/*****************************************************************************
* vpar_synchro.c : frame dropping routines
*****************************************************************************
* Copyright (C) 1999-2001 VideoLAN
* $Id: vpar_synchro.c,v 1.4 2001/12/10 04:53:11 sam Exp $
*
* Authors: Christophe Massiot <massiot@via.ecp.fr>
* Samuel Hocevar <sam@via.ecp.fr>
* Jean-Marc Dressler <polux@via.ecp.fr>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
*****************************************************************************/
/*
* DISCUSSION : How to Write an efficient Frame-Dropping Algorithm
* ==========
*
* This implementation is based on mathematical and statistical
* developments. Older implementations used an enslavement, considering
* that if we're late when reading an I picture, we will decode one frame
* less. It had a tendancy to derive, and wasn't responsive enough, which
* would have caused trouble with the stream control stuff.
*
* 1. Structure of a picture stream
* =============================
* Between 2 I's, we have for instance :
* I B P B P B P B P B P B I
* t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12
* Please bear in mind that B's and IP's will be inverted when displaying
* (decoding order != presentation order). Thus, t1 < t0.
*
* 2. Definitions
* ===========
* t[0..12] : Presentation timestamps of pictures 0..12.
* t : Current timestamp, at the moment of the decoding.
* T : Picture period, T = 1/frame_rate.
* tau[I,P,B] : Mean time to decode an [I,P,B] picture.
* tauYUV : Mean time to render a picture (given by the video_output).
* tau�[I,P,B] = 2 * tau[I,P,B] + tauYUV
* : Mean time + typical difference (estimated to tau/2, that
* needs to be confirmed) + render time.
* DELTA : A given error margin.
*
* 3. General considerations
* ======================
* We define three types of machines :
* 14T > tauI : machines capable of decoding all I pictures
* 2T > tauP : machines capable of decoding all P pictures
* T > tauB : machines capable of decoding all B pictures
*
* 4. Decoding of an I picture
* ========================
* On fast machines, we decode all I's.
* Otherwise :
* We can decode an I picture if we simply have enough time to decode it
* before displaying :
* t0 - t > tau�I + DELTA
*
* 5. Decoding of a P picture
* =======================
* On fast machines, we decode all P's.
* Otherwise :
* First criterion : have time to decode it.
* t2 - t > tau�P + DELTA
*
* Second criterion : it shouldn't prevent us from displaying the forthcoming
* I picture, which is more important.
* t12 - t > tau�P + tau�I + DELTA
*
* 6. Decoding of a B picture
* =======================
* On fast machines, we decode all B's. Otherwise :
* t1 - t > tau�B + DELTA
* Since the next displayed I or P is already decoded, we don't have to
* worry about it.
*
* I hope you will have a pleasant flight and do not forget your life
* jacket.
* --Meuuh (2000-12-29)
*/
/*****************************************************************************
* Preamble
*****************************************************************************/
#include "defs.h"
#include <string.h> /* memcpy(), memset() */
#include "common.h"
#include "intf_msg.h"
#include "threads.h"
#include "mtime.h"
#include "video.h"
#include "video_output.h"
#include "stream_control.h"
#include "input_ext-dec.h"
#include "vdec_ext-plugins.h"
#include "vpar_pool.h"
#include "video_parser.h"
#include "modules_export.h"
/*
* Local prototypes
*/
static int SynchroType( void );
/* Error margins */
#define DELTA (int)(0.075*CLOCK_FREQ)
#define DEFAULT_NB_P 5
#define DEFAULT_NB_B 1
/*****************************************************************************
* vpar_SynchroInit : You know what ?
*****************************************************************************/
void vpar_SynchroInit( vpar_thread_t * p_vpar )
{
p_vpar->synchro.i_type = SynchroType();
/* We use a fake stream pattern, which is often right. */
p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p = DEFAULT_NB_P;
p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b = DEFAULT_NB_B;
memset( p_vpar->synchro.p_tau, 0, 4 * sizeof(mtime_t) );
memset( p_vpar->synchro.pi_meaningful, 0, 4 * sizeof(unsigned int) );
p_vpar->synchro.b_dropped_last = 0;
p_vpar->synchro.current_pts = mdate() + DEFAULT_PTS_DELAY;
p_vpar->synchro.backward_pts = 0;
p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period = 0;
p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic =
p_vpar->synchro.i_pic = 0;
}
/*****************************************************************************
* vpar_SynchroChoose : Decide whether we will decode a picture or not
*****************************************************************************/
boolean_t vpar_SynchroChoose( vpar_thread_t * p_vpar, int i_coding_type,
int i_structure )
{
/* For clarity reasons, we separated the special synchros code from the
* mathematical synchro */
if( p_vpar->synchro.i_type != VPAR_SYNCHRO_DEFAULT )
{
switch( i_coding_type )
{
case I_CODING_TYPE:
/* I, IP, IP+, IPB */
if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus )
{
p_vpar->synchro.b_dropped_last = 1;
}
return( 1 );
case P_CODING_TYPE:
if( p_vpar->synchro.i_type == VPAR_SYNCHRO_I ) /* I */
{
return( 0 );
}
if( p_vpar->synchro.i_type == VPAR_SYNCHRO_Iplus ) /* I+ */
{
if( p_vpar->synchro.b_dropped_last )
{
p_vpar->synchro.b_dropped_last = 0;
return( 1 );
}
else
{
return( 0 );
}
}
return( 1 ); /* IP, IP+, IPB */
case B_CODING_TYPE:
if( p_vpar->synchro.i_type <= VPAR_SYNCHRO_IP ) /* I, IP */
{
return( 0 );
}
else if( p_vpar->synchro.i_type == VPAR_SYNCHRO_IPB ) /* IPB */
{
return( 1 );
}
p_vpar->synchro.b_dropped_last ^= 1; /* IP+ */
return( !p_vpar->synchro.b_dropped_last );
}
return( 0 ); /* never reached but gcc yells at me */
}
else
{
#define TAU_PRIME( coding_type ) (p_vpar->synchro.p_tau[(coding_type)] \
+ (p_vpar->synchro.p_tau[(coding_type)] >> 1) \
+ tau_yuv)
#define S p_vpar->synchro
/* VPAR_SYNCHRO_DEFAULT */
mtime_t now, period, tau_yuv;
mtime_t pts = 0;
boolean_t b_decode = 0;
#ifdef TRACE_VPAR
char p_date[MSTRTIME_MAX_SIZE];
#endif
now = mdate();
period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate
* p_vpar->sequence.i_current_rate / DEFAULT_RATE;
vlc_mutex_lock( &p_vpar->p_vout->change_lock );
tau_yuv = p_vpar->p_vout->render_time;
vlc_mutex_unlock( &p_vpar->p_vout->change_lock );
switch( i_coding_type )
{
case I_CODING_TYPE:
if( S.backward_pts )
{
pts = S.backward_pts;
}
else
{
/* displaying order : B B P B B I
* ^ ^
* | +- current picture
* +- current PTS
*/
pts = S.current_pts + period * (S.i_n_b + 2);
}
if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
S.p_tau[I_CODING_TYPE] )
{
b_decode = 1;
}
else
{
b_decode = (pts - now) > (TAU_PRIME(I_CODING_TYPE) + DELTA);
}
if( !b_decode )
intf_WarnMsg( 1, "vpar synchro warning: trashing I (%lld)",
pts - now);
break;
case P_CODING_TYPE:
if( S.backward_pts )
{
pts = S.backward_pts;
}
else
{
pts = S.current_pts + period * (S.i_n_b + 1);
}
if( (1 + S.i_n_p * (S.i_n_b + 1)) * period >
S.p_tau[I_CODING_TYPE] )
{
if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
{
/* Security in case we're _really_ late */
b_decode = (pts - now > 0);
}
else
{
b_decode = (pts - now) > (TAU_PRIME(P_CODING_TYPE) + DELTA);
/* next I */
b_decode &= (pts - now
+ period
* ( (S.i_n_p - S.i_eta_p) * (1 + S.i_n_b) - 1 ))
> (TAU_PRIME(P_CODING_TYPE)
+ TAU_PRIME(I_CODING_TYPE) + DELTA);
}
}
else
{
b_decode = 0;
}
break;
case B_CODING_TYPE:
pts = S.current_pts;
if( (S.i_n_b + 1) * period > S.p_tau[P_CODING_TYPE] )
{
b_decode = (pts - now) > (TAU_PRIME(B_CODING_TYPE) + DELTA);
}
else
{
b_decode = 0;
}
}
#ifdef TRACE_VPAR
intf_DbgMsg("vpar synchro debug: %s picture scheduled for %s, %s (%lld)",
i_coding_type == B_CODING_TYPE ? "B" :
(i_coding_type == P_CODING_TYPE ? "P" : "I"),
mstrtime(p_date, pts), b_decode ? "decoding" : "trashed",
S.p_tau[i_coding_type]);
#endif
if( !b_decode )
{
S.i_not_chosen_pic++;
}
return( b_decode );
#undef S
#undef TAU_PRIME
}
}
/*****************************************************************************
* vpar_SynchroTrash : Update counters when we trash a picture
*****************************************************************************/
void vpar_SynchroTrash( vpar_thread_t * p_vpar, int i_coding_type,
int i_structure )
{
p_vpar->synchro.i_trashed_pic++;
}
/*****************************************************************************
* vpar_SynchroDecode : Update timers when we decide to decode a picture
*****************************************************************************/
void vpar_SynchroDecode( vpar_thread_t * p_vpar, int i_coding_type,
int i_structure )
{
p_vpar->synchro.decoding_start = mdate();
}
/*****************************************************************************
* vpar_SynchroEnd : Called when the image is totally decoded
*****************************************************************************/
void vpar_SynchroEnd( vpar_thread_t * p_vpar, int i_coding_type,
int i_structure, int i_garbage )
{
mtime_t tau;
if( !i_garbage )
{
tau = mdate() - p_vpar->synchro.decoding_start;
/* If duration too high, something happened (pause ?), so don't
* take it into account. */
if( tau < 3 * p_vpar->synchro.p_tau[i_coding_type]
|| !p_vpar->synchro.pi_meaningful[i_coding_type] )
{
/* Mean with average tau, to ensure stability. */
p_vpar->synchro.p_tau[i_coding_type] =
(p_vpar->synchro.pi_meaningful[i_coding_type]
* p_vpar->synchro.p_tau[i_coding_type] + tau)
/ (p_vpar->synchro.pi_meaningful[i_coding_type] + 1);
if( p_vpar->synchro.pi_meaningful[i_coding_type] < MAX_PIC_AVERAGE )
{
p_vpar->synchro.pi_meaningful[i_coding_type]++;
}
}
#ifdef TRACE_VPAR
intf_DbgMsg("vpar synchro debug: finished decoding %s (%lld)",
i_coding_type == B_CODING_TYPE ? "B" :
(i_coding_type == P_CODING_TYPE ? "P" : "I"), tau);
#endif
}
else
{
intf_DbgMsg("vpar synchro debug: aborting %s",
i_coding_type == B_CODING_TYPE ? "B" :
(i_coding_type == P_CODING_TYPE ? "P" : "I"));
}
}
/*****************************************************************************
* vpar_SynchroDate : When an image has been decoded, ask for its date
*****************************************************************************/
mtime_t vpar_SynchroDate( vpar_thread_t * p_vpar )
{
/* No need to lock, since PTS are only used by the video parser. */
return( p_vpar->synchro.current_pts );
}
/*****************************************************************************
* vpar_SynchroNewPicture: Update stream structure and PTS
*****************************************************************************/
void vpar_SynchroNewPicture( vpar_thread_t * p_vpar, int i_coding_type,
int i_repeat_field )
{
mtime_t period = 1000000 * 1001 / p_vpar->sequence.i_frame_rate
* p_vpar->sequence.i_current_rate / DEFAULT_RATE;
#if 0
mtime_t now = mdate();
#endif
switch( i_coding_type )
{
case I_CODING_TYPE:
if( p_vpar->synchro.i_eta_p
&& p_vpar->synchro.i_eta_p != p_vpar->synchro.i_n_p )
{
intf_WarnMsg( 3, "vpar info: stream periodicity changed "
"from P[%d] to P[%d]",
p_vpar->synchro.i_n_p, p_vpar->synchro.i_eta_p );
p_vpar->synchro.i_n_p = p_vpar->synchro.i_eta_p;
}
p_vpar->synchro.i_eta_p = p_vpar->synchro.i_eta_b = 0;
if( p_main->b_stats && p_vpar->synchro.i_type == VPAR_SYNCHRO_DEFAULT )
{
intf_Msg( "vpar synchro stats: I(%lld) P(%lld)[%d] B(%lld)[%d] YUV(%lld) : trashed %d:%d/%d",
p_vpar->synchro.p_tau[I_CODING_TYPE],
p_vpar->synchro.p_tau[P_CODING_TYPE],
p_vpar->synchro.i_n_p,
p_vpar->synchro.p_tau[B_CODING_TYPE],
p_vpar->synchro.i_n_b,
p_vpar->p_vout->render_time,
p_vpar->synchro.i_not_chosen_pic,
p_vpar->synchro.i_trashed_pic -
p_vpar->synchro.i_not_chosen_pic,
p_vpar->synchro.i_pic );
p_vpar->synchro.i_trashed_pic = p_vpar->synchro.i_not_chosen_pic
= p_vpar->synchro.i_pic = 0;
}
break;
case P_CODING_TYPE:
p_vpar->synchro.i_eta_p++;
if( p_vpar->synchro.i_eta_b
&& p_vpar->synchro.i_eta_b != p_vpar->synchro.i_n_b )
{
intf_WarnMsg( 3, "vpar info: stream periodicity changed "
"from B[%d] to B[%d]",
p_vpar->synchro.i_n_b, p_vpar->synchro.i_eta_b );
p_vpar->synchro.i_n_b = p_vpar->synchro.i_eta_b;
}
p_vpar->synchro.i_eta_b = 0;
break;
case B_CODING_TYPE:
p_vpar->synchro.i_eta_b++;
break;
}
p_vpar->synchro.current_pts += p_vpar->synchro.i_current_period
* (period >> 1);
#define PTS_THRESHOLD (period >> 2)
if( i_coding_type == B_CODING_TYPE )
{
/* A video frame can be displayed 1, 2 or 3 times, according to
* repeat_first_field, top_field_first, progressive_sequence and
* progressive_frame. */
p_vpar->synchro.i_current_period = i_repeat_field;
if( p_vpar->sequence.next_pts )
{
if( p_vpar->sequence.next_pts - p_vpar->synchro.current_pts
> PTS_THRESHOLD
|| p_vpar->synchro.current_pts - p_vpar->sequence.next_pts
> PTS_THRESHOLD )
{
intf_WarnMsg( 2,
"vpar synchro warning: pts != current_date (%lld)",
p_vpar->synchro.current_pts
- p_vpar->sequence.next_pts );
}
p_vpar->synchro.current_pts = p_vpar->sequence.next_pts;
p_vpar->sequence.next_pts = 0;
}
}
else
{
p_vpar->synchro.i_current_period = p_vpar->synchro.i_backward_period;
p_vpar->synchro.i_backward_period = i_repeat_field;
if( p_vpar->synchro.backward_pts )
{
if( p_vpar->sequence.next_dts &&
(p_vpar->sequence.next_dts - p_vpar->synchro.backward_pts
> PTS_THRESHOLD
|| p_vpar->synchro.backward_pts - p_vpar->sequence.next_dts
> PTS_THRESHOLD) )
{
intf_WarnMsg( 2,
"vpar synchro warning: backward_pts != dts (%lld)",
p_vpar->sequence.next_dts
- p_vpar->synchro.backward_pts );
}
if( p_vpar->synchro.backward_pts - p_vpar->synchro.current_pts
> PTS_THRESHOLD
|| p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts
> PTS_THRESHOLD )
{
intf_WarnMsg( 2,
"vpar synchro warning: backward_pts != current_pts (%lld)",
p_vpar->synchro.current_pts - p_vpar->synchro.backward_pts );
}
p_vpar->synchro.current_pts = p_vpar->synchro.backward_pts;
p_vpar->synchro.backward_pts = 0;
}
else if( p_vpar->sequence.next_dts )
{
if( p_vpar->sequence.next_dts - p_vpar->synchro.current_pts
> PTS_THRESHOLD
|| p_vpar->synchro.current_pts - p_vpar->sequence.next_dts
> PTS_THRESHOLD )
{
intf_WarnMsg( 2,
"vpar synchro warning: dts != current_pts (%lld)",
p_vpar->synchro.current_pts
- p_vpar->sequence.next_dts );
}
/* By definition of a DTS. */
p_vpar->synchro.current_pts = p_vpar->sequence.next_dts;
p_vpar->sequence.next_dts = 0;
}
if( p_vpar->sequence.next_pts )
{
/* Store the PTS for the next time we have to date an I picture. */
p_vpar->synchro.backward_pts = p_vpar->sequence.next_pts;
p_vpar->sequence.next_pts = 0;
}
}
#undef PTS_THRESHOLD
#if 0
/* Removed for incompatibility with slow motion */
if( p_vpar->synchro.current_pts + DEFAULT_PTS_DELAY < now )
{
/* We cannot be _that_ late, something must have happened, reinit
* the dates. */
intf_WarnMsg( 2, "PTS << now (%lld), resetting",
now - p_vpar->synchro.current_pts - DEFAULT_PTS_DELAY );
p_vpar->synchro.current_pts = now + DEFAULT_PTS_DELAY;
}
if( p_vpar->synchro.backward_pts
&& p_vpar->synchro.backward_pts + DEFAULT_PTS_DELAY < now )
{
/* The same. */
p_vpar->synchro.backward_pts = 0;
}
#endif
p_vpar->synchro.i_pic++;
}
/*****************************************************************************
* SynchroType: Get the user's synchro type
*****************************************************************************
* This function is called at initialization.
*****************************************************************************/
static int SynchroType( void )
{
char * psz_synchro = main_GetPszVariable( VPAR_SYNCHRO_VAR, NULL );
if( psz_synchro == NULL )
{
return VPAR_SYNCHRO_DEFAULT;
}
switch( *psz_synchro++ )
{
case 'i':
case 'I':
switch( *psz_synchro++ )
{
case '\0':
return VPAR_SYNCHRO_I;
case '+':
if( *psz_synchro ) return 0;
return VPAR_SYNCHRO_Iplus;
case 'p':
case 'P':
switch( *psz_synchro++ )
{
case '\0':
return VPAR_SYNCHRO_IP;
case '+':
if( *psz_synchro ) return 0;
return VPAR_SYNCHRO_IPplus;
case 'b':
case 'B':
if( *psz_synchro ) return 0;
return VPAR_SYNCHRO_IPB;
default:
return VPAR_SYNCHRO_DEFAULT;
}
default:
return VPAR_SYNCHRO_DEFAULT;
}
}
return VPAR_SYNCHRO_DEFAULT;
}