/** \brief Consumer abstract service class
*
+ * A consumer is a service that pulls audio and video from the connected
+ * producers, filters, and transitions. Typically a consumer is used to
+ * output audio and/or video to a device, file, or socket.
+ *
* \extends mlt_service_s
+ * \properties \em rescale the scaling algorithm to pass on to all scaling
+ * filters, defaults to "bilinear"
+ * \properties \em buffer the number of frames to use in the asynchronous
+ * render thread, defaults to 25
+ * \properties \em frequency the audio sample rate to use in Hertz, defaults to 48000
+ * \properties \em channels the number of audio channels to use, defaults to 2
+ * \properties \em real_time the asynchronous behavior: 1 (default) for asynchronous
+ * with frame dropping, -1 for asynchronous without frame dropping, 0 to disable (synchronous)
+ * \properties \em test_card the name of a resource to use as the test card, defaults to
+ * environment variable MLT_TEST_CARD. If undefined, the hard-coded default test card is
+ * white silence. A test card is what appears when nothing is produced.
+ * \event \em consumer-frame-show Subclass implementations should fire this.
+ * \event \em consumer-frame-render The abstract class fires this.
+ * \event \em consumer-stopped
+ * \properties \em fps video frames per second as floating point (read only)
+ * \properties \em frame_rate_num the numerator of the video frame rate, overrides \p mlt_profile_s
+ * \properties \em frame_rate_den the denominator of the video frame rate, overrides \p mlt_profile_s
+ * \properties \em width the horizontal video resolution, overrides \p mlt_profile_s
+ * \properties \em height the vertical video resolution, overrides \p mlt_profile_s
+ * \properties \em progressive a flag that indicates if the video is interlaced
+ * or progressive, overrides \p mlt_profile_s
+ * \properties \em aspect_ratio the video sample (pixel) aspect ratio as floating point (read only)
+ * \properties \em sample_aspect_num the numerator of the sample aspect ratio, overrides \p mlt_profile_s
+ * \properties \em sample_aspect_den the denominator of the sample aspect ratio, overrides \p mlt_profile_s
+ * \properties \em display_ratio the video frame aspect ratio as floating point (read only)
+ * \properties \em display_aspect_num the numerator of the video frame aspect ratio, overrides \p mlt_profile_s
+ * \properties \em display_aspect_den the denominator of the video frame aspect ratio, overrides \p mlt_profile_s
+ *
*/
struct mlt_consumer_s
{
- /* We're implementing service here */
+ /** A consumer is a service. */
struct mlt_service_s parent;
- /* public virtual */
+ /** Start the consumer to pull frames (virtual function).
+ *
+ * \param mlt_consumer a consumer
+ * \return true if there was an error
+ */
int ( *start )( mlt_consumer );
+
+ /** Stop the consumer (virtual function).
+ *
+ * \param mlt_consumer a consumer
+ * \return true if there was an error
+ */
int ( *stop )( mlt_consumer );
+
+ /** Get whether the consumer is running or stopped (virtual function).
+ *
+ * \param mlt_consumer a consumer
+ * \return true if the consumer is stopped
+ */
int ( *is_stopped )( mlt_consumer );
+
+ /** The destructor virtual function
+ *
+ * \param mlt_consumer a consumer
+ */
void ( *close )( mlt_consumer );
- /* Private data */
- void *local;
- void *child;
+ void *local; /**< \private instance object */
+ void *child; /**< \private the object of a subclass */
int real_time;
int ahead;