ao_plugin_open

declared in "ao/plugin.h";

Open the device for playback. All of the device options will have already been set by previous calls to ao_plugin_set_option(). If this is a file output driver, the file itself will have be already opened and a pointer to a FILE structure stored in device->file.

If the plugin wishes to support automatic channel mapping, but it was not possible to set device->output_matrix in ao_plugin_device_init(), the plugin should now set device->inter_matrix to the channel ordering that will be expected for buffers submitted to ao_plugin_play().

Plugins should use device->output_channels to determine the number of output channels to configure, not format->channels. device->output_channels is the number of channels libao will be submitting upon each call to ao_plugin_play(). A plugin may alter the value of device->output_channels to demand a different number of channels if necessary (such as if a plugin is manufacturing a channel mapping manually).

int ao_plugin_open(ao_device *device, ao_sample_format *format);

Parameters

device

Pointer to pre-allocated device structure. The plugin should set its desired byte format in device->driver_byte_format.

format

Output device sample format. format->byte_format should be ignored as it is relevant only to the library core. format->channels is relevant only if a plugin is constructing a channel mapping manually; otherwise device->output should be used as it is the actual number of channels that will be sent to ao_plugin_play().

Return Values

1 indicates success.

0 indicates failure to open the device. ao_plugin_device_clear() should be called to ensure the deallocate of all private data structures.