/****************************************************************************
* Packetize: the whole thing
* Search for the startcodes 3 or more bytes
* Feed ParseNALBlock ALWAYS with 4 byte startcode prepended NALs
****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_pic;
if( !pp_block || !*pp_block ) return NULL;
block_BytestreamPush( &p_sys->bytestream, *pp_block );
for( ;; )
{
switch( p_sys->i_state )
{
case STATE_NOSYNC:
/* Skip until 3 byte startcode 0 0 1 */
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
{
p_sys->i_state = STATE_NEXT_SYNC;
}
if( p_sys->i_offset )
{
/* skip the data */
block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
p_sys->i_offset = 0;
block_BytestreamFlush( &p_sys->bytestream );
}
if( p_sys->i_state != STATE_NEXT_SYNC )
{
/* Need more data */
return NULL;
}
p_sys->i_offset = 1; /* To find next startcode */
case STATE_NEXT_SYNC:
/* Find the next 3 byte startcode 0 0 1*/
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->startcode+1, 3 ) != VLC_SUCCESS)
{
/* Need more data */
return NULL;
}
/* Get the new fragment and set the pts/dts */
p_pic = block_New( p_dec, p_sys->i_offset +1 );
p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
/* Force 4 byte startcode 0 0 0 1 */
p_pic->p_buffer[0] = 0;
block_GetBytes( &p_sys->bytestream, &p_pic->p_buffer[1],
p_pic->i_buffer-1 );
/* Remove trailing 0 bytes */
while( p_pic->i_buffer && (!p_pic->p_buffer[p_pic->i_buffer-1] ) )
p_pic->i_buffer--;
p_sys->i_offset = 0;
/* Parse the NAL */
if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
{
p_sys->i_state = STATE_NOSYNC;
break;
}
#if 0
msg_Dbg( p_dec, "pts="I64Fd" dts="I64Fd,
p_pic->i_pts, p_pic->i_dts );
#endif
/* So p_block doesn't get re-added several times */
*pp_block = block_BytestreamPop( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
return p_pic;
}
}
}
/*****************************************************************************
* Packetize:
*****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_pic;
if( pp_block == NULL || *pp_block == NULL )
{
return NULL;
}
if( (*pp_block)->i_flags & BLOCK_FLAG_DISCONTINUITY )
{
p_sys->i_state = STATE_NOSYNC;
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 = VLC_FALSE;
block_Release( *pp_block );
return NULL;
}
block_BytestreamPush( &p_sys->bytestream, *pp_block );
while( 1 )
{
switch( p_sys->i_state )
{
case STATE_NOSYNC:
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->p_startcode, 3 ) == VLC_SUCCESS )
{
p_sys->i_state = STATE_NEXT_SYNC;
}
if( p_sys->i_offset )
{
block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
p_sys->i_offset = 0;
block_BytestreamFlush( &p_sys->bytestream );
}
if( p_sys->i_state != STATE_NEXT_SYNC )
{
/* Need more data */
return NULL;
}
p_sys->i_offset = 1; /* To find next startcode */
case STATE_NEXT_SYNC:
/* TODO: If p_block == NULL, flush the buffer without checking the
* next sync word */
/* Find the next startcode */
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->p_startcode, 3 ) != VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
/* Get the new fragment and set the pts/dts */
p_pic = block_New( p_dec, p_sys->i_offset );
block_BytestreamFlush( &p_sys->bytestream );
p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
p_pic->i_buffer );
/* don't reuse the same timestamps several times */
if( p_pic->i_buffer >= 4 && p_pic->p_buffer[3] == 0x00 )
{
/* We have a picture start code */
p_sys->bytestream.p_block->i_pts = 0;
p_sys->bytestream.p_block->i_dts = 0;
}
p_sys->i_offset = 0;
/* Get picture if any */
if( !( p_pic = ParseMPEGBlock( p_dec, p_pic ) ) )
{
p_sys->i_state = STATE_NOSYNC;
break;
}
/* 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 <= 0 && p_sys->i_pts <= 0 &&
p_sys->i_interpolated_dts <= 0 )
{
msg_Dbg( p_dec, "need a starting pts/dts" );
p_sys->i_state = STATE_NOSYNC;
block_Release( p_pic );
break;
}
/* When starting the stream we can have the first frame with
* a null DTS (i_interpolated_pts is initialized to 0) */
if( !p_pic->i_dts ) p_pic->i_dts = p_pic->i_pts;
/* So p_block doesn't get re-added several times */
*pp_block = block_BytestreamPop( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
return p_pic;
}
}
}
/***
* Bytestream synchronizer
* maps [Bytes] -> DataUnit
*/
static block_t *dirac_DoSync( decoder_t *p_dec )
{
decoder_sys_t *p_sys = p_dec->p_sys;
parse_info_t pu;
static const uint8_t p_parsecode[4] = {'B','B','C','D'};
do {
switch( p_sys->i_state )
{
case NOT_SYNCED:
{
if( VLC_SUCCESS !=
block_FindStartcodeFromOffset( &p_sys->bytestream, &p_sys->i_offset, p_parsecode, 4 ) )
{
/* p_sys->i_offset will have been set to:
* end of bytestream - amount of prefix found
* can resume search from this point when more data arrives */
return NULL;
}
/* candidate parse_code_prefix has been found at p_sys->i_offset */
if( VLC_SUCCESS != block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_offset + 12, NULL, 0 ) )
{
/* insufficient data has been accumulated to fully extract
* a parse_info header. exit for now in the hope of more
* data later to retry at exactly the same point */
return NULL;
}
p_sys->i_state = TRY_SYNC;
break; /* candidate found, try to sync */
}
case SYNCED: /* -> TRY_SYNC | NOT_SYNCED */
/* sanity: can only reach this after having extracted a DU,
* which causes data to be consumed and local i_offset to be reset */
assert( p_sys->i_offset == 0 );
if( VLC_SUCCESS != block_PeekOffsetBytes( &p_sys->bytestream, 12, NULL, 0 ) )
{
/* insufficient data has been accumulated to fully extract
* a parse_info header, retry later */
return NULL;
}
if( !dirac_UnpackParseInfo( &pu, &p_sys->bytestream, 0 )
|| !pu.u_next_offset || (p_sys->u_last_npo != pu.u_prev_offset) )
{
/* !a: not a valid parse info.
* !pu.u_next_offset: don't know the length of the data unit
* search for the next one that points back
* to this one to determine length.
* (p_sys->u_last_npo != pu.u_prev_offset): some desync
*/
p_sys->i_state = NOT_SYNCED;
break;
}
if( pu.u_next_offset > 1024*1024 )
{
/* sanity check for erronious hugs next_parse_offsets
* (eg, 2^32-1) that would cause a very long wait
* and large space consumption: fall back to try sync */
p_sys->i_state = TRY_SYNC;
break;
}
/* check that the start of the next data unit is avaliable */
if( VLC_SUCCESS !=
block_PeekOffsetBytes( &p_sys->bytestream, pu.u_next_offset + 12, NULL, 0 ) )
{
return NULL; /* retry later */
}
/* attempt to synchronise backwards from pu.u_next_offset */
p_sys->i_offset = pu.u_next_offset;
/* fall through */
case TRY_SYNC: /* -> SYNCED | NOT_SYNCED */
{
if( !p_sys->i_offset )
goto sync_fail; /* if a is at start of bytestream, b can't be in buffer */
parse_info_t pu_a;
bool a = dirac_UnpackParseInfo( &pu_a, &p_sys->bytestream, p_sys->i_offset );
if( !a || (pu_a.u_prev_offset > p_sys->i_offset) )
goto sync_fail; /* b lies beyond start of bytestream: can't sync */
if( !pu_a.u_prev_offset )
{
if( p_sys->i_state == TRY_SYNC )
{
goto sync_fail; /* can't find different pu_b from pu_a */
}
/* state == SYNCED: already know where pu_b is.
* pu_a has probably been inserted by something that doesn't
* know what the last next_parse_offset was */
pu_a.u_prev_offset = pu.u_next_offset;
}
parse_info_t *pu_b = &pu;
bool b = dirac_UnpackParseInfo( pu_b, &p_sys->bytestream, p_sys->i_offset - pu_a.u_prev_offset );
if( !b || (pu_b->u_next_offset && pu_a.u_prev_offset != pu_b->u_next_offset) )
{
/* if pu_b->u_next_offset = 0, have to assume we've synced, ie,
* just rely on finding a valid pu_b from pu_a. */
goto sync_fail;
}
p_sys->u_last_npo = pu_b->u_next_offset;
if( !pu_b->u_next_offset ) pu_b->u_next_offset = pu_a.u_prev_offset;
/* offset was pointing at pu_a, rewind to point at pu_b */
p_sys->i_offset -= pu_a.u_prev_offset;
p_sys->i_state = SYNCED;
break;
}
sync_fail:
if( p_sys->i_state == SYNCED ) p_sys->i_offset = 0;
p_sys->i_offset++;
p_sys->i_state = NOT_SYNCED;
break; /* find somewhere else to try again */
default:;
}
} while( SYNCED != p_sys->i_state );
/*
* synced, attempt to extract a data unit
*/
/* recover any timestamps from the data that is about to be flushed */
dirac_RecoverTimestamps( p_dec, p_sys->i_offset );
/* flush everything up to the start of the DU */
block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
block_BytestreamFlush( &p_sys->bytestream );
p_sys->i_offset = 0;
/* setup the data unit buffer */
block_t *p_block = block_Alloc( pu.u_next_offset );
if( !p_block )
return NULL;
p_block->i_pts = p_sys->i_sync_pts;
p_block->i_dts = p_sys->i_sync_dts;
p_sys->i_sync_pts = p_sys->i_sync_dts = VLC_TS_INVALID;
/* recover any new timestamps from the data that is about to be consumed */
dirac_RecoverTimestamps( p_dec, p_sys->i_offset );
block_GetBytes( &p_sys->bytestream, p_block->p_buffer, p_block->i_buffer );
/* save parse offset in private area for later use */
dirac_block_encap_t *p_dbe = dirac_NewBlockEncap( &p_block );
if( p_dbe ) p_dbe->u_last_next_offset = pu.u_next_offset;
return p_block;
}
/****************************************************************************
* Packetize: the whole thing
****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_pic;
if( !pp_block || !*pp_block ) return NULL;
block_BytestreamPush( &p_sys->bytestream, *pp_block );
for( ;; )
{
switch( p_sys->i_state )
{
case STATE_NOSYNC:
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
{
p_sys->i_state = STATE_NEXT_SYNC;
}
if( p_sys->i_offset )
{
block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
p_sys->i_offset = 0;
block_BytestreamFlush( &p_sys->bytestream );
}
if( p_sys->i_state != STATE_NEXT_SYNC )
{
/* Need more data */
return NULL;
}
p_sys->i_offset = 1; /* To find next startcode */
case STATE_NEXT_SYNC:
/* Find the next startcode */
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->startcode, 3 ) != VLC_SUCCESS)
{
if( block_FindStartcodeFromOffset( &p_sys->bytestream,
&p_sys->i_offset, p_sys->startcode+1, 3 ) !=
VLC_SUCCESS )
{
/* Need more data */
return NULL;
}
}
/* Get the new fragment and set the pts/dts */
p_pic = block_New( p_dec, p_sys->i_offset );
p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
p_pic->i_buffer );
p_sys->i_offset = 0;
/* Parse the NAL */
if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
{
p_sys->i_state = STATE_NOSYNC;
break;
}
/* So p_block doesn't get re-added several times */
*pp_block = block_BytestreamPop( &p_sys->bytestream );
p_sys->i_state = STATE_NOSYNC;
return p_pic;
}
}
}
