Changeset 3814 for pjproject/branches/1.x/pjmedia/include/pjmedia/jbuf.h

Timestamp:

Oct 13, 2011 9:02:41 AM (13 years ago)

Author:

nanang

Message:

Re #1378:

• Implemented new algorithm for JB progressive discard.
• Added new API and for setting JB discard algorithm at run-time.
• Updated JB test for the new algorithm.

File:

• pjproject/branches/1.x/pjmedia/include/pjmedia/jbuf.h (modified) (6 diffs)

pjproject/branches/1.x/pjmedia/include/pjmedia/jbuf.h

@@ -49 +49 @@
  * Types of frame returned by the jitter buffer.
  */
-enum pjmedia_jb_frame_type 
+typedef enum pjmedia_jb_frame_type 
 {
     PJMEDIA_JB_MISSING_FRAME       = 0, /**< No frame because it's missing  */
@@ -57 +57 @@
     PJMEDIA_JB_ZERO_EMPTY_FRAME    = 3  /**< Zero frame is being returned
                                              because JB is empty.           */
-};
-
-
-/**
- * @see pjmedia_jb_frame_type.
- */
-typedef enum pjmedia_jb_frame_type pjmedia_jb_frame_type;
+} pjmedia_jb_frame_type;
+
+
+/**
+ * Enumeration of jitter buffer discard algorithm. The jitter buffer
+ * continuously calculates the jitter level to get the optimum latency at
+ * any time and in order to adjust the latency, the jitter buffer may need
+ * to discard some frames.
+ */
+typedef enum pjmedia_jb_discard_algo
+{
+    /**
+     * Jitter buffer should not discard any frame, except when the jitter
+     * buffer is full and a new frame arrives, one frame will be discarded
+     * to make space for the new frame.
+     */
+    PJMEDIA_JB_DISCARD_NONE        = 0,
+
+    /**
+     * Only discard one frame in at least 200ms when the latency is considered
+     * much higher than it should be. When the jitter buffer is full and a new
+     * frame arrives, one frame will be discarded to make space for the new
+     * frame.
+     */
+    PJMEDIA_JB_DISCARD_STATIC,
+
+    /**
+     * The discard rate is dynamically calculated based on actual parameters
+     * such as jitter level and latency. When the jitter buffer is full and
+     * a new frame arrives, one frame will be discarded to make space for the
+     * new frame.
+     */
+    PJMEDIA_JB_DISCARD_PROGRESSIVE
+
+} pjmedia_jb_discard_algo;
 
 
@@ -69 +97 @@
  * This structure describes jitter buffer state.
  */
-struct pjmedia_jb_state
+typedef struct pjmedia_jb_state
 {
     /* Setting */
@@ -90 +118 @@
     unsigned    discard;            /**< Number of discarded frames.        */
     unsigned    empty;              /**< Number of empty on GET events.     */
-};
-
-
-/**
- * @see pjmedia_jb_state
- */
-typedef struct pjmedia_jb_state pjmedia_jb_state;
+} pjmedia_jb_state;
 
 
@@ -114 +136 @@
  * Create an adaptive jitter buffer according to the specification. If
  * application wants to have a fixed jitter buffer, it may call
- * #pjmedia_jbuf_set_fixed() after the jitter buffer is created.
+ * #pjmedia_jbuf_set_fixed() after the jitter buffer is created. Also
+ * if application wants to alter the discard algorithm, which the default
+ * PJMEDIA_JB_DISCARD_PROGRESSIVE, it may call #pjmedia_jbuf_set_discard().
  *
  * This function may allocate large chunk of memory to keep the frames in 
@@ -178 +202 @@
                                                 unsigned min_prefetch,
                                                 unsigned max_prefetch);
+
+
+/**
+ * Set the jitter buffer discard algorithm. The default discard algorithm,
+ * set in jitter buffer creation, is PJMEDIA_JB_DISCARD_PROGRESSIVE.
+ *
+ * @param jb            The jitter buffer.
+ * @param algo          The discard algorithm to be used.
+ *
+ * @return              PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjmedia_jbuf_set_discard(pjmedia_jbuf *jb,
+                                              pjmedia_jb_discard_algo algo);