[vlc-devel] [PATCH] MKV: rework the PCR to match what avformat does

[Steve Lhomme]

Fixes #13575
Fixes #11847 which had time display issues

Applies on top of [PATCH] MKV: split time values between container ones and VLC ones

The new PCR logic is borrowed from
http://git.videolan.org/?p=vlc.git;a=blob;f=modules/demux/avformat/demux.c;hb=HEAD#l776

The PCR is now set just before sending the packet es_out_Send() rather than
before treating the new read Block (ie the previous PCR value)

i_last_dts is now only valid for active tracks

the i_pts is not set to 0 in a lace as it disturbs seeking performance
---
 modules/demux/mkv/mkv.cpp | 49 ++++++++++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/modules/demux/mkv/mkv.cpp b/modules/demux/mkv/mkv.cpp
index 4824c23..f1cf718 100644
--- a/modules/demux/mkv/mkv.cpp
+++ b/modules/demux/mkv/mkv.cpp
@@ -332,7 +332,7 @@ static int Control( demux_t *p_demux, int i_query, va_list args )
         case DEMUX_GET_POSITION:
             pf = (double*)va_arg( args, double * );
             if ( p_sys->f_duration > 0.0 )
-                *pf = (double)((p_sys->i_pts >= p_sys->i_start_pts ? p_sys->i_pts : p_sys->i_start_pts ) - VLC_TS_0) /
+                *pf = (double)((p_sys->i_pcr >= p_sys->i_start_pts ? p_sys->i_pcr : p_sys->i_start_pts ) - VLC_TS_0) /
                     (1000.0 * p_sys->f_duration);
             return VLC_SUCCESS;
 
@@ -347,7 +347,7 @@ static int Control( demux_t *p_demux, int i_query, va_list args )
 
         case DEMUX_GET_TIME:
             pi64 = (int64_t*)va_arg( args, int64_t * );
-            *pi64 = p_sys->i_pts - VLC_TS_0;
+            *pi64 = p_sys->i_pcr - VLC_TS_0;
             return VLC_SUCCESS;
 
         case DEMUX_GET_TITLE_INFO:
@@ -693,18 +693,35 @@ msg_Dbg( p_demux, "block (track=%d) i_dts: %"PRId64" / i_pts: %"PRId64, tk->i_nu
                 (double) p_segment->i_timescale / ( 1000.0 * i_number_frames );
         }
 
-        /* FIXME remove when VLC_TS_INVALID work is done */
-        if( i_frame == 0 || p_block->i_dts > VLC_TS_INVALID )
-            p_block->i_dts += VLC_TS_0;
-        if( !tk->b_dts_only && ( i_frame == 0 || p_block->i_pts > VLC_TS_INVALID ) )
-            p_block->i_pts += VLC_TS_0;
+        // find the latest DTS for an active track
+        ts_time_t i_ts_max = INT64_MIN;
+        for( size_t i = 0; i < p_segment->tracks.size(); i++ )
+        {
+            mkv_track_t *tk = p_segment->tracks[i];
+            if( tk->i_last_dts > VLC_TS_INVALID )
+                i_ts_max = __MAX( i_ts_max, tk->i_last_dts );
+        }
+
+        // find the earliest DTS less than 10 clock ticks away from the latest DTS
+        ts_time_t i_ts_min = INT64_MAX;
+        for( size_t i = 0; i < p_segment->tracks.size(); i++ )
+        {
+            mkv_track_t *tk = p_segment->tracks[i];
+            if( tk->i_last_dts > VLC_TS_INVALID && tk->i_last_dts + 10 * CLOCK_FREQ >= i_ts_max )
+                i_ts_min = __MIN( i_ts_min, tk->i_last_dts );
+        }
+
+        // the PCR is the earliest active DTS if we found one
+        if( i_ts_min != INT64_MAX && ( i_ts_min > p_sys->i_pcr || p_sys->i_pcr == VLC_TS_INVALID ) )
+        {
+            p_sys->i_pcr = i_ts_min;
+            es_out_Control( p_demux->out, ES_OUT_SET_PCR, i_ts_min );
+        }
 
         es_out_Send( p_demux->out, tk->p_es, p_block );
 
         /* use time stamp only for first block */
-        i_pts = ( tk->i_default_duration )?
-                 i_pts + tk->i_default_duration:
-                 VLC_TS_INVALID;
+        i_pts += tk->i_default_duration ? tk->i_default_duration : 1;
     }
 }
 
@@ -779,18 +796,6 @@ static int Demux( demux_t *p_demux)
             p_sys->i_pts = (ts_time_t)block->GlobalTimecode() / INT64_C(1000);
         p_sys->i_pts += p_sys->i_chapter_time + VLC_TS_0;
 
-        mtime_t i_pcr = VLC_TS_INVALID;
-        for( size_t i = 0; i < p_segment->tracks.size(); i++)
-            if( p_segment->tracks[i]->i_last_dts > VLC_TS_INVALID &&
-                ( p_segment->tracks[i]->i_last_dts < i_pcr || i_pcr == VLC_TS_INVALID ))
-                i_pcr = p_segment->tracks[i]->i_last_dts;
-
-        if( i_pcr > p_sys->i_pcr + 300000 )
-        {
-            es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_sys->i_pcr );
-            p_sys->i_pcr = i_pcr;
-        }
-
         if( p_sys->i_pts >= p_sys->i_start_pts  )
         {
             if ( p_vsegment->UpdateCurrentToChapter( *p_demux ) )
-- 
2.3.2