void RegulateQ( CP_INSTANCE *cpi, ogg_int32_t UpdateScore ) {
double PredUnitScoreBytes;
ogg_uint32_t QIndex = Q_TABLE_SIZE - 1;
ogg_uint32_t i;
if ( UpdateScore > 0 ) {
double TargetUnitScoreBytes = (double)cpi->ThisFrameTargetBytes /
(double)UpdateScore;
double LastBitError = 10000.0; /* Silly high number */
/* Search for the best Q for the target bitrate. */
for ( i = 0; i < Q_TABLE_SIZE; i++ ) {
PredUnitScoreBytes = GetEstimatedBpb( cpi, cpi->pb.QThreshTable[i] );
if ( PredUnitScoreBytes > TargetUnitScoreBytes ) {
if ( (PredUnitScoreBytes - TargetUnitScoreBytes) <= LastBitError ) {
QIndex = i;
} else {
QIndex = i - 1;
}
break;
} else {
LastBitError = TargetUnitScoreBytes - PredUnitScoreBytes;
}
}
}
/* QIndex should now indicate the optimal Q. */
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[QIndex];
/* Apply range restrictions for key frames. */
if ( cpi->pb.FrameType == KEY_FRAME ) {
if ( cpi->pb.ThisFrameQualityValue > cpi->pb.QThreshTable[20] )
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[20];
else if ( cpi->pb.ThisFrameQualityValue < cpi->pb.QThreshTable[50] )
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[50];
}
/* Limit the Q value to the maximum available value */
if (cpi->pb.ThisFrameQualityValue >
cpi->pb.QThreshTable[cpi->Configuration.ActiveMaxQ]) {
cpi->pb.ThisFrameQualityValue =
(ogg_uint32_t)cpi->pb.QThreshTable[cpi->Configuration.ActiveMaxQ];
}
if(cpi->FixedQ) {
if ( cpi->pb.FrameType == KEY_FRAME ) {
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[43];
cpi->pb.ThisFrameQualityValue = cpi->FixedQ;
} else {
cpi->pb.ThisFrameQualityValue = cpi->FixedQ;
}
}
/* If the quantizer value has changed then re-initialise it */
if ( cpi->pb.ThisFrameQualityValue != cpi->pb.LastFrameQualityValue ) {
/* Initialise quality tables. */
UpdateQC( cpi, cpi->pb.ThisFrameQualityValue );
cpi->pb.LastFrameQualityValue = cpi->pb.ThisFrameQualityValue;
}
}
static void CompressFrame( CP_INSTANCE *cpi) {
ogg_int32_t min_blocks_per_frame;
ogg_uint32_t i;
int DropFrame = 0;
ogg_uint32_t ResidueBlocksAdded=0;
ogg_uint32_t KFIndicator = 0;
double QModStep;
double QModifier = 1.0;
/* Clear down the macro block level mode and MV arrays. */
for ( i = 0; i < cpi->pb.UnitFragments; i++ ) {
cpi->pb.FragCodingMethod[i] = CODE_INTER_NO_MV; /* Default coding mode */
cpi->pb.FragMVect[i].x = 0;
cpi->pb.FragMVect[i].y = 0;
}
/* Default to delta frames. */
SetFrameType( &cpi->pb, DELTA_FRAME );
/* Clear down the difference arrays for the current frame. */
memset( cpi->pb.display_fragments, 0, cpi->pb.UnitFragments );
memset( cpi->extra_fragments, 0, cpi->pb.UnitFragments );
/* Calculate the target bytes for this frame. */
cpi->ThisFrameTargetBytes = cpi->frame_target_rate;
/* Correct target to try and compensate for any overall rate error
that is developing */
/* Set the max allowed Q for this frame based upon carry over
history. First set baseline worst Q for this frame */
cpi->Configuration.ActiveMaxQ = cpi->Configuration.MaxQ + 10;
if ( cpi->Configuration.ActiveMaxQ >= Q_TABLE_SIZE )
cpi->Configuration.ActiveMaxQ = Q_TABLE_SIZE - 1;
/* Make a further adjustment based upon the carry over and recent
history.. cpi->Configuration.ActiveMaxQ reduced by 1 for each 1/2
seconds worth of -ve carry over up to a limit of 6. Also
cpi->Configuration.ActiveMaxQ reduced if frame is a
"DropFrameCandidate". Remember that if we are behind the bit
target carry over is -ve. */
if ( cpi->CarryOver < 0 ) {
if ( cpi->DropFrameCandidate ) {
cpi->Configuration.ActiveMaxQ -= 4;
}
if ( cpi->CarryOver <
-((ogg_int32_t)cpi->Configuration.TargetBandwidth*3) )
cpi->Configuration.ActiveMaxQ -= 6;
else
cpi->Configuration.ActiveMaxQ +=
(ogg_int32_t) ((cpi->CarryOver*2) /
(ogg_int32_t)cpi->Configuration.TargetBandwidth);
/* Check that we have not dropped quality too far */
if ( cpi->Configuration.ActiveMaxQ < cpi->Configuration.MaxQ )
cpi->Configuration.ActiveMaxQ = cpi->Configuration.MaxQ;
}
/* Calculate the Q Modifier step size required to cause a step down
from full target bandwidth to 40% of target between max Q and
best Q */
QModStep = 0.5 / (double)((Q_TABLE_SIZE - 1) -
cpi->Configuration.ActiveMaxQ);
/* Set up the cpi->QTargetModifier[] table. */
for ( i = 0; i < cpi->Configuration.ActiveMaxQ; i++ ) {
cpi->QTargetModifier[i] = QModifier;
}
for ( i = cpi->Configuration.ActiveMaxQ; i < Q_TABLE_SIZE; i++ ) {
cpi->QTargetModifier[i] = QModifier;
QModifier -= QModStep;
}
/* if we are allowed to drop frames and are falling behind (eg more
than x frames worth of bandwidth) */
if ( cpi->pb.info.dropframes_p &&
( cpi->DropCount < cpi->MaxConsDroppedFrames) &&
( cpi->CarryOver <
-((ogg_int32_t)cpi->Configuration.TargetBandwidth)) &&
( cpi->DropFrameCandidate) ) {
/* (we didn't do this frame so we should have some left over for
the next frame) */
cpi->CarryOver += cpi->frame_target_rate;
DropFrame = 1;
cpi->DropCount ++;
/* Adjust DropFrameTriggerBytes to account for the saving achieved. */
cpi->DropFrameTriggerBytes =
(cpi->DropFrameTriggerBytes *
(DF_CANDIDATE_WINDOW-1))/DF_CANDIDATE_WINDOW;
/* Even if we drop a frame we should account for it when
considering key frame seperation. */
cpi->LastKeyFrame++;
} else if ( cpi->CarryOver <
-((ogg_int32_t)cpi->Configuration.TargetBandwidth * 2) ) {
/* Reduce frame bit target by 1.75% for each 1/10th of a seconds
worth of -ve carry over down to a minimum of 65% of its
un-modified value. */
cpi->ThisFrameTargetBytes =
(ogg_uint32_t)(cpi->ThisFrameTargetBytes * 0.65);
} else if ( cpi->CarryOver < 0 ) {
/* Note that cpi->CarryOver is a -ve here hence 1.0 "+" ... */
cpi->ThisFrameTargetBytes =
(ogg_uint32_t)(cpi->ThisFrameTargetBytes *
(1.0 + ( ((cpi->CarryOver * 10)/
((ogg_int32_t)cpi->
Configuration.TargetBandwidth)) * 0.0175) ));
}
if ( !DropFrame ) {
/* pick all the macroblock modes and motion vectors */
ogg_uint32_t InterError;
ogg_uint32_t IntraError;
/* Set Baseline filter level. */
ConfigurePP( &cpi->pp, cpi->pb.info.noise_sensitivity);
/* Score / analyses the fragments. */
cpi->MotionScore = YUVAnalyseFrame(&cpi->pp, &KFIndicator );
/* Get the baseline Q value */
RegulateQ( cpi, cpi->MotionScore );
/* Recode blocks if the error score in last frame was high. */
ResidueBlocksAdded = 0;
for ( i = 0; i < cpi->pb.UnitFragments; i++ ){
if ( !cpi->pb.display_fragments[i] ){
if ( cpi->LastCodedErrorScore[i] >=
ResidueErrorThresh[cpi->pb.FrameQIndex] ) {
cpi->pb.display_fragments[i] = 1; /* Force block update */
cpi->extra_fragments[i] = 1; /* Insures up to date
pixel data is used. */
ResidueBlocksAdded ++;
}
}
}
/* Adjust the motion score to allow for residue blocks
added. These are assumed to have below average impact on
bitrate (Hence ResidueBlockFactor). */
cpi->MotionScore = cpi->MotionScore +
(ResidueBlocksAdded / ResidueBlockFactor[cpi->pb.FrameQIndex]);
/* Estimate the min number of blocks at best Q */
min_blocks_per_frame =
(ogg_int32_t)(cpi->ThisFrameTargetBytes /
GetEstimatedBpb( cpi, VERY_BEST_Q ));
if ( min_blocks_per_frame == 0 )
min_blocks_per_frame = 1;
/* If we have less than this number then consider adding in some
extra blocks */
if ( cpi->MotionScore < min_blocks_per_frame ) {
min_blocks_per_frame =
cpi->MotionScore +
(ogg_int32_t)(((min_blocks_per_frame - cpi->MotionScore) * 4) / 3 );
UpRegulateDataStream( cpi, VERY_BEST_Q, min_blocks_per_frame );
}else{
/* Reset control variable for best quality final pass. */
cpi->FinalPassLastPos = 0;
}
/* Get the modified Q prediction taking into account extra blocks added. */
RegulateQ( cpi, cpi->MotionScore );
/* Unless we are already well ahead (4 seconds of data) of the
projected bitrate */
if ( cpi->CarryOver <
(ogg_int32_t)(cpi->Configuration.TargetBandwidth * 4) ){
/* Look at the predicted Q (pbi->FrameQIndex). Adjust the
target bits for this frame based upon projected Q and
re-calculate. The idea is that if the Q is better than a
given (good enough) level then we will try and save some bits
for use in more difficult segments. */
cpi->ThisFrameTargetBytes =
(ogg_int32_t) (cpi->ThisFrameTargetBytes *
cpi->QTargetModifier[cpi->pb.FrameQIndex]);
/* Recalculate Q again */
RegulateQ( cpi, cpi->MotionScore );
}
/* Select modes and motion vectors for each of the blocks : return
an error score for inter and intra */
PickModes( cpi, cpi->pb.YSBRows, cpi->pb.YSBCols,
cpi->pb.info.width,
&InterError, &IntraError );
/* decide whether we really should have made this frame a key frame */
/* forcing out a keyframe if the max interval is up is done at a higher level */
if( cpi->pb.info.keyframe_auto_p){
if( ( 2* IntraError < 5 * InterError )
&& ( KFIndicator >= (ogg_uint32_t)
cpi->pb.info.keyframe_auto_threshold)
&& ( cpi->LastKeyFrame > cpi->pb.info.keyframe_mindistance)
){
CompressKeyFrame(cpi); /* Code a key frame */
return;
}
}
/* Increment the frames since last key frame count */
cpi->LastKeyFrame++;
/* Proceed with the frame update. */
UpdateFrame(cpi);
cpi->DropCount = 0;
if ( cpi->MotionScore > 0 ){
/* Note the Quantizer used for each block coded. */
for ( i = 0; i < cpi->pb.UnitFragments; i++ ){
if ( cpi->pb.display_fragments[i] ){
cpi->FragmentLastQ[i] = cpi->pb.ThisFrameQualityValue;
}
}
}
}else{
/* even if we 'drop' a frame, a placeholder must be written as we
currently assume fixed frame rate timebase as Ogg mapping
invariant */
UpdateFrame(cpi);
}
}
/****************************************************************************
*
* ROUTINE : RegulateQ
*
* INPUTS : INT32 BlocksToUpdate
*
* OUTPUTS : None.
*
* RETURNS : None.
*
* FUNCTION : If appropriate this function regulates the DCT
* coefficients to match the stream size to the
* available bandwidth (within defined limits).
*
* SPECIAL NOTES : None.
*
*
* ERRORS : None.
*
****************************************************************************/
void RegulateQ( CP_INSTANCE *cpi, INT32 UpdateScore )
{
double TargetUnitScoreBytes = (double)cpi->ThisFrameTargetBytes / (double)UpdateScore;
double PredUnitScoreBytes;
double LastBitError = 10000.0; // Silly high number
UINT32 QIndex = Q_TABLE_SIZE - 1;
UINT32 i;
// Search for the best Q for the target bitrate.
for ( i = 0; i < Q_TABLE_SIZE; i++ )
{
PredUnitScoreBytes = GetEstimatedBpb( cpi, cpi->pb.QThreshTable[i] );
if ( PredUnitScoreBytes > TargetUnitScoreBytes )
{
if ( (PredUnitScoreBytes - TargetUnitScoreBytes) <= LastBitError )
{
QIndex = i;
}
else
{
QIndex = i - 1;
}
break;
}
else
{
LastBitError = TargetUnitScoreBytes - PredUnitScoreBytes;
}
}
// QIndex should now indicate the optimal Q.
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[QIndex];
// Apply range restrictions for key frames.
if ( GetFrameType(&cpi->pb) == BASE_FRAME )
{
if ( cpi->pb.ThisFrameQualityValue > cpi->pb.QThreshTable[20] )
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[20];
else if ( cpi->pb.ThisFrameQualityValue < cpi->pb.QThreshTable[50] )
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[50];
}
// Limit the Q value to the maximum available value
if (cpi->pb.ThisFrameQualityValue > cpi->pb.QThreshTable[cpi->Configuration.ActiveMaxQ])
//if (cpi->pb.ThisFrameQualityValue > QThreshTable[cpi->Configuration.ActiveMaxQ])
{
cpi->pb.ThisFrameQualityValue = (UINT32)cpi->pb.QThreshTable[cpi->Configuration.ActiveMaxQ];
}
if(cpi->FixedQ)
{
if ( GetFrameType(&cpi->pb) == BASE_FRAME )
{
cpi->pb.ThisFrameQualityValue = cpi->pb.QThreshTable[43];
cpi->pb.ThisFrameQualityValue = cpi->FixedQ;
}
else
{
cpi->pb.ThisFrameQualityValue = cpi->FixedQ;
}
}
// If th quantiser value has changed then re-initialise it
if ( cpi->pb.ThisFrameQualityValue != cpi->pb.LastFrameQualityValue )
{
/* Initialise quality tables. */
UpdateQC( cpi, cpi->pb.ThisFrameQualityValue );
cpi->pb.LastFrameQualityValue = cpi->pb.ThisFrameQualityValue;
}
}