GST_AUDIO_CHANNEL_POSITION_MASK()

#define GST_AUDIO_CHANNEL_POSITION_MASK(pos) (G_GUINT64_CONSTANT(1)<< GST_AUDIO_CHANNEL_POSITION_ ## pos)

gst_audio_channel_positions_to_mask ()

gboolean
gst_audio_channel_positions_to_mask (const GstAudioChannelPosition *position,
                                     gint channels,
                                     gboolean force_order,
                                     guint64 *channel_mask);

Convert the position array of channels channels to a bitmask.

If force_order is TRUE it additionally checks if the channels are in the order required by GStreamer.

gst_audio_channel_positions_from_mask ()

gboolean
gst_audio_channel_positions_from_mask (gint channels,
                                       guint64 channel_mask,
                                       GstAudioChannelPosition *position);

Convert the channels present in channel_mask to a position array (which should have at least channels entries ensured by caller). If channel_mask is set to 0, it is considered as 'not present' for purpose of conversion. A partially valid channel_mask with less bits set than the number of channels is considered valid.

gst_audio_channel_positions_to_valid_order ()

gboolean
gst_audio_channel_positions_to_valid_order
                               (GstAudioChannelPosition *position,
                                gint channels);

Reorders the channel positions in position from any order to the GStreamer channel order.

gst_audio_channel_get_fallback_mask ()

guint64
gst_audio_channel_get_fallback_mask (gint channels);

Get the fallback channel-mask for the given number of channels.

This function returns a reasonable fallback channel-mask and should be called as a last resort when the specific channel map is unknown.

Since: 1.8

gst_audio_check_valid_channel_positions ()

gboolean
gst_audio_check_valid_channel_positions
                               (const GstAudioChannelPosition *position,
                                gint channels,
                                gboolean force_order);

Checks if position contains valid channel positions for channels channels. If force_order is TRUE it additionally checks if the channels are in the order required by GStreamer.

gst_audio_buffer_reorder_channels ()

gboolean
gst_audio_buffer_reorder_channels (GstBuffer *buffer,
                                   GstAudioFormat format,
                                   gint channels,
                                   const GstAudioChannelPosition *from,
                                   const GstAudioChannelPosition *to);

Reorders buffer from the channel positions from to the channel positions to . from and to must contain the same number of positions and the same positions, only in a different order. buffer must be writable.

gst_audio_reorder_channels ()

gboolean
gst_audio_reorder_channels (gpointer data,
                            gsize size,
                            GstAudioFormat format,
                            gint channels,
                            const GstAudioChannelPosition *from,
                            const GstAudioChannelPosition *to);

Reorders data from the channel positions from to the channel positions to . from and to must contain the same number of positions and the same positions, only in a different order.

gst_audio_get_channel_reorder_map ()

gboolean
gst_audio_get_channel_reorder_map (gint channels,
                                   const GstAudioChannelPosition *from,
                                   const GstAudioChannelPosition *to,
                                   gint *reorder_map);

Returns a reorder map for from to to that can be used in custom channel reordering code, e.g. to convert from or to the GStreamer channel order. from and to must contain the same number of positions and the same positions, only in a different order.

The resulting reorder_map can be used for reordering by assigning channel i of the input to channel reorder_map[i] of the output.

gst_audio_channel_positions_to_string ()

gchar *
gst_audio_channel_positions_to_string (const GstAudioChannelPosition *position,
                                       gint channels);

Converts position to a human-readable string representation for debugging purposes.

gst_audio_channel_mixer_new ()

GstAudioChannelMixer *
gst_audio_channel_mixer_new (GstAudioChannelMixerFlags flags,
                             GstAudioFormat format,
                             gint in_channels,
                             GstAudioChannelPosition *in_position,
                             gint out_channels,
                             GstAudioChannelPosition *out_position);

gst_audio_channel_mixer_new_with_matrix ()

GstAudioChannelMixer *
gst_audio_channel_mixer_new_with_matrix
                               (GstAudioChannelMixerFlags flags,
                                GstAudioFormat format,
                                gint in_channels,
                                gint out_channels,
                                gfloat **matrix);

gst_audio_channel_mixer_free ()

void
gst_audio_channel_mixer_free (GstAudioChannelMixer *mix);

Free memory allocated by mix .

gst_audio_channel_mixer_is_passthrough ()

gboolean
gst_audio_channel_mixer_is_passthrough
                               (GstAudioChannelMixer *mix);

Check if mix is in passthrough.

Only N x N mix identity matrices are considered passthrough, this is determined by comparing the contents of the matrix with 0.0 and 1.0.

As this is floating point comparisons, if the values have been generated, they should be rounded up or down by explicit assignment of 0.0 or 1.0 to values within a user-defined epsilon, this code doesn't make assumptions as to what may constitute an appropriate epsilon.

gst_audio_channel_mixer_samples ()

void
gst_audio_channel_mixer_samples (GstAudioChannelMixer *mix,
                                 const gpointer in[],
                                 gpointer out[],
                                 gint samples);

In case the samples are interleaved, in and out must point to an array with a single element pointing to a block of interleaved samples.

If non-interleaved samples are used, in and out must point to an array with pointers to memory blocks, one for each channel.

Perform channel mixing on in_data and write the result to out_data . in_data and out_data need to be in format and layout .

enum GstAudioChannelPosition

Audio channel positions.

These are the channels defined in SMPTE 2036-2-2008 Table 1 for 22.2 audio systems with the Surround and Wide channels from DTS Coherent Acoustics (v.1.3.1) and 10.2 and 7.1 layouts. In the caps the actual channel layout is expressed with a channel count and a channel mask, which describes the existing channels. The positions in the bit mask correspond to the enum values. For negotiation it is allowed to have more bits set in the channel mask than the number of channels to specify the allowed channel positions but this is not allowed in negotiated caps. It is not allowed in any situation other than the one mentioned below to have less bits set in the channel mask than the number of channels.

GST_AUDIO_CHANNEL_POSITION_MONO can only be used with a single mono channel that has no direction information and would be mixed into all directional channels. This is expressed in caps by having a single channel and no channel mask.

GST_AUDIO_CHANNEL_POSITION_NONE can only be used if all channels have this position. This is expressed in caps by having a channel mask with no bits set.

As another special case it is allowed to have two channels without a channel mask. This implicitely means that this is a stereo stream with a front left and front right channel.

GstAudioChannelMixer

typedef struct _GstAudioChannelMixer GstAudioChannelMixer;

enum GstAudioChannelMixerFlags

Flags passed to gst_audio_channel_mixer_new()