gstpbutilscodecutils

gstpbutilscodecutils — Miscellaneous codec-specific utility functions

Synopsis

#include <gst/pbutils/codec-utils.h>

guint               gst_codec_utils_aac_get_sample_rate_from_index
                                                        (guint sr_idx);
const gchar *       gst_codec_utils_aac_get_profile     (const guint8 *audio_config,
                                                         guint len);
const gchar *       gst_codec_utils_aac_get_level       (const guint8 *audio_config,
                                                         guint len);
gboolean            gst_codec_utils_aac_caps_set_level_and_profile
                                                        (GstCaps *caps,
                                                         const guint8 *audio_config,
                                                         guint len);

const gchar *       gst_codec_utils_h264_get_profile    (const guint8 *sps,
                                                         guint len);
const gchar *       gst_codec_utils_h264_get_level      (const guint8 *sps,
                                                         guint len);
gboolean            gst_codec_utils_h264_caps_set_level_and_profile
                                                        (GstCaps *caps,
                                                         const guint8 *sps,
                                                         guint len);
guint8              gst_codec_utils_h264_get_level_idc  (const gchar *level);

const gchar *       gst_codec_utils_mpeg4video_get_profile
                                                        (const guint8 *vis_obj_seq,
                                                         guint len);
const gchar *       gst_codec_utils_mpeg4video_get_level
                                                        (const guint8 *vis_obj_seq,
                                                         guint len);
gboolean            gst_codec_utils_mpeg4video_caps_set_level_and_profile
                                                        (GstCaps *caps,
                                                         const guint8 *vis_obj_seq,
                                                         guint len);

Description

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

Details

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.

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_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.

Note

HE-AAC support has not yet been implemented.

audio_config :

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

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

Note

HE-AAC support has not yet been implemented.

audio_config :

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

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_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.

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 a more details).

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

sps :

Pointer to the sequence parameter set for the stream.

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().

sps :

Pointer to the sequence parameter set for the stream.

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.

caps :

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

sps :

Pointer to the sequence parameter set for the stream.

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

level :

A level string from caps

Returns :

the level_idc or 0 if the level is unknown

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.

vis_obj_seq :

Pointer to the visual object sequence for the stream.

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.

vis_obj_seq :

Pointer to the visual object sequence for the stream.

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.

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.

len :

Length of the data available in sps.

Returns :

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