[vlc-devel] [PATCH 4/5] input: handle "sub-fps" with a new control

[Thomas Guillem]

We now change the slave demux rate according to the requested subtitle fps and
the main demuxer fps.

Example: Video is 24fps but the subtitle is 26fps. In that case, we want to
slow down the subtitle demuxer. Setting "sub-fps" to 26 will change the rate
of the subtitle demuxer to 0.92.
---
 src/input/input.c          | 32 ++++++++++++++++++++++++++++++++
 src/input/input_internal.h |  3 +++
 2 files changed, 35 insertions(+)

diff --git a/src/input/input.c b/src/input/input.c
index 0595b8e73a..995287c56f 100644
--- a/src/input/input.c
+++ b/src/input/input.c
@@ -996,6 +996,16 @@ static bool SlaveExists( input_item_slave_t **pp_slaves, int i_slaves,
     return false;
 }
 
+static void SlaveRequestNewRate( input_thread_t *p_input, float f_slave_fps )
+{
+    input_thread_private_t *priv = input_priv(p_input);
+    const float f_fps = input_priv(p_input)->master->f_fps;
+    if( f_fps > 1.f && f_slave_fps > 1.f )
+        priv->i_slaves_requested_rate = INPUT_RATE_DEFAULT / ( f_fps / f_slave_fps );
+    else if ( priv->i_slaves_rate != 0 )
+        priv->i_slaves_requested_rate = INPUT_RATE_DEFAULT;
+}
+
 static void SetSubtitlesOptions( input_thread_t *p_input )
 {
     input_thread_private_t *priv = input_priv(p_input);
@@ -1005,6 +1015,7 @@ static void SetSubtitlesOptions( input_thread_t *p_input )
     if( f_fps > 1.f )
     {
         var_SetFloat( p_input, "sub-original-fps", f_fps );
+        SlaveRequestNewRate( p_input, var_InheritFloat( p_input, "sub-fps" ) );
     }
 
     int64_t sub_delay = var_InheritInteger( p_input, "sub-delay" );
@@ -2229,6 +2240,9 @@ static bool Control( input_thread_t *p_input,
                 }
             }
             break;
+        case INPUT_CONTROL_SET_SLAVE_FPS:
+            SlaveRequestNewRate( p_input, param.val.f_float );
+            break;
 
         case INPUT_CONTROL_SET_RECORD_STATE:
             val = param.val;
@@ -2846,6 +2860,7 @@ static void InputSourceMeta( input_thread_t *p_input,
 
 static void SlaveDemux( input_thread_t *p_input )
 {
+    input_thread_private_t *priv = input_priv(p_input);
     vlc_tick_t i_time;
     int i;
 
@@ -2863,6 +2878,17 @@ static void SlaveDemux( input_thread_t *p_input )
         if( in->b_eof )
             continue;
 
+        if( priv->i_slaves_requested_rate != 0
+         && priv->i_slaves_requested_rate != priv->i_slaves_rate
+         && in->b_can_rate_control )
+        {
+            if( priv->i_slaves_rate != 0 ) /* Don't reset when it's the first time */
+                es_out_Control( priv->p_es_out, ES_OUT_RESET_PCR );
+            int i_new_rate = priv->i_slaves_requested_rate;
+            demux_Control( in->p_demux, DEMUX_SET_RATE, &i_new_rate );
+
+        }
+
         /* Call demux_Demux until we have read enough data */
         if( demux_Control( in->p_demux, DEMUX_SET_NEXT_DEMUX_TIME, i_time ) )
         {
@@ -2898,6 +2924,12 @@ static void SlaveDemux( input_thread_t *p_input )
             in->b_eof = true;
         }
     }
+
+    if( priv->i_slaves_requested_rate != 0 )
+    {
+        priv->i_slaves_rate = priv->i_slaves_requested_rate;
+        priv->i_slaves_requested_rate = 0;
+    }
 }
 
 static void SlaveSeek( input_thread_t *p_input )
diff --git a/src/input/input_internal.h b/src/input/input_internal.h
index bcc8f06a91..a5b536f152 100644
--- a/src/input/input_internal.h
+++ b/src/input/input_internal.h
@@ -175,6 +175,8 @@ typedef struct input_thread_private_t
     /* Slave sources (subs, and others) */
     int            i_slave;
     input_source_t **slave;
+    unsigned i_slaves_rate;
+    unsigned i_slaves_requested_rate;
 
     /* Last ES added */
     enum es_format_category_e i_last_es_cat;
@@ -252,6 +254,7 @@ enum input_control_e
     INPUT_CONTROL_SET_SPU_DELAY,
 
     INPUT_CONTROL_ADD_SLAVE,
+    INPUT_CONTROL_SET_SLAVE_FPS,
 
     INPUT_CONTROL_SET_RECORD_STATE,
 
-- 
2.19.1