Codec utilities

Codec utilities — Miscellaneous codec-specific utility functions

Functions

Includes

#include <gst/pbutils/pbutils.h>

Description

Provides codec-specific ulility functions such as functions to provide the codec profile and level in human-readable string form from header data.

Functions

gst_codec_utils_aac_get_sample_rate_from_index ()

guint
gst_codec_utils_aac_get_sample_rate_from_index
                               (guint sr_idx);

Translates the sample rate index found in AAC headers to the actual sample rate.

Parameters

sr_idx

Sample rate index as from the AudioSpecificConfig (MPEG-4 container) or ADTS frame header

 

Returns

The sample rate if sr_idx is valid, 0 otherwise.


gst_codec_utils_aac_get_index_from_sample_rate ()

gint
gst_codec_utils_aac_get_index_from_sample_rate
                               (guint rate);

Translates the sample rate to the index corresponding to it in AAC spec.

Parameters

rate

Sample rate

 

Returns

The AAC index for this sample rate, -1 if the rate is not a valid AAC sample rate.


gst_codec_utils_aac_get_profile ()

const gchar *
gst_codec_utils_aac_get_profile (const guint8 *audio_config,
                                 guint len);

Returns the profile of the given AAC stream as a string. The profile is determined using the AudioObjectType field which is in the first 5 bits of audio_config .

HE-AAC support has not yet been implemented.

Parameters

audio_config

a pointer to the AudioSpecificConfig as specified in the Elementary Stream Descriptor (esds) in ISO/IEC 14496-1.

[array length=len]

len

Length of audio_config in bytes

 

Returns

The profile as a const string and NULL if the profile could not be determined.


gst_codec_utils_aac_get_level ()

const gchar *
gst_codec_utils_aac_get_level (const guint8 *audio_config,
                               guint len);

Determines the level of a stream as defined in ISO/IEC 14496-3. For AAC LC streams, the constraints from the AAC audio profile are applied. For AAC Main, LTP, SSR and others, the Main profile is used.

The audio_config parameter follows the following format, starting from the most significant bit of the first byte:

  • Bit 0:4 contains the AudioObjectType

  • Bit 5:8 contains the sample frequency index (if this is 0xf, then the next 24 bits define the actual sample frequency, and subsequent fields are appropriately shifted).

  • Bit 9:12 contains the channel configuration

HE-AAC support has not yet been implemented.

Parameters

audio_config

a pointer to the AudioSpecificConfig as specified in the Elementary Stream Descriptor (esds) in ISO/IEC 14496-1.

[array length=len]

len

Length of audio_config in bytes

 

Returns

The level as a const string and NULL if the level could not be determined.


gst_codec_utils_aac_get_channels ()

guint
gst_codec_utils_aac_get_channels (const guint8 *audio_config,
                                  guint len);

Returns the channels of the given AAC stream.

Parameters

audio_config

a pointer to the AudioSpecificConfig as specified in the Elementary Stream Descriptor (esds) in ISO/IEC 14496-1.

[array length=len]

len

Length of audio_config in bytes

 

Returns

The channels or 0 if the channel could not be determined.

Since 1.10


gst_codec_utils_aac_get_sample_rate ()

guint
gst_codec_utils_aac_get_sample_rate (const guint8 *audio_config,
                                     guint len);

Translates the sample rate index found in AAC headers to the actual sample rate.

Parameters

audio_config

a pointer to the AudioSpecificConfig as specified in the Elementary Stream Descriptor (esds) in ISO/IEC 14496-1.

[array length=len]

len

Length of audio_config

 

Returns

The sample rate if sr_idx is valid, 0 otherwise.

Since 1.10


gst_codec_utils_aac_caps_set_level_and_profile ()

gboolean
gst_codec_utils_aac_caps_set_level_and_profile
                               (GstCaps *caps,
                                const guint8 *audio_config,
                                guint len);

Sets the level and profile on caps if it can be determined from audio_config . See gst_codec_utils_aac_get_level() and gst_codec_utils_aac_get_profile() for more details on the parameters. caps must be audio/mpeg caps with an "mpegversion" field of either 2 or 4. If mpegversion is 4, the "base-profile" field is also set in caps .

Parameters

caps

the GstCaps to which level and profile fields are to be added

 

audio_config

a pointer to the AudioSpecificConfig as specified in the Elementary Stream Descriptor (esds) in ISO/IEC 14496-1. (See below for more details).

[array length=len]

len

Length of audio_config in bytes

 

Returns

TRUE if the level and profile could be set, FALSE otherwise.


gst_codec_utils_h264_get_profile ()

const gchar *
gst_codec_utils_h264_get_profile (const guint8 *sps,
                                  guint len);

Converts the profile indication (profile_idc) in the stream's sequence parameter set into a string. The SPS is expected to have the following format, as defined in the H.264 specification. The SPS is viewed as a bitstream here, with bit 0 being the most significant bit of the first byte.

  • Bit 0:7 - Profile indication

  • Bit 8 - constraint_set0_flag

  • Bit 9 - constraint_set1_flag

  • Bit 10 - constraint_set2_flag

  • Bit 11 - constraint_set3_flag

  • Bit 12 - constraint_set3_flag

  • Bit 13:15 - Reserved

  • Bit 16:24 - Level indication

Parameters

sps

Pointer to the sequence parameter set for the stream.

[array length=len]

len

Length of the data available in sps .

 

Returns

The profile as a const string, or NULL if there is an error.


gst_codec_utils_h264_get_level ()

const gchar *
gst_codec_utils_h264_get_level (const guint8 *sps,
                                guint len);

Converts the level indication (level_idc) in the stream's sequence parameter set into a string. The SPS is expected to have the same format as for gst_codec_utils_h264_get_profile().

Parameters

sps

Pointer to the sequence parameter set for the stream.

[array length=len]

len

Length of the data available in sps .

 

Returns

The level as a const string, or NULL if there is an error.


gst_codec_utils_h264_caps_set_level_and_profile ()

gboolean
gst_codec_utils_h264_caps_set_level_and_profile
                               (GstCaps *caps,
                                const guint8 *sps,
                                guint len);

Sets the level and profile in caps if it can be determined from sps . See gst_codec_utils_h264_get_level() and gst_codec_utils_h264_get_profile() for more details on the parameters.

Parameters

caps

the GstCaps to which the level and profile are to be added

 

sps

Pointer to the sequence parameter set for the stream.

[array length=len]

len

Length of the data available in sps .

 

Returns

TRUE if the level and profile could be set, FALSE otherwise.


gst_codec_utils_h264_get_level_idc ()

guint8
gst_codec_utils_h264_get_level_idc (const gchar *level);

Transform a level string from the caps into the level_idc

Parameters

level

A level string from caps

 

Returns

the level_idc or 0 if the level is unknown


gst_codec_utils_h265_get_profile ()

const gchar *
gst_codec_utils_h265_get_profile (const guint8 *profile_tier_level,
                                  guint len);

Converts the profile indication (general_profile_idc) in the stream's profile_level_tier structure into a string. The profile_tier_level is expected to have the following format, as defined in the H.265 specification. The profile_tier_level is viewed as a bitstream here, with bit 0 being the most significant bit of the first byte.

  • Bit 0:1 - general_profile_space

  • Bit 2 - general_tier_flag

  • Bit 3:7 - general_profile_idc

  • Bit 8:39 - gernal_profile_compatibility_flags

  • Bit 40 - general_progressive_source_flag

  • Bit 41 - general_interlaced_source_flag

  • Bit 42 - general_non_packed_constraint_flag

  • Bit 43 - general_frame_only_constraint_flag

  • Bit 44:87 - general_reserved_zero_44bits

  • Bit 88:95 - general_level_idc

Parameters

profile_tier_level

Pointer to the profile_tier_level structure for the stream.

[array length=len]

len

Length of the data available in profile_tier_level

 

Returns

The profile as a const string, or NULL if there is an error.

Since 1.4


gst_codec_utils_h265_get_tier ()

const gchar *
gst_codec_utils_h265_get_tier (const guint8 *profile_tier_level,
                               guint len);

Converts the tier indication (general_tier_flag) in the stream's profile_tier_level structure into a string. The profile_tier_level is expected to have the same format as for gst_codec_utils_h264_get_profile().

Parameters

profile_tier_level

Pointer to the profile_tier_level for the stream.

[array length=len]

len

Length of the data available in profile_tier_level .

 

Returns

The tier as a const string, or NULL if there is an error.

Since 1.4


gst_codec_utils_h265_get_level ()

const gchar *
gst_codec_utils_h265_get_level (const guint8 *profile_tier_level,
                                guint len);

Converts the level indication (general_level_idc) in the stream's profile_tier_level structure into a string. The profiel_tier_level is expected to have the same format as for gst_codec_utils_h264_get_profile().

Parameters

profile_tier_level

Pointer to the profile_tier_level for the stream.

[array length=len]

len

Length of the data available in profile_tier_level .

 

Returns

The level as a const string, or NULL if there is an error.

Since 1.4


gst_codec_utils_h265_get_level_idc ()

guint8
gst_codec_utils_h265_get_level_idc (const gchar *level);

Transform a level string from the caps into the level_idc

Parameters

level

A level string from caps

 

Returns

the level_idc or 0 if the level is unknown

Since 1.4


gst_codec_utils_h265_caps_set_level_tier_and_profile ()

gboolean
gst_codec_utils_h265_caps_set_level_tier_and_profile
                               (GstCaps *caps,
                                const guint8 *profile_tier_level,
                                guint len);

Sets the level, tier and profile in caps if it can be determined from profile_tier_level . See gst_codec_utils_h265_get_level(), gst_codec_utils_h265_get_tier() and gst_codec_utils_h265_get_profile() for more details on the parameters.

Parameters

caps

the GstCaps to which the level, tier and profile are to be added

 

profile_tier_level

Pointer to the profile_tier_level struct.

[array length=len]

len

Length of the data available in profile_tier_level .

 

Returns

TRUE if the level, tier, profile could be set, FALSE otherwise.

Since 1.4


gst_codec_utils_mpeg4video_get_profile ()

const gchar *
gst_codec_utils_mpeg4video_get_profile
                               (const guint8 *vis_obj_seq,
                                guint len);

Converts the profile indication in the stream's visual object sequence into a string. vis_obj_seq is expected to be the data following the visual object sequence start code. Only the first byte (profile_and_level_indication) is used.

Parameters

vis_obj_seq

Pointer to the visual object sequence for the stream.

[array length=len]

len

Length of the data available in sps .

 

Returns

The profile as a const string, or NULL if there is an error.


gst_codec_utils_mpeg4video_get_level ()

const gchar *
gst_codec_utils_mpeg4video_get_level (const guint8 *vis_obj_seq,
                                      guint len);

Converts the level indication in the stream's visual object sequence into a string. vis_obj_seq is expected to be the data following the visual object sequence start code. Only the first byte (profile_and_level_indication) is used.

Parameters

vis_obj_seq

Pointer to the visual object sequence for the stream.

[array length=len]

len

Length of the data available in sps .

 

Returns

The level as a const string, or NULL if there is an error.


gst_codec_utils_mpeg4video_caps_set_level_and_profile ()

gboolean
gst_codec_utils_mpeg4video_caps_set_level_and_profile
                               (GstCaps *caps,
                                const guint8 *vis_obj_seq,
                                guint len);

Sets the level and profile in caps if it can be determined from vis_obj_seq . See gst_codec_utils_mpeg4video_get_level() and gst_codec_utils_mpeg4video_get_profile() for more details on the parameters.

Parameters

caps

the GstCaps to which the level and profile are to be added

 

vis_obj_seq

Pointer to the visual object sequence for the stream.

[array length=len]

len

Length of the data available in sps .

 

Returns

TRUE if the level and profile could be set, FALSE otherwise.


gst_codec_utils_opus_create_caps ()

GstCaps *
gst_codec_utils_opus_create_caps (guint32 rate,
                                  guint8 channels,
                                  guint8 channel_mapping_family,
                                  guint8 stream_count,
                                  guint8 coupled_count,
                                  const guint8 *channel_mapping);

Creates Opus caps from the given parameters.

Parameters

rate

the sample rate

 

channels

the number of channels

 

channel_mapping_family

the channel mapping family

 

stream_count

the number of independent streams

 

coupled_count

the number of stereo streams

 

channel_mapping

the mapping between the streams.

[allow-none][array]

Returns

The GstCaps, or NULL if the parameters would lead to invalid Opus caps.

Since: 1.8


gst_codec_utils_opus_create_caps_from_header ()

GstCaps *
gst_codec_utils_opus_create_caps_from_header
                               (GstBuffer *header,
                                GstBuffer *comments);

Creates Opus caps from the given OpusHead header and comment header comments .

Parameters

header

OpusHead header

 

comments

Comment header or NULL.

[allow-none]

Returns

The GstCaps.

Since: 1.8


gst_codec_utils_opus_parse_caps ()

gboolean
gst_codec_utils_opus_parse_caps (GstCaps *caps,
                                 guint32 *rate,
                                 guint8 *channels,
                                 guint8 *channel_mapping_family,
                                 guint8 *stream_count,
                                 guint8 *coupled_count,
                                 guint8 channel_mapping[256]);

Parses Opus caps and fills the different fields with defaults if possible.

Parameters

caps

the GstCaps to parse the data from

 

rate

the sample rate.

[out]

channels

the number of channels.

[out]

channel_mapping_family

the channel mapping family.

[out]

stream_count

the number of independent streams.

[out]

coupled_count

the number of stereo streams.

[out]

channel_mapping

the mapping between the streams.

[out][array fixed-size=256]

Returns

TRUE if parsing was successful, FALSE otherwise.

Since: 1.8


gst_codec_utils_opus_create_header ()

GstBuffer *
gst_codec_utils_opus_create_header (guint32 rate,
                                    guint8 channels,
                                    guint8 channel_mapping_family,
                                    guint8 stream_count,
                                    guint8 coupled_count,
                                    const guint8 *channel_mapping,
                                    guint16 pre_skip,
                                    gint16 output_gain);

Creates OpusHead header from the given parameters.

Parameters

rate

the sample rate

 

channels

the number of channels

 

channel_mapping_family

the channel mapping family

 

stream_count

the number of independent streams

 

coupled_count

the number of stereo streams

 

channel_mapping

the mapping between the streams.

[allow-none][array]

pre_skip

Pre-skip in 48kHz samples or 0

 

output_gain

Output gain or 0

 

Returns

The GstBuffer containing the OpusHead.

Since: 1.8


gst_codec_utils_opus_parse_header ()

gboolean
gst_codec_utils_opus_parse_header (GstBuffer *header,
                                   guint32 *rate,
                                   guint8 *channels,
                                   guint8 *channel_mapping_family,
                                   guint8 *stream_count,
                                   guint8 *coupled_count,
                                   guint8 channel_mapping[256],
                                   guint16 *pre_skip,
                                   gint16 *output_gain);

Parses the OpusHead header.

Parameters

header

the OpusHead GstBuffer

 

rate

the sample rate.

[out]

channels

the number of channels.

[out]

channel_mapping_family

the channel mapping family.

[out]

stream_count

the number of independent streams.

[out]

coupled_count

the number of stereo streams.

[out]

channel_mapping

the mapping between the streams.

[out][array fixed-size=256]

pre_skip

Pre-skip in 48kHz samples or 0.

[out]

output_gain

Output gain or 0.

[out]

Returns

TRUE if parsing was successful, FALSE otherwise.

Since: 1.8

Types and Values