 0xff,
  GST_MPEG4_RESYNC               = 0xfff
} GstMpeg4StartCode;

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


enum GstMpeg4VisualObjectType

typedef enum {
  GST_MPEG4_VIDEO_ID         = 0x01,
  GST_MPEG4_STILL_TEXTURE_ID = 0x02,
  GST_MPEG4_STILL_MESH_ID    = 0x03,
  GST_MPEG4_STILL_FBA_ID     = 0x04,
  GST_MPEG4_STILL_3D_MESH_ID = 0x05,
  /*... reserved */
} GstMpeg4VisualObjectType;

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


enum GstMpeg4AspectRatioInfo

typedef enum {
  GST_MPEG4_SQUARE        = 0x01,
  GST_MPEG4_625_TYPE_4_3  = 0x02,
  GST_MPEG4_525_TYPE_4_3  = 0x03,
  GST_MPEG4_625_TYPE_16_9 = 0x04,
  GST_MPEG4_525_TYPE_16_9 = 0x05,
  GST_MPEG4_EXTENDED_PAR  = 0x0f,
} GstMpeg4AspectRatioInfo;

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

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

typedef enum {
  GST_MPEG4_PARSER_OK,
  GST_MPEG4_PARSER_BROKEN_DATA,
  GST_MPEG4_PARSER_NO_PACKET,
  GST_MPEG4_PARSER_NO_PACKET_END,
  GST_MPEG4_PARSER_ERROR,
} GstMpeg4ParseResult;

Result type of any parsing function.

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

typedef enum {
  GST_MPEG4_I_VOP = 0x0,
  GST_MPEG4_P_VOP = 0x1,
  GST_MPEG4_B_VOP = 0x2,
  GST_MPEG4_S_VOP = 0x3
} GstMpeg4VideoObjectCodingType;

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

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

typedef enum {
  /* Other value are reserved */
  GST_MPEG4_CHROMA_4_2_0 = 0x01
} GstMpeg4ChromaFormat;

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


enum GstMpeg4VideoObjectLayerShape

typedef enum {
  GST_MPEG4_RECTANGULAR,
  GST_MPEG4_BINARY,
  GST_MPEG4_BINARY_ONLY,
  GST_MPEG4_GRAYSCALE
} GstMpeg4VideoObjectLayerShape;

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


enum GstMpeg4SpriteEnable

typedef enum {
  GST_MPEG4_SPRITE_UNUSED,
  GST_MPEG4_SPRITE_STATIC,
  GST_MPEG4_SPRITE_GMG
} GstMpeg4SpriteEnable;

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


enum GstMpeg4Profile

typedef enum {
  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
} 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


enum GstMpeg4Level

typedef enum {
  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
} GstMpeg4Level;

Different levels as defined in: 9- Profiles and levels

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


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;
};

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

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

guint8 header_extension_code;

guint16 macroblock_number;

guint16 quant_scale;

guint size;

Size of the header in bit.

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.

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

Returns :

a GstMpeg4ParseResult

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.

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

Returns :

a GstMpeg4ParseResult

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.

gov :

The GstMpeg4GroupOfVOP structure to fill

data :

The data to parse

size :

The size of the data to parse

Returns :

a GstMpeg4ParseResult

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.

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

Returns :

a GstMpeg4ParseResult

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.

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

Returns :

a GstMpeg4ParseResult

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.

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

Returns :

a GstMpeg4ParseResult

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

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