gstaudiometa

gstaudiometa

Synopsis

#include <gst/audio/gstaudiometa.h>

struct              GstAudioDownmixMeta;
GstAudioDownmixMeta * gst_buffer_add_audio_downmix_meta (GstBuffer *buffer,
                                                         const GstAudioChannelPosition *from_position,
                                                         gint from_channels,
                                                         const GstAudioChannelPosition *to_position,
                                                         gint to_channels,
                                                         const gfloat **matrix);
#define             gst_buffer_get_audio_downmix_meta   (b)
GstAudioDownmixMeta * gst_buffer_get_audio_downmix_meta_for_channels
                                                        (GstBuffer *buffer,
                                                         const GstAudioChannelPosition *to_position,
                                                         gint to_channels);

Description

Details

struct GstAudioDownmixMeta

struct GstAudioDownmixMeta {
  GstMeta      meta;

  GstAudioChannelPosition *from_position;
  GstAudioChannelPosition *to_position;
  gint        from_channels, to_channels;
  gfloat       **matrix;
};

Extra buffer metadata describing audio downmixing matrix. This metadata is attached to audio buffers and contains a matrix to downmix the buffer number of channels to channels.

matrix is an two-dimensional array of to_channels times from_channels coefficients, i.e. the i-th output channels is constructed by multiplicating the input channels with the coefficients in matrix[i] and taking the sum of the results.

GstMeta meta;

parent GstMeta

GstAudioChannelPosition *from_position;

the channel positions of the source

GstAudioChannelPosition *to_position;

the channel positions of the destination

gint from_channels;

the number of channels of the source

gint to_channels;

the number of channels of the destination

gfloat **matrix;

the matrix coefficients.

gst_buffer_add_audio_downmix_meta ()

GstAudioDownmixMeta * gst_buffer_add_audio_downmix_meta (GstBuffer *buffer,
                                                         const GstAudioChannelPosition *from_position,
                                                         gint from_channels,
                                                         const GstAudioChannelPosition *to_position,
                                                         gint to_channels,
                                                         const gfloat **matrix);

Attaches GstAudioDownmixMeta metadata to buffer with the given parameters.

matrix is an two-dimensional array of to_channels times from_channels coefficients, i.e. the i-th output channels is constructed by multiplicating the input channels with the coefficients in matrix[i] and taking the sum of the results.

buffer :

a GstBuffer

from_position :

the channel positions of the source. [array length=from_channels]

from_channels :

The number of channels of the source

to_position :

the channel positions of the destination. [array length=to_channels]

to_channels :

The number of channels of the destination

matrix :

The matrix coefficients.

Returns :

the GstAudioDownmixMeta on buffer.

gst_buffer_get_audio_downmix_meta()

#define gst_buffer_get_audio_downmix_meta(b) ((GstAudioDownmixMeta*)gst_buffer_get_meta((b),GST_AUDIO_DOWNMIX_META_INFO))

gst_buffer_get_audio_downmix_meta_for_channels ()

GstAudioDownmixMeta * gst_buffer_get_audio_downmix_meta_for_channels
                                                        (GstBuffer *buffer,
                                                         const GstAudioChannelPosition *to_position,
                                                         gint to_channels);

Find the GstAudioDownmixMeta on buffer for the given destination channel positions.

buffer :

a GstBuffer

to_position :

the channel positions of the destination. [array length=to_channels]

to_channels :

The number of channels of the destination

Returns :

the GstAudioDownmixMeta on buffer.