Added an option (clock-jitter) to control the maximum compensated jitter.

Only input jitters lower than clock-jitter will be compensated. You
may set it to 0 to avoid having the latency increased automatically
by VLC.

src/input/es_out.c

@@ -148,6 +148,7 @@ struct es_out_sys_t
 
     /* Clock configuration */
     mtime_t     i_pts_delay;
+    mtime_t     i_pts_jitter;
     int         i_cr_average;
     int         i_rate;
 
@@ -310,6 +311,7 @@ es_out_t *input_EsOutNew( input_thread_t *p_input, int i_rate )
 
     p_sys->i_rate = i_rate;
     p_sys->i_pts_delay = 0;
+    p_sys->i_pts_jitter = 0;
     p_sys->i_cr_average = 0;
 
     p_sys->b_buffering = true;
@@ -2307,23 +2309,32 @@ static int EsOutControlLocked( es_out_t *out, int i_query, va_list args )
                 else if( b_late && ( !p_sys->p_input->p->p_sout ||
                                      !p_sys->p_input->p->b_out_pace_control ) )
                 {
+                    const mtime_t i_pts_delay_base = p_sys->i_pts_delay - p_sys->i_pts_jitter;
                     mtime_t i_pts_delay = input_clock_GetJitter( p_pgrm->p_clock );
 
                     /* Avoid dangerously high value */
-                    const mtime_t i_pts_delay_max = 30000000;
-                    if( i_pts_delay > i_pts_delay_max )
-                        i_pts_delay = __MAX( i_pts_delay_max, p_sys->i_pts_delay );
-
-                    /* Force a rebufferization when we are too late */
+                    const mtime_t i_jitter_max = INT64_C(1000) * var_InheritInteger( p_sys->p_input, "clock-jitter" );
+                    if( i_pts_delay > __MIN( i_pts_delay_base + i_jitter_max, INPUT_PTS_DELAY_MAX ) )
+                    {
+                        msg_Err( p_sys->p_input,
+                                 "ES_OUT_SET_(GROUP_)PCR  is called too late (jitter of %d ms ingnored)",
+                                 (int)(i_pts_delay - i_pts_delay_base) / 1000 );
+                        i_pts_delay = p_sys->i_pts_delay;
+                    }
+                    else
+                    {
                         msg_Err( p_sys->p_input,
-                             "ES_OUT_SET_(GROUP_)PCR  is called too late, increasing pts_delay to %d ms",
+                                 "ES_OUT_SET_(GROUP_)PCR  is called too late (pts_delay increased to %d ms)",
                                  (int)(i_pts_delay/1000) );
+                    }
+
+                    /* Force a rebufferization when we are too late */
 
                     /* It is not really good, as we throw away already buffered data
                      * TODO have a mean to correctly reenter bufferization */
                     es_out_Control( out, ES_OUT_RESET_PCR );
 
-                    es_out_SetJitter( out, i_pts_delay, 0, p_sys->i_cr_average );
+                    es_out_SetJitter( out, i_pts_delay_base, i_pts_delay - i_pts_delay_base, p_sys->i_cr_average );
                 }
             }
             return VLC_SUCCESS;
@@ -2602,14 +2613,16 @@ static int EsOutControlLocked( es_out_t *out, int i_query, va_list args )
             mtime_t i_pts_jitter = (mtime_t)va_arg( args, mtime_t );
             int     i_cr_average = (int)va_arg( args, int );
 
-            if( i_pts_delay + i_pts_jitter == p_sys->i_pts_delay &&
-                i_cr_average == p_sys->i_cr_average )
-                return VLC_SUCCESS;
+            bool b_change_clock =
+                i_pts_delay + i_pts_jitter != p_sys->i_pts_delay ||
+                i_cr_average != p_sys->i_cr_average;
 
+            assert( i_pts_jitter >= 0 );
             p_sys->i_pts_delay  = i_pts_delay + i_pts_jitter;
+            p_sys->i_pts_jitter = i_pts_jitter;
             p_sys->i_cr_average = i_cr_average;
 
-            for( int i = 0; i < p_sys->i_pgrm; i++ )
+            for( int i = 0; i < p_sys->i_pgrm && b_change_clock; i++ )
                 input_clock_SetJitter( p_sys->pgrm[i]->p_clock,
                                        i_pts_delay + i_pts_jitter, i_cr_average );
             return VLC_SUCCESS;

src/input/input.c

@@ -110,9 +110,6 @@ static void SubtitleAdd( input_thread_t *p_input, char *psz_subtitle, bool b_for
 
 static void input_ChangeState( input_thread_t *p_input, int i_state ); /* TODO fix name */
 
-/* Do not let a pts_delay from access/demux go beyong 60s */
-#define INPUT_PTS_DELAY_MAX INT64_C(60000000)
-
 #undef input_Create
 /**
  * Create a new input_thread_t.

src/input/input_internal.h

@@ -220,6 +220,9 @@ enum input_control_e
  */
 void input_ControlPush( input_thread_t *, int i_type, vlc_value_t * );
 
+/* Bound pts_delay */
+#define INPUT_PTS_DELAY_MAX INT64_C(60000000)
+
 /**********************************************************************
  * Item metadata
  **********************************************************************/

src/libvlc-module.c

@@ -634,6 +634,11 @@ static const char *const ppsz_pos_descriptions[] =
     "real-time sources. Use this if you experience jerky playback of " \
     "network streams.")
 
+#define CLOCK_JITTER_TEXT N_("Clock jitter")
+#define CLOCK_JITTER_LONGTEXT N_( \
+    "It tells the clock algorithms what is the maximal input jitter that " \
+    "is considered valid and can be compensated (in milliseconds)" )
+
 #define NETSYNC_TEXT N_("Network synchronisation" )
 #define NETSYNC_LONGTEXT N_( "This allows you to remotely " \
         "synchronise clocks for server and client. The detailed settings " \
@@ -1900,6 +1905,9 @@ vlc_module_begin ()
     add_integer( "clock-synchro", -1, NULL, CLOCK_SYNCHRO_TEXT,
                  CLOCK_SYNCHRO_LONGTEXT, true )
         change_integer_list( pi_clock_values, ppsz_clock_descriptions, NULL )
+    add_integer( "clock-jitter", 5 * CLOCK_FREQ/1000, NULL, CLOCK_JITTER_TEXT,
+              CLOCK_JITTER_LONGTEXT, true )
+        change_safe()
 
     add_bool( "network-synchronisation", false, NULL, NETSYNC_TEXT,
               NETSYNC_LONGTEXT, true )