typedef struct
{
+ int64_t last; // last timestamp seen on this stream
+ double average; // average time between packets
+ int id; // stream id
+} stream_timing_t;
+
+typedef struct
+{
hb_job_t * job;
hb_title_t * title;
volatile int * die;
hb_dvd_t * dvd;
- hb_buffer_t * ps;
hb_stream_t * stream;
+ stream_timing_t *stream_timing;
+ int64_t scr_offset;
hb_psdemux_t demux;
+ int scr_changes;
uint sequence;
int saw_video;
+ int st_slots; // size (in slots) of stream_timing array
} hb_reader_t;
/***********************************************************************
r->die = job->die;
r->sequence = 0;
- /*
- * when the scr changes we need to base the timing offset change on the
- * end of the current video frame otherwise we'll map the first frame
- * following the change over the current frame & it will be discarded.
- * Since the PTS only gives the start of the frame we need the average
- * frame duration to get its end. See the comments in the init_delay
- * setup in libhb/encx264.c to understand the following code.
- */
- r->demux.frame_duration = 90000. * (double)job->vrate_base / (double)job->vrate;
- if ( r->demux.frame_duration == 3753 )
- {
- r->demux.frame_duration = 4506;
- }
- r->demux.frame_duration += 3;
+ r->st_slots = 4;
+ r->stream_timing = calloc( sizeof(stream_timing_t), r->st_slots );
+ r->stream_timing[0].id = r->title->video_id;
+ r->stream_timing[0].average = 90000. * (double)job->vrate_base /
+ (double)job->vrate;
+ r->stream_timing[1].id = -1;
return hb_thread_init( "reader", ReaderFunc, r,
HB_NORMAL_PRIORITY );
}
-static void push_buf( hb_reader_t *r, hb_fifo_t *fifo, hb_buffer_t *buf )
+static void push_buf( const hb_reader_t *r, hb_fifo_t *fifo, hb_buffer_t *buf )
{
while( !*r->die && !r->job->done && hb_fifo_is_full( fifo ) )
{
hb_fifo_push( fifo, buf );
}
+// The MPEG STD (Standard Timing Decoder) essentially requires that we keep
+// per-stream timing so that when there's a timing discontinuity we can
+// seemlessly join packets on either side of the discontinuity. This join
+// requires that we know the timestamp of the previous packet and the
+// average inter-packet time (since we position the new packet at the end
+// of the previous packet). The next three routines keep track of this
+// per-stream timing.
+
+// find the per-stream timing state associated with 'buf'
+
+static stream_timing_t *id_to_st( hb_reader_t *r, const hb_buffer_t *buf )
+{
+ stream_timing_t *st = r->stream_timing;
+ while ( st->id != buf->id && st->id != -1)
+ {
+ ++st;
+ }
+ // if we haven't seen this stream add it.
+ if ( st->id == -1 )
+ {
+ // we keep the steam timing info in an array with some power-of-two
+ // number of slots. If we don't have two slots left (one for our new
+ // entry plus one for the "-1" eol) we need to expand the array.
+ int slot = st - r->stream_timing;
+ if ( slot + 1 >= r->st_slots )
+ {
+ r->st_slots *= 2;
+ r->stream_timing = realloc( r->stream_timing, r->st_slots *
+ sizeof(*r->stream_timing) );
+ st = r->stream_timing + slot;
+ }
+ st->id = buf->id;
+ st->last = buf->renderOffset;
+ st->average = 30.*90.;
+
+ st[1].id = -1;
+ }
+ return st;
+}
+
+// update the average inter-packet time of the stream associated with 'buf'
+// using a recursive low-pass filter with a 16 packet time constant.
+
+static void update_ipt( hb_reader_t *r, const hb_buffer_t *buf )
+{
+ stream_timing_t *st = id_to_st( r, buf );
+ double dt = buf->renderOffset - st->last;
+ st->average += ( dt - st->average ) * (1./16.);
+ st->last = buf->renderOffset;
+}
+
+// use the per-stream state associated with 'buf' to compute a new scr_offset
+// such that 'buf' will follow the previous packet of this stream separated
+// by the average packet time of the stream.
+
+static void new_scr_offset( hb_reader_t *r, const hb_buffer_t *buf )
+{
+ stream_timing_t *st = id_to_st( r, buf );
+ int64_t nxt = st->last + st->average - r->scr_offset;
+ r->scr_offset = buf->renderOffset - nxt;
+ r->scr_changes = r->demux.scr_changes;
+ st->last = buf->renderOffset;
+}
+
/***********************************************************************
* ReaderFunc
***********************************************************************
}
list = hb_list_init();
- r->ps = hb_buffer_init( HB_DVD_READ_BUFFER_SIZE );
+ hb_buffer_t *ps = hb_buffer_init( HB_DVD_READ_BUFFER_SIZE );
while( !*r->die && !r->job->done )
{
if (r->dvd)
{
- if( !hb_dvd_read( r->dvd, r->ps ) )
+ if( !hb_dvd_read( r->dvd, ps ) )
{
break;
}
}
else if (r->stream)
{
- if ( !hb_stream_read( r->stream, r->ps ) )
+ if ( !hb_stream_read( r->stream, ps ) )
{
break;
}
if ( r->title->demuxer == HB_NULL_DEMUXER )
{
- hb_demux_null( r->ps, list, &r->demux );
+ hb_demux_null( ps, list, &r->demux );
}
else
{
- hb_demux_ps( r->ps, list, &r->demux );
+ hb_demux_ps( ps, list, &r->demux );
}
while( ( buf = hb_list_item( list, 0 ) ) )
if ( buf->id == r->title->video_id && buf->start != -1 )
{
r->saw_video = 1;
- r->demux.scr_offset = buf->renderOffset;
+ r->scr_changes = r->demux.scr_changes;
+ new_scr_offset( r, buf );
hb_log( "reader: first SCR %llu scr_offset %llu",
- r->demux.last_scr, r->demux.scr_offset );
+ r->demux.last_scr, r->scr_offset );
}
else
{
{
if ( buf->start != -1 )
{
- /* this packet has a PTS - correct it for the initial
- video time offset & any timing discontinuities so that
- everything after this sees a continuous clock with 0
- being the time of the first video packet. */
- buf->start -= r->demux.scr_offset;
- buf->renderOffset -= r->demux.scr_offset;
+ if ( r->scr_changes == r->demux.scr_changes )
+ {
+ // This packet is referenced to the same SCR as the last.
+ // Update the average inter-packet time for this stream.
+ update_ipt( r, buf );
+ }
+ else
+ {
+ // This is the first audio or video packet after an SCR
+ // change. Compute a new scr offset that would make this
+ // packet follow the last of this stream with the correct
+ // average spacing.
+ new_scr_offset( r, buf );
+ }
+ // adjust timestamps to remove System Clock Reference offsets.
+ buf->start -= r->scr_offset;
+ buf->renderOffset -= r->scr_offset;
}
+
buf->sequence = r->sequence++;
/* if there are mutiple output fifos, send a copy of the
* buffer down all but the first (we have to not ship the
hb_fifo_push( r->job->fifo_mpeg2, hb_buffer_init(0) );
hb_list_empty( &list );
- hb_buffer_close( &r->ps );
+ hb_buffer_close( &ps );
if (r->dvd)
{
hb_dvd_stop( r->dvd );
hb_stream_close(&r->stream);
}
+ if ( r->stream_timing )
+ {
+ free( r->stream_timing );
+ }
+
hb_log( "reader: done. %d scr changes", r->demux.scr_changes );
free( r );
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