Changeset 3998 for pjproject/trunk

Timestamp:

Mar 30, 2012 6:46:48 AM (12 years ago)

Author:

nanang

Message:

Misc (re #1446): Avoid unnecessary high latency caused by clock drift or call setup lag by overriding initial framerate setting to be 1.5x higher in video stream decoding direction. Note that a previous method in r3972 has just been cancelled.

Location:

pjproject/trunk/pjmedia/src

Files:

• pjmedia-codec/ffmpeg_codecs.c (modified) (1 diff)
• pjmedia/vid_stream.c (modified) (1 diff)

pjproject/trunk/pjmedia/src/pjmedia-codec/ffmpeg_codecs.c

@@ -924 +924 @@
     pjmedia_format_init_video(&attr->dec_fmt, desc->info.dec_fmt_id[0],
                               desc->size.w, desc->size.h,
-                              desc->fps.num*3/2, desc->fps.denum);
+                              desc->fps.num, desc->fps.denum);
 
     /* Decoding fmtp */

pjproject/trunk/pjmedia/src/pjmedia/vid_stream.c

@@ -1393 +1393 @@
                            vfd_enc->fps.denum / vfd_enc->fps.num;
 
+    /* Override the initial framerate in the decoding direction. This initial
+     * value will be used by the renderer to configure its clock, and setting
+     * it to a bit higher value can avoid the possibility of high latency
+     * caused by clock drift (remote encoder clock runs slightly faster than
+     * local renderer clock) or video setup lag. Note that the actual framerate
+     * will be continuously calculated based on the incoming RTP timestamps.
+     */
+    vfd_dec->fps.num = vfd_dec->fps.num * 3 / 2;
+
     /* Create decoder channel */
     status = create_channel( pool, stream, PJMEDIA_DIR_DECODING,