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vlc/modules/packetizer/mpegvideo.c

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/*****************************************************************************
* mpegvideo.c: parse and packetize an MPEG1/2 video stream
*****************************************************************************
* Copyright (C) 2001-2006 VLC authors and VideoLAN
* $Id$
*
* Authors: Laurent Aimar <fenrir@via.ecp.fr>
* Eric Petit <titer@videolan.org>
* Gildas Bazin <gbazin@videolan.org>
* Jean-Paul Saman <jpsaman #_at_# m2x dot nl>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* Problem with this implementation:
*
* Although we should time-stamp each picture with a PTS, this isn't possible
* with the current implementation.
* The problem comes from the fact that for non-low-delay streams we can't
* calculate the PTS of pictures used as backward reference. Even the temporal
* reference number doesn't help here because all the pictures don't
* necessarily have the same duration (eg. 3:2 pulldown).
*
* However this doesn't really matter as far as the MPEG muxers are concerned
* because they allow having empty PTS fields. --gibalou
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_block.h>
#include <vlc_codec.h>
#include <vlc_block_helper.h>
#include "../codec/cc.h"
#include "packetizer_helper.h"
#define SYNC_INTRAFRAME_TEXT N_("Sync on Intra Frame")
#define SYNC_INTRAFRAME_LONGTEXT N_("Normally the packetizer would " \
"sync on the next full frame. This flags instructs the packetizer " \
"to sync on the first Intra Frame found.")
/*****************************************************************************
* Module descriptor
*****************************************************************************/
static int Open ( vlc_object_t * );
static void Close( vlc_object_t * );
vlc_module_begin ()
set_category( CAT_SOUT )
set_subcategory( SUBCAT_SOUT_PACKETIZER )
set_description( N_("MPEG-I/II video packetizer") )
set_shortname( N_("MPEG Video") )
set_capability( "packetizer", 50 )
set_callbacks( Open, Close )
add_bool( "packetizer-mpegvideo-sync-iframe", false, SYNC_INTRAFRAME_TEXT,
SYNC_INTRAFRAME_LONGTEXT, true )
vlc_module_end ()
/*****************************************************************************
* Local prototypes
*****************************************************************************/
struct decoder_sys_t
{
/*
* Input properties
*/
packetizer_t packetizer;
/* Sequence header and extension */
block_t *p_seq;
block_t *p_ext;
/* Current frame being built */
block_t *p_frame;
block_t **pp_last;
bool b_frame_slice;
mtime_t i_pts;
mtime_t i_dts;
/* Sequence properties */
int i_frame_rate;
int i_frame_rate_base;
bool b_seq_progressive;
bool b_low_delay;
int i_aspect_ratio_info;
bool b_inited;
/* Picture properties */
int i_temporal_ref;
int i_picture_type;
int i_picture_structure;
int i_top_field_first;
int i_repeat_first_field;
int i_progressive_frame;
mtime_t i_interpolated_dts;
mtime_t i_last_ref_pts;
bool b_second_field;
/* Number of pictures since last sequence header */
int i_seq_old;
/* Sync behaviour */
bool b_sync_on_intra_frame;
bool b_discontinuity;
/* */
bool b_cc_reset;
uint32_t i_cc_flags;
mtime_t i_cc_pts;
mtime_t i_cc_dts;
cc_data_t cc;
};
static block_t *Packetize( decoder_t *, block_t ** );
static block_t *GetCc( decoder_t *p_dec, bool pb_present[4] );
static void PacketizeReset( void *p_private, bool b_broken );
static block_t *PacketizeParse( void *p_private, bool *pb_ts_used, block_t * );
static int PacketizeValidate( void *p_private, block_t * );
static block_t *ParseMPEGBlock( decoder_t *, block_t * );
static const uint8_t p_mp2v_startcode[3] = { 0x00, 0x00, 0x01 };
/*****************************************************************************
* Open:
*****************************************************************************/
static int Open( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t*)p_this;
decoder_sys_t *p_sys;
if( p_dec->fmt_in.i_codec != VLC_CODEC_MPGV )
return VLC_EGENERIC;
es_format_Init( &p_dec->fmt_out, VIDEO_ES, VLC_CODEC_MPGV );
p_dec->fmt_out.i_original_fourcc = p_dec->fmt_in.i_original_fourcc;
p_dec->pf_packetize = Packetize;
p_dec->pf_get_cc = GetCc;
p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
if( !p_dec->p_sys )
return VLC_ENOMEM;
memset( p_dec->p_sys, 0, sizeof( decoder_sys_t ) );
/* Misc init */
packetizer_Init( &p_sys->packetizer,
p_mp2v_startcode, sizeof(p_mp2v_startcode),
NULL, 0, 4,
PacketizeReset, PacketizeParse, PacketizeValidate, p_dec );
p_sys->p_seq = NULL;
p_sys->p_ext = NULL;
p_sys->p_frame = NULL;
p_sys->pp_last = &p_sys->p_frame;
p_sys->b_frame_slice = false;
p_sys->i_dts = p_sys->i_pts = VLC_TS_INVALID;
p_sys->i_frame_rate = 1;
p_sys->i_frame_rate_base = 1;
p_sys->b_seq_progressive = true;
p_sys->b_low_delay = true;
p_sys->i_seq_old = 0;
p_sys->i_temporal_ref = 0;
p_sys->i_picture_type = 0;
p_sys->i_picture_structure = 0x03; /* frame */
p_sys->i_top_field_first = 0;
p_sys->i_repeat_first_field = 0;
p_sys->i_progressive_frame = 0;
p_sys->b_inited = 0;
p_sys->i_interpolated_dts = VLC_TS_INVALID;
p_sys->i_last_ref_pts = VLC_TS_INVALID;
p_sys->b_second_field = 0;
p_sys->b_discontinuity = false;
p_sys->b_sync_on_intra_frame = var_CreateGetBool( p_dec, "packetizer-mpegvideo-sync-iframe" );
if( p_sys->b_sync_on_intra_frame )
msg_Dbg( p_dec, "syncing on intra frame now" );
p_sys->b_cc_reset = false;
p_sys->i_cc_pts = 0;
p_sys->i_cc_dts = 0;
p_sys->i_cc_flags = 0;
cc_Init( &p_sys->cc );
return VLC_SUCCESS;
}
/*****************************************************************************
* Close:
*****************************************************************************/
static void Close( vlc_object_t *p_this )
{
decoder_t *p_dec = (decoder_t*)p_this;
decoder_sys_t *p_sys = p_dec->p_sys;
if( p_sys->p_seq )
{
block_Release( p_sys->p_seq );
}
if( p_sys->p_ext )
{
block_Release( p_sys->p_ext );
}
if( p_sys->p_frame )
{
block_ChainRelease( p_sys->p_frame );
}
packetizer_Clean( &p_sys->packetizer );
var_Destroy( p_dec, "packetizer-mpegvideo-sync-iframe" );
free( p_sys );
}
/*****************************************************************************
* Packetize:
*****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
return packetizer_Packetize( &p_sys->packetizer, pp_block );
}
/*****************************************************************************
* GetCc:
*****************************************************************************/
static block_t *GetCc( decoder_t *p_dec, bool pb_present[4] )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_cc;
int i;
for( i = 0; i < 4; i++ )
pb_present[i] = p_sys->cc.pb_present[i];
if( p_sys->cc.i_data <= 0 )
return NULL;
p_cc = block_Alloc( p_sys->cc.i_data );
if( p_cc )
{
memcpy( p_cc->p_buffer, p_sys->cc.p_data, p_sys->cc.i_data );
p_cc->i_dts =
p_cc->i_pts = p_sys->cc.b_reorder ? p_sys->i_cc_pts : p_sys->i_cc_dts;
p_cc->i_flags = ( p_sys->cc.b_reorder ? p_sys->i_cc_flags : BLOCK_FLAG_TYPE_P ) & ( BLOCK_FLAG_TYPE_I|BLOCK_FLAG_TYPE_P|BLOCK_FLAG_TYPE_B);
}
cc_Flush( &p_sys->cc );
return p_cc;
}
/*****************************************************************************
* Helpers:
*****************************************************************************/
static void PacketizeReset( void *p_private, bool b_broken )
{
decoder_t *p_dec = p_private;
decoder_sys_t *p_sys = p_dec->p_sys;
if( b_broken )
{
p_sys->b_discontinuity = true;
if( p_sys->p_frame )
block_ChainRelease( p_sys->p_frame );
p_sys->p_frame = NULL;
p_sys->pp_last = &p_sys->p_frame;
p_sys->b_frame_slice = false;
}
p_sys->i_dts =
p_sys->i_pts =
p_sys->i_interpolated_dts =
p_sys->i_last_ref_pts = VLC_TS_INVALID;
}
static block_t *PacketizeParse( void *p_private, bool *pb_ts_used, block_t *p_block )
{
decoder_t *p_dec = p_private;
/* Check if we have a picture start code */
*pb_ts_used = p_block->p_buffer[3] == 0x00;
return ParseMPEGBlock( p_dec, p_block );
}
static int PacketizeValidate( void *p_private, block_t *p_au )
{
decoder_t *p_dec = p_private;
decoder_sys_t *p_sys = p_dec->p_sys;
/* If a discontinuity has been encountered, then wait till
* the next Intra frame before continuing with packetizing */
if( p_sys->b_discontinuity &&
p_sys->b_sync_on_intra_frame )
{
if( (p_au->i_flags & BLOCK_FLAG_TYPE_I) == 0 )
{
msg_Dbg( p_dec, "waiting on intra frame" );
return VLC_EGENERIC;
}
msg_Dbg( p_dec, "synced on intra frame" );
p_sys->b_discontinuity = false;
p_au->i_flags |= BLOCK_FLAG_DISCONTINUITY;
}
/* We've just started the stream, wait for the first PTS.
* We discard here so we can still get the sequence header. */
if( p_sys->i_dts <= VLC_TS_INVALID && p_sys->i_pts <= VLC_TS_INVALID &&
p_sys->i_interpolated_dts <= VLC_TS_INVALID )
{
msg_Dbg( p_dec, "need a starting pts/dts" );
return VLC_EGENERIC;
}
/* When starting the stream we can have the first frame with
* an invalid DTS (i_interpolated_pts is initialized to VLC_TS_INVALID) */
if( p_au->i_dts <= VLC_TS_INVALID )
p_au->i_dts = p_au->i_pts;
return VLC_SUCCESS;
}
/*****************************************************************************
* ParseMPEGBlock: Re-assemble fragments into a block containing a picture
*****************************************************************************/
static block_t *ParseMPEGBlock( decoder_t *p_dec, block_t *p_frag )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_pic = NULL;
/*
* Check if previous picture is finished
*/
if( ( p_sys->b_frame_slice &&
(p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) ) &&
p_sys->p_seq == NULL )
{
/* We have a picture but without a sequence header we can't
* do anything */
msg_Dbg( p_dec, "waiting for sequence start" );
if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
p_sys->p_frame = NULL;
p_sys->pp_last = &p_sys->p_frame;
p_sys->b_frame_slice = false;
}
else if( p_sys->b_frame_slice &&
(p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) )
{
const bool b_eos = p_frag->p_buffer[3] == 0xb7;
mtime_t i_duration;
if( b_eos )
{
block_ChainLastAppend( &p_sys->pp_last, p_frag );
p_frag = NULL;
}
p_pic = block_ChainGather( p_sys->p_frame );
if( b_eos )
p_pic->i_flags |= BLOCK_FLAG_END_OF_SEQUENCE;
i_duration = (mtime_t)( 1000000 * p_sys->i_frame_rate_base /
p_sys->i_frame_rate );
if( !p_sys->b_seq_progressive && p_sys->i_picture_structure != 0x03 )
{
i_duration /= 2;
}
if( p_sys->b_seq_progressive )
{
if( p_sys->i_top_field_first == 0 &&
p_sys->i_repeat_first_field == 1 )
{
i_duration *= 2;
}
else if( p_sys->i_top_field_first == 1 &&
p_sys->i_repeat_first_field == 1 )
{
i_duration *= 3;
}
}
else
{
if( p_sys->i_picture_structure == 0x03 )
{
if( p_sys->i_progressive_frame && p_sys->i_repeat_first_field )
{
i_duration += i_duration / 2;
}
}
}
if( p_sys->b_low_delay || p_sys->i_picture_type == 0x03 )
{
/* Trivial case (DTS == PTS) */
/* Correct interpolated dts when we receive a new pts/dts */
if( p_sys->i_pts > VLC_TS_INVALID )
p_sys->i_interpolated_dts = p_sys->i_pts;
if( p_sys->i_dts > VLC_TS_INVALID )
p_sys->i_interpolated_dts = p_sys->i_dts;
}
else
{
/* Correct interpolated dts when we receive a new pts/dts */
if(p_sys->i_last_ref_pts > VLC_TS_INVALID && !p_sys->b_second_field)
p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
if( p_sys->i_dts > VLC_TS_INVALID )
p_sys->i_interpolated_dts = p_sys->i_dts;
if( !p_sys->b_second_field )
p_sys->i_last_ref_pts = p_sys->i_pts;
}
p_pic->i_dts = p_sys->i_interpolated_dts;
p_sys->i_interpolated_dts += i_duration;
/* Set PTS only if we have a B frame or if it comes from the stream */
if( p_sys->i_pts > VLC_TS_INVALID )
{
p_pic->i_pts = p_sys->i_pts;
}
else if( p_sys->i_picture_type == 0x03 )
{
p_pic->i_pts = p_pic->i_dts;
}
else
{
p_pic->i_pts = VLC_TS_INVALID;
}
switch ( p_sys->i_picture_type )
{
case 0x01:
p_pic->i_flags |= BLOCK_FLAG_TYPE_I;
break;
case 0x02:
p_pic->i_flags |= BLOCK_FLAG_TYPE_P;
break;
case 0x03:
p_pic->i_flags |= BLOCK_FLAG_TYPE_B;
break;
}
p_pic->i_length = p_sys->i_interpolated_dts - p_pic->i_dts;
#if 0
msg_Dbg( p_dec, "pic: type=%d dts=%"PRId64" pts-dts=%"PRId64,
p_sys->i_picture_type, p_pic->i_dts, p_pic->i_pts - p_pic->i_dts);
#endif
/* Reset context */
p_sys->p_frame = NULL;
p_sys->pp_last = &p_sys->p_frame;
p_sys->b_frame_slice = false;
if( p_sys->i_picture_structure != 0x03 )
{
p_sys->b_second_field = !p_sys->b_second_field;
}
else
{
p_sys->b_second_field = 0;
}
/* CC */
p_sys->b_cc_reset = true;
p_sys->i_cc_pts = p_pic->i_pts;
p_sys->i_cc_dts = p_pic->i_dts;
p_sys->i_cc_flags = p_pic->i_flags;
}
if( !p_pic && p_sys->b_cc_reset )
{
p_sys->b_cc_reset = false;
cc_Flush( &p_sys->cc );
}
if( !p_frag )
return p_pic;
/*
* Check info of current fragment
*/
if( p_frag->p_buffer[3] == 0xb8 )
{
/* Group start code */
if( p_sys->p_seq &&
p_sys->i_seq_old > p_sys->i_frame_rate/p_sys->i_frame_rate_base )
{
/* Useful for mpeg1: repeat sequence header every second */
block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_seq ) );
if( p_sys->p_ext )
{
block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_ext ) );
}
p_sys->i_seq_old = 0;
}
}
else if( p_frag->p_buffer[3] == 0xb3 && p_frag->i_buffer >= 8 )
{
/* Sequence header code */
static const int code_to_frame_rate[16][2] =
{
{ 1, 1 }, /* invalid */
{ 24000, 1001 }, { 24, 1 }, { 25, 1 }, { 30000, 1001 },
{ 30, 1 }, { 50, 1 }, { 60000, 1001 }, { 60, 1 },
/* Unofficial 15fps from Xing*/
{ 15, 1001 },
/* Unofficial economy rates from libmpeg3 */
{ 5000, 1001 }, { 1000, 1001 }, { 12000, 1001 }, { 15000, 1001 },
{ 1, 1 }, { 1, 1 } /* invalid */
};
if( p_sys->p_seq ) block_Release( p_sys->p_seq );
if( p_sys->p_ext ) block_Release( p_sys->p_ext );
p_sys->p_seq = block_Duplicate( p_frag );
p_sys->i_seq_old = 0;
p_sys->p_ext = NULL;
p_dec->fmt_out.video.i_width =
( p_frag->p_buffer[4] << 4)|(p_frag->p_buffer[5] >> 4 );
p_dec->fmt_out.video.i_height =
( (p_frag->p_buffer[5]&0x0f) << 8 )|p_frag->p_buffer[6];
p_sys->i_aspect_ratio_info = p_frag->p_buffer[7] >> 4;
/* TODO: MPEG1 aspect ratio */
p_sys->i_frame_rate = code_to_frame_rate[p_frag->p_buffer[7]&0x0f][0];
p_sys->i_frame_rate_base =
code_to_frame_rate[p_frag->p_buffer[7]&0x0f][1];
p_dec->fmt_out.video.i_frame_rate = p_sys->i_frame_rate;
p_dec->fmt_out.video.i_frame_rate_base = p_sys->i_frame_rate_base;
p_sys->b_seq_progressive = true;
p_sys->b_low_delay = true;
if ( !p_sys->b_inited )
{
msg_Dbg( p_dec, "size %dx%d fps=%.3f",
p_dec->fmt_out.video.i_width, p_dec->fmt_out.video.i_height,
p_sys->i_frame_rate / (float)p_sys->i_frame_rate_base );
p_sys->b_inited = 1;
}
}
else if( p_frag->p_buffer[3] == 0xb5 )
{
int i_type = p_frag->p_buffer[4] >> 4;
/* Extension start code */
if( i_type == 0x01 )
{
#if 0
static const int mpeg2_aspect[16][2] =
{
{0,1}, {1,1}, {4,3}, {16,9}, {221,100},
{0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1},
{0,1}, {0,1}
};
#endif
/* sequence extension */
if( p_sys->p_ext) block_Release( p_sys->p_ext );
p_sys->p_ext = block_Duplicate( p_frag );
if( p_frag->i_buffer >= 10 )
{
p_sys->b_seq_progressive =
p_frag->p_buffer[5]&0x08 ? true : false;
p_sys->b_low_delay =
p_frag->p_buffer[9]&0x80 ? true : false;
}
/* Do not set aspect ratio : in case we're transcoding,
* transcode will take our fmt_out as a fmt_in to libmpeg2.
* libmpeg2.c will then believe that the user has requested
* a specific aspect ratio, which she hasn't. Thus in case
* of aspect ratio change, we're screwed. --Meuuh
*/
#if 0
p_dec->fmt_out.video.i_sar_num =
mpeg2_aspect[p_sys->i_aspect_ratio_info][0] *
p_dec->fmt_out.video.i_height;
p_dec->fmt_out.video.i_sar_den =
mpeg2_aspect[p_sys->i_aspect_ratio_info][1] *
p_dec->fmt_out.video.i_width;
#endif
}
else if( i_type == 0x08 )
{
/* picture extension */
p_sys->i_picture_structure = p_frag->p_buffer[6]&0x03;
p_sys->i_top_field_first = p_frag->p_buffer[7] >> 7;
p_sys->i_repeat_first_field= (p_frag->p_buffer[7]>>1)&0x01;
p_sys->i_progressive_frame = p_frag->p_buffer[8] >> 7;
}
}
else if( p_frag->p_buffer[3] == 0xb2 && p_frag->i_buffer > 4 )
{
cc_Extract( &p_sys->cc, p_sys->i_top_field_first,
&p_frag->p_buffer[4], p_frag->i_buffer - 4 );
}
else if( p_frag->p_buffer[3] == 0x00 )
{
/* Picture start code */
p_sys->i_seq_old++;
if( p_frag->i_buffer >= 6 )
{
p_sys->i_temporal_ref =
( p_frag->p_buffer[4] << 2 )|(p_frag->p_buffer[5] >> 6);
p_sys->i_picture_type = ( p_frag->p_buffer[5] >> 3 ) & 0x03;
}
p_sys->i_dts = p_frag->i_dts;
p_sys->i_pts = p_frag->i_pts;
}
else if( p_frag->p_buffer[3] >= 0x01 && p_frag->p_buffer[3] <= 0xaf )
{
/* Slice start code */
p_sys->b_frame_slice = true;
}
/* Append the block */
block_ChainLastAppend( &p_sys->pp_last, p_frag );
return p_pic;
}