H.264 B-frames in IPNC 3.5

The first mystery seems to be solved.  The encoder is using open GOPs, so the first B-frame of a GOP is predicted from a reference frame in the previous GOP.  That first B-frame is missing from the first GOP because there's no previous GOP from which to predict it.  However, I'm still confused about why the encoded file size goes up and the PSNR goes down when I enable B-frames.

Dave Beal,

Could you please share the encoder configurations used here? ~5db PSNR deviation is too much, there should be something fishy in parameter settings or buffer handling.

Also mention the video encoder release integrated to this application. 

Thanks.

Hello  Santosh -

Thanks in advance for your help!

The encoder is REL.500.V.H264AVC.E.IVAHD.02.00.04.01.

Here are my encoder params:

        inter = 1;    // or 2 for B-frames

        encPrm.chCreateParams[0].defaultDynamicParams.inputFrameRate = 30;
        encPrm.chCreateParams[0].defaultDynamicParams.intraFrameInterval = 16;
        encPrm.chCreateParams[0].defaultDynamicParams.targetBitRate = 3000000;
        encPrm.chCreateParams[0].format =IVIDEO_H264HP ;
        encPrm.chCreateParams[0].profile                 = VENC_CHN_HIGH_PROFILE;
        encPrm.chCreateParams[0].dataLayout              = IVIDEO_PROGRESSIVE;
        encPrm.chCreateParams[0].fieldMergeEncodeEnable  = FALSE;
        encPrm.chCreateParams[0].enableAnalyticinfo      = FALSE;
        encPrm.chCreateParams[0].maxBitRate              = 6000000;
        encPrm.chCreateParams[0].encodingPreset          = XDM_DEFAULT;
        encPrm.chCreateParams[0].rateControlPreset       = IVIDEO_USER_DEFINED;
        encPrm.chCreateParams[0].enableHighSpeed         = FALSE;
        encPrm.chCreateParams[0].enableWaterMarking      = FALSE;

        rateCntrlTi = VENC_RATE_CTRL_CBR;
        if (inter > 1) {
            rateCntrlTi = VENC_RATE_CTRL_VBR;  // Can't do low delay RC if B frames enabled???
            encPrm.chCreateParams[0].StreamPreset = ALG_VID_ENC_PRESET_HIGHQUALITY;
        } else {
            encPrm.chCreateParams[0].StreamPreset = ALG_VID_ENC_PRESET_AUTO;
        }
        encPrm.chCreateParams[0].enableAnalyticinfo = 0;
        encPrm.chCreateParams[0].defaultDynamicParams.interFrameInterval = inter;
        encPrm.chCreateParams[0].defaultDynamicParams.mvAccuracy = IVIDENC2_MOTIONVECTOR_QUARTERPEL;
        encPrm.chCreateParams[0].defaultDynamicParams.rcAlg            = rateCntrlTi;
        encPrm.chCreateParams[0].defaultDynamicParams.qpMin            = 5;
        encPrm.chCreateParams[0].defaultDynamicParams.qpMax            = 50;
        encPrm.chCreateParams[0].defaultDynamicParams.qpInit           = -1;
        encPrm.chCreateParams[0].defaultDynamicParams.vbrDuration      = 8;
        encPrm.chCreateParams[0].defaultDynamicParams.vbrSensitivity   = 0;
        encPrm.numBufPerCh[0] = 30;
        encPrm.numFullBufPerCh[0] = 3;
        encPrm.bufBytesPerCh[0] = 2250000;

For a 739-frame YUV stream of 1920x1080, I get these encoded file sizes and PSNR values:

interframeInterval = 1, CBR:  4,659,759 bytes, 26.30 dB

interframeInterval = 1, VBR: 5,648,671 bytes, 27.00 dB

interframeInterval = 2, VBR: 10,007,368 bytes, 20.87 dB

The YUV file is about 2.3GB.  If you need it, I'll try compressing it.

One more fact that seems to explain the size difference between encoded files containing B-frames and those that don't:  At the beginning of the encoded files that contain B-frames, the B-frames are approximately the same size as the P-frames (both about 5500 bytes) .  However, the B-frames quickly become bigger.  By the end of the 739 frame sequence, the B-frames are at least 4 times bigger than the P-frames (22000 byte B-frames vs. 4600 byte P-frames).

Dave Beal,

Okay, H.264 encoder release 02.00.04.01 supports encoding 'B' Frames. 

The encoder settings you have shared are not the complete set, with only these parameters(shared) we will not be able test at our end. I hope full set of encoder parameters are programmed somewhere down the layer at application side. We basically need all those parameters. Alternatively, encoder parameters set can be known by doing an encoder control call for XDM_GETSTATUS. Please do this exercise and share full set of parameters.

As of now we  don't  need raw video content, so don't share .

FYI,  Sample Encoder settings to enable 'B' frames are as follows,

STATIC/CREATE:

((gCodecParams).codec_params).params = {...}
videnc2Params = {...}
size = 0x00000138
encodingPreset = 0x00000003
rateControlPreset = 0x00000005
maxHeight = 0x00000438
maxWidth = 0x00000780
dataEndianness = 0x00000001
maxInterFrameInterval = 0x00000002
maxBitRate = 0xFFFFFFC0
minBitRate = 256000
inputChromaFormat = 0x00000009
inputContentType = 0x00000000
operatingMode = 0x00000001
profile = 0x00000064
level = 0x00000029
inputDataMode = 0x00000003
outputDataMode = 0x00000003
numInputDataUnits = 0x00000001
numOutputDataUnits = 0x00000001
metadataType = 0x00400BAC
[0] = 0x00000100
[1] = 0xFFFFFFFF
[2] = 0xFFFFFFFF
rateControlParams = {...}
rateControlParamsPreset = 0x01
scalingMatrixPreset = 0x02
rcAlgo = 0x00
qpI = 0x1E
qpMaxI = 0x29
qpMinI = 0x14
qpP = 0x1E
qpMaxP = 0x29
qpMinP = 0x14
qpOffsetB = 0x04
qpMaxB = 0x29
qpMinB = 0x14
allowFrameSkip = 0x00
removeExpensiveCoeff = 0x00
chromaQPIndexOffset = 0x00
IPQualityFactor = 0x00
initialBufferLevel = 0x002FAF08
HRDBufferSize = 0x017D7840
minPicSizeRatioI = 0x0000
maxPicSizeRatioI = 0x0000
minPicSizeRatioP = 0x0000
maxPicSizeRatioP = 0x0000
minPicSizeRatioB = 0x0000
maxPicSizeRatioB = 0x0000
enablePRC = 0x01
enablePartialFrameSkip = 0x01
discardSavedBits = 0x00
reserved = 0x00
VBRDuration = 0x00000008
VBRsensitivity = 0x00
skipDistributionWindowLength = 0x0000
numSkipInDistributionWindow = 0x0000
enableHRDComplianceMode = 0x01
frameSkipThMulQ5 = 0x00000000
vbvUseLevelThQ5 = 0x00000000
reservedRC = 0x00400BF4
[0] = 0x00000000
[1] = 0x00000000
[2] = 0x00000000
interCodingParams = {...}
interCodingPreset = 0x01
searchRangeHorP = 0x0090
searchRangeVerP = 0x0020
searchRangeHorB = 0x0090
searchRangeVerB = 0x0010
interCodingBias = 0x01
skipMVCodingBias = 0x01
minBlockSizeP = 0x00
minBlockSizeB = 0x00
meAlgoMode = 0x00
intraCodingParams = {...}
intraCodingPreset = 0x01
lumaIntra4x4Enable = 0x0000
lumaIntra8x8Enable = 0x00FF
lumaIntra16x16Enable = 0x0F
chromaIntra8x8Enable = 0x0F
chromaComponentEnable = 0x01
intraRefreshMethod = 0x00
intraRefreshRate = 0x0000
gdrOverlapRowsBtwFrames = 0x0000
constrainedIntraPredEnable = 0x0000
intraCodingBias = 0x00
nalUnitControlParams = {...}
naluControlPreset = 0x0001
naluPresentMaskStartOfSequence = 0x63C0
naluPresentMaskIDRPicture = 0x4240
naluPresentMaskIntraPicture = 0x4240
naluPresentMaskNonIntraPicture = 0x4240
naluPresentMaskEndOfSequence = 0x4E40
sliceCodingParams = {...}
sliceCodingPreset = 0x00
sliceMode = 0x0000
sliceUnitSize = 0x0000
sliceStartOffset = 0x00400C34
[0] = 0x00
[1] = 0x00
[2] = 0x00
streamFormat = 0x00
loopFilterParams = {...}
loopfilterPreset = 0x01
loopfilterDisableIDC = 0x00
filterOffsetA = 0x00
filterOffsetB = 0x00
fmoCodingParams = {...}
fmoCodingPreset = 0x00
numSliceGroups = 0x01
sliceGroupMapType = 0x04
sliceGroupChangeDirectionFlag = 0x00
sliceGroupChangeRate = 0x00
sliceGroupChangeCycle = 0x0000
sliceGroupParams = 0x00400C44
[0] = 0x0000
[1] = 0x0000
vuiCodingParams = {...}
vuiCodingPreset = 0x01
aspectRatioInfoPresentFlag = 0x01
aspectRatioIdc = 0x01
videoSignalTypePresentFlag = 0x00
videoFormat = 0x02
videoFullRangeFlag = 0x01
timingInfoPresentFlag = 0x01
hrdParamsPresentFlag = 0x01
numUnitsInTicks = 0x000003E8
stereoInfoParams = {...}
stereoInfoPreset = 0x00
topFieldIsLeftViewFlag = 0x00
viewSelfContainedFlag = 0x00
framePackingSEIParams = {...}
framePackingPreset = 0x00
framePackingType = 0x00
frame0PositionX = 0x00
frame0PositionY = 0x00
frame1PositionX = 0x00
frame1PositionY = 0x00
reservedByte = 0x00
svcCodingParams = {...}
svcExtensionFlag = 0x00
dependencyID = 0x00
qualityID = 0x00
enhancementProfileID = 0x00
layerIndex = 0x00
refLayerDQId = 0x00
interlaceCodingType = 0x03
bottomFieldIntra = 0x00
gopStructure = 0x01
entropyCodingMode = 0x01
transformBlockSize = 0x02
log2MaxFNumMinus4 = 0x08
picOrderCountType = 0x01
enableWatermark = 0x00
IDRFrameInterval = 0x00000001
pConstantMemory = 0x00000000
maxIntraFrameInterval = 0x00000010
debugTraceLevel = 0x00000001
lastNFramesToLog = 0x00000000
enableAnalyticinfo = 0x00
enableGMVSei = 0x00
constraintSetFlags = 0x00
enableRCDO = 0x00
enableLongTermRefFrame = 0x00000000
LTRPPeriod = 0xFFFFFFFF
numTemporalLayer = 0x01
referencePicMarking = 0x01
reservedParams = 0x00400C90
[0] = 0x00000000
[1] = 0x0000001F
[2] = 0x00000000

DYNAMIC:

((gCodecParams).codec_params).dynamicParams = {...}
videnc2DynamicParams = {...}
size = 0x000000EC
inputHeight = 0x00000438
inputWidth = 0x00000780
refFrameRate = 0x00007530
targetFrameRate = 0x00007530
targetBitRate = 0x017D7840
intraFrameInterval = 0x00000010
generateHeader = 0x00000000
captureWidth = 0x00000780
forceFrame = 0xFFFFFFFF
interFrameInterval = 0x00000002
mvAccuracy = 0x00000002
sampleAspectRatioHeight = 0x00000001
sampleAspectRatioWidth = 0x00000001
ignoreOutbufSizeFlag = 0x00000001
putDataFxn = 0x9FDC6A39
putDataHandle = 0x00000000
getDataFxn = 0x9FDC7715
getDataHandle = 0x9FD9B628
getBufferFxn = 0x9FDC618D
getBufferHandle = 0x00000000
lateAcquireArg = 0x00000100
rateControlParams = {...}
rateControlParamsPreset = 0x01
scalingMatrixPreset = 0x02
rcAlgo = 0x00
qpI = 0x1E
qpMaxI = 0x29
qpMinI = 0x14
qpP = 0x1E
qpMaxP = 0x29
qpMinP = 0x14
qpOffsetB = 0x04
qpMaxB = 0x29
qpMinB = 0x14
allowFrameSkip = 0x00
removeExpensiveCoeff = 0x00
chromaQPIndexOffset = 0x00
IPQualityFactor = 0x00
initialBufferLevel = 0x002FAF08
HRDBufferSize = 0x017D7840
minPicSizeRatioI = 0x0000
maxPicSizeRatioI = 0x0000
minPicSizeRatioP = 0x0000
maxPicSizeRatioP = 0x0000
minPicSizeRatioB = 0x0000
maxPicSizeRatioB = 0x0000
enablePRC = 0x01
enablePartialFrameSkip = 0x01
discardSavedBits = 0x00
reserved = 0x00
VBRDuration = 0x00000008
VBRsensitivity = 0x00
skipDistributionWindowLength = 0x0000
numSkipInDistributionWindow = 0x0000
enableHRDComplianceMode = 0x01
frameSkipThMulQ5 = 0x00000000
vbvUseLevelThQ5 = 0x00000000
reservedRC = 0x00400D30
[0] = 0x00000000
[1] = 0x00000000
[2] = 0x00000000
interCodingParams = {...}
interCodingPreset = 0x01
searchRangeHorP = 0x0090
searchRangeVerP = 0x0020
searchRangeHorB = 0x0090
searchRangeVerB = 0x0010
interCodingBias = 0x01
skipMVCodingBias = 0x01
minBlockSizeP = 0x00
minBlockSizeB = 0x00
meAlgoMode = 0x00
intraCodingParams = {...}
intraCodingPreset = 0x01
lumaIntra4x4Enable = 0x0000
lumaIntra8x8Enable = 0x00FF
lumaIntra16x16Enable = 0x0F
chromaIntra8x8Enable = 0x0F
chromaComponentEnable = 0x01
intraRefreshMethod = 0x00
intraRefreshRate = 0x0000
gdrOverlapRowsBtwFrames = 0x0000
constrainedIntraPredEnable = 0x0000
intraCodingBias = 0x00
sliceCodingParams = {...}
sliceCodingPreset = 0x00
sliceMode = 0x0000
sliceUnitSize = 0x0000
sliceStartOffset = 0x00400D64
[0] = 0x00
[1] = 0x00
[2] = 0x00
streamFormat = 0x00
sliceGroupChangeCycle = 0x00000000
searchCenter = {...}
x = 0x00007FFF
y = 0x00007FFF
enableStaticMBCount = 0x00
enableROI = 0x00000000
reservedDynParams = 0x00400D7C
[0] = 0x6942676E
[1] = 0x3D007361
[2] = 0x6D003100

Thanks.

Encoder output with the above settings and bits consumed for respective frame types are as expected.

Frame No // Frame Type// Bits

#0 : IVIDEO_NA_FRAME : Bits : 0
#1 : IVIDEO_IDR_FRAME : Bits : 536072
#2 : IVIDEO_B_FRAME : Bits : 93584
#3 : IVIDEO_P_FRAME : Bits : 32832
#4 : IVIDEO_B_FRAME : Bits : 11928
#5 : IVIDEO_P_FRAME : Bits : 51392
#6 : IVIDEO_B_FRAME : Bits : 17864
#7 : IVIDEO_P_FRAME : Bits : 47216
#8 : IVIDEO_B_FRAME : Bits : 12856
#9 : IVIDEO_P_FRAME : Bits : 42520
#10 : IVIDEO_B_FRAME : Bits : 11560
#11 : IVIDEO_P_FRAME : Bits : 49608
#12 : IVIDEO_B_FRAME : Bits : 13800
#13 : IVIDEO_P_FRAME : Bits : 45336
#14 : IVIDEO_B_FRAME : Bits : 15880
#15 : IVIDEO_P_FRAME : Bits : 43352
#16 : IVIDEO_B_FRAME : Bits : 31224
#17 : IVIDEO_IDR_FRAME : Bits : 345384
#18 : IVIDEO_B_FRAME : Bits : 31104
#19 : IVIDEO_P_FRAME : Bits : 75176
#20 : IVIDEO_B_FRAME : Bits : 29384
#21 : IVIDEO_P_FRAME : Bits : 111024
#22 : IVIDEO_B_FRAME : Bits : 35656
#23 : IVIDEO_P_FRAME : Bits : 130648
#24 : IVIDEO_B_FRAME : Bits : 52640
#25 : IVIDEO_P_FRAME : Bits : 167264
#26 : IVIDEO_B_FRAME : Bits : 85768
#27 : IVIDEO_P_FRAME : Bits : 195096
#28 : IVIDEO_B_FRAME : Bits : 92088
#29 : IVIDEO_P_FRAME : Bits : 232800
#30 : IVIDEO_B_FRAME : Bits : 110888
#31 : IVIDEO_P_FRAME : Bits : 233168
#32 : IVIDEO_B_FRAME : Bits : 125136
#33 : IVIDEO_IDR_FRAME : Bits : 485192
#34 : IVIDEO_B_FRAME : Bits : 140432
#35 : IVIDEO_P_FRAME : Bits : 219384
#36 : IVIDEO_B_FRAME : Bits : 111312
#37 : IVIDEO_P_FRAME : Bits : 203648
#38 : IVIDEO_B_FRAME : Bits : 111712
#39 : IVIDEO_P_FRAME : Bits : 216208
#40 : IVIDEO_B_FRAME : Bits : 102360
#41 : IVIDEO_P_FRAME : Bits : 214224
#42 : IVIDEO_B_FRAME : Bits : 96480
#43 : IVIDEO_P_FRAME : Bits : 204312
#44 : IVIDEO_B_FRAME : Bits : 102672
#45 : IVIDEO_P_FRAME : Bits : 223064
#46 : IVIDEO_B_FRAME : Bits : 109072
#47 : IVIDEO_P_FRAME : Bits : 203912
#48 : IVIDEO_B_FRAME : Bits : 89360
#49 : IVIDEO_IDR_FRAME : Bits : 518504
#50 : IVIDEO_B_FRAME : Bits : 107064
#51 : IVIDEO_P_FRAME : Bits : 145448
#52 : IVIDEO_B_FRAME : Bits : 75592
#53 : IVIDEO_P_FRAME : Bits : 179056
#54 : IVIDEO_B_FRAME : Bits : 76896
#55 : IVIDEO_P_FRAME : Bits : 196920
#56 : IVIDEO_B_FRAME : Bits : 118472
#57 : IVIDEO_P_FRAME : Bits : 216872
#58 : IVIDEO_B_FRAME : Bits : 102768
#59 : IVIDEO_P_FRAME : Bits : 199216
#60 : IVIDEO_B_FRAME : Bits : 106816
#61 : IVIDEO_P_FRAME : Bits : 192616
#62 : IVIDEO_B_FRAME : Bits : 115576
#63 : IVIDEO_P_FRAME : Bits : 206064
#64 : IVIDEO_B_FRAME : Bits : 94328
#65 : IVIDEO_IDR_FRAME : Bits : 525360
#66 : IVIDEO_B_FRAME : Bits : 106600
#67 : IVIDEO_P_FRAME : Bits : 167792
#68 : IVIDEO_B_FRAME : Bits : 84352
#69 : IVIDEO_P_FRAME : Bits : 203176
#70 : IVIDEO_B_FRAME : Bits : 84184
#71 : IVIDEO_P_FRAME : Bits : 228192
#72 : IVIDEO_B_FRAME : Bits : 100552
#73 : IVIDEO_P_FRAME : Bits : 218760
#74 : IVIDEO_B_FRAME : Bits : 101360
#75 : IVIDEO_P_FRAME : Bits : 186064
#76 : IVIDEO_B_FRAME : Bits : 77632
#77 : IVIDEO_P_FRAME : Bits : 188608
#78 : IVIDEO_B_FRAME : Bits : 79448
#79 : IVIDEO_P_FRAME : Bits : 213520
#80 : IVIDEO_B_FRAME : Bits : 127424
#81 : IVIDEO_IDR_FRAME : Bits : 565712
#82 : IVIDEO_B_FRAME : Bits : 148016
#83 : IVIDEO_P_FRAME : Bits : 254176
#84 : IVIDEO_B_FRAME : Bits : 132608
#85 : IVIDEO_P_FRAME : Bits : 227632
#86 : IVIDEO_B_FRAME : Bits : 142864
#87 : IVIDEO_P_FRAME : Bits : 220488
#88 : IVIDEO_B_FRAME : Bits : 137304
#89 : IVIDEO_P_FRAME : Bits : 248480
#90 : IVIDEO_B_FRAME : Bits : 130680
#91 : IVIDEO_P_FRAME : Bits : 235888
#92 : IVIDEO_B_FRAME : Bits : 122440
#93 : IVIDEO_P_FRAME : Bits : 238928
#94 : IVIDEO_B_FRAME : Bits : 103048
#95 : IVIDEO_P_FRAME : Bits : 245064
#96 : IVIDEO_B_FRAME : Bits : 119336
#97 : IVIDEO_IDR_FRAME : Bits : 560960
#98 : IVIDEO_B_FRAME : Bits : 133288
#99 : IVIDEO_P_FRAME : Bits : 204040

Thanks.

Hi Santosh -

I've managed to use the XDM_GETSTATUS call to get the IH264ENC_Status data from the encoder, but the IH264ENC_DynamicParams data comes back all zeroes.  I don't know why.  (I have set the size fields at the beginning of both structs.)  Here is the Status data:

status.videnc2Status.size = 804
status.videnc2Status.extendedError = 0
status.videnc2Status.data.buf = (nil)
status.videnc2Status.data.bufSize = 0
status.videnc2Status.data.accessMask = 0
status.videnc2Status.encodingPreset = 3
status.videnc2Status.rateControlPreset = 5
status.videnc2Status.maxInterFrameInterval = 4
status.videnc2Status.inputChromaFormat = 9
status.videnc2Status.inputContentType = 0
status.videnc2Status.operatingMode = 1
status.videnc2Status.profile = 100
status.videnc2Status.level = 50
status.videnc2Status.inputDataMode = 3
status.videnc2Status.outputDataMode = 3
status.videnc2Status.numInputDataUnits = 1
status.videnc2Status.numOutputDataUnits = 1
status.videnc2Status.configurationID = 1271
status.videnc2Status.bufInfo.minNumInBufs = 0
status.videnc2Status.bufInfo.minNumOutBufs = 0
status.videnc2Status.bufInfo.minNumBufSets = 0
status.videnc2Status.metadataType[] = [ -1 -1 -1 ]
status.videnc2Status.encDynamicParams.size = 236
status.videnc2Status.encDynamicParams.inputHeight = 1080
status.videnc2Status.encDynamicParams.inputWidth = 1920
status.videnc2Status.encDynamicParams.refFrameRate = 60000
status.videnc2Status.encDynamicParams.targetFrameRate = 60000
status.videnc2Status.encDynamicParams.targetBitRate = 3000000
status.videnc2Status.encDynamicParams.intraFrameInterval = 16
status.videnc2Status.encDynamicParams.generateHeader = 0
status.videnc2Status.encDynamicParams.captureWidth = 1920
status.videnc2Status.encDynamicParams.forceFrame = -1
status.videnc2Status.encDynamicParams.interFrameInterval = 2
status.videnc2Status.encDynamicParams.mvAccuracy = 2
status.videnc2Status.encDynamicParams.sampleAspectRatioHeight = 1080
status.videnc2Status.encDynamicParams.sampleAspectRatioWidth = 1920
status.videnc2Status.encDynamicParams.ignoreOutbufSizeFlag = 1
status.videnc2Status.encDynamicParams.putDataFxn = (nil)
status.videnc2Status.encDynamicParams.putDataHandle = (nil)
status.videnc2Status.encDynamicParams.getDataFxn = (nil)
status.videnc2Status.encDynamicParams.getDataHandle = (nil)
status.videnc2Status.encDynamicParams.getBufferFxn = 0x8d8796ed
status.videnc2Status.encDynamicParams.getBufferHandle = (nil)
status.videnc2Status.encDynamicParams.lateAcquireArg = -1
status.rateControlParams.rateControlParamsPreset = 1
status.rateControlParams.scalingMatrixPreset = 1
status.rateControlParams.rcAlgo = 0
status.rateControlParams.qpI = 255
status.rateControlParams.qpMaxI = 50
status.rateControlParams.qpMinI = 5
status.rateControlParams.qpP = 255
status.rateControlParams.qpMaxP = 50
status.rateControlParams.qpMinP = 5
status.rateControlParams.qpOffsetB = 4
status.rateControlParams.qpMaxB = 44
status.rateControlParams.qpMinB = 10
status.rateControlParams.allowFrameSkip = 0
status.rateControlParams.removeExpensiveCoeff = 0
status.rateControlParams.chromaQPIndexOffset = 0
status.rateControlParams.IPQualityFactor = 0
status.rateControlParams.initialBufferLevel = 6000000
status.rateControlParams.HRDBufferSize = 6000000
status.rateControlParams.minPicSizeRatioI = 0
status.rateControlParams.maxPicSizeRatioI = 640
status.rateControlParams.minPicSizeRatioP = 0
status.rateControlParams.maxPicSizeRatioP = 0
status.rateControlParams.minPicSizeRatioB = 0
status.rateControlParams.maxPicSizeRatioB = 0
status.rateControlParams.enablePRC = 1
status.rateControlParams.enablePartialFrameSkip = 0
status.rateControlParams.discardSavedBits = 1
status.rateControlParams.reserved = 0
status.rateControlParams.VBRDuration = 8
status.rateControlParams.VBRsensitivity = 0
status.rateControlParams.skipDistributionWindowLength = 5
status.rateControlParams.numSkipInDistributionWindow = 1
status.rateControlParams.enableHRDComplianceMode = 1
status.rateControlParams.frameSkipThMulQ5 = 0
status.rateControlParams.vbvUseLevelThQ5 = 0
status.rateControlParams.reservedRC[] = [ 0  0 0 ]
status.interCodingParams.interCodingPreset = 0
status.interCodingParams.searchRangeHorP = 144
status.interCodingParams.searchRangeVerP = 32
status.interCodingParams.searchRangeHorB = 144
status.interCodingParams.searchRangeVerB = 16
status.interCodingParams.interCodingBias = 1
status.interCodingParams.skipMVCodingBias = 1
status.interCodingParams.minBlockSizeP = 0
status.interCodingParams.minBlockSizeB = 0
status.interCodingParams.meAlgoMode = 0
status.intraCodingParams.intraCodingPreset = 0
status.intraCodingParams.lumaIntra4x4Enable = 0
status.intraCodingParams.lumaIntra8x8Enable = 255
status.intraCodingParams.lumaIntra16x16Enable = 15
status.intraCodingParams.chromaIntra8x8Enable = 15
status.intraCodingParams.chromaComponentEnable = 1
status.intraCodingParams.intraRefreshMethod = 0
status.intraCodingParams.intraRefreshRate = 0
status.intraCodingParams.gdrOverlapRowsBtwFrames = 0
status.intraCodingParams.constrainedIntraPredEnable = 0
status.intraCodingParams.intraCodingBias = 0
status.nalUnitControlParams.naluControlPreset = 1
status.nalUnitControlParams.naluPresentMaskStartOfSequence = 8608
status.nalUnitControlParams.naluPresentMaskIDRPicture = 8608
status.nalUnitControlParams.naluPresentMaskIntraPicture = 8450
status.nalUnitControlParams.naluPresentMaskNonIntraPicture = 2
status.nalUnitControlParams.naluPresentMaskEndOfSequence = 3072
status.sliceCodingParams.sliceCodingPreset = 1
status.sliceCodingParams.sliceMode = 0
status.sliceCodingParams.sliceUnitSize = 0
status.sliceCodingParams.sliceStartOffset[] = [ 0 0 0 ]
status.sliceCodingParams.streamFormat = 0
status.loopFilterParams.loopfilterPreset = 0
status.loopFilterParams.loopfilterDisableIDC = 0
status.loopFilterParams.filterOffsetA = 0
status.loopFilterParams.filterOffsetB = 0
status.fmoCodingParams.fmoCodingPreset = 0
status.fmoCodingParams.numSliceGroups = 1
status.fmoCodingParams.sliceGroupMapType = 4
status.fmoCodingParams.sliceGroupChangeDirectionFlag = 0
status.fmoCodingParams.sliceGroupChangeRate = 0
status.fmoCodingParams.sliceGroupChangeCycle = 0
status.fmoCodingParams.sliceGroupParams[] = [ 0 0 ]
status.vuiCodingParams.vuiCodingPreset = 1
status.vuiCodingParams.aspectRatioInfoPresentFlag = 0
status.vuiCodingParams.aspectRatioIdc = 255
status.vuiCodingParams.videoSignalTypePresentFlag = 0
status.vuiCodingParams.videoFormat = 5
status.vuiCodingParams.videoFullRangeFlag = 1
status.vuiCodingParams.timingInfoPresentFlag = 1
status.vuiCodingParams.hrdParamsPresentFlag = 1
status.vuiCodingParams.numUnitsInTicks = 1000
status.stereoInfoParams.stereoInfoPreset = 0
status.stereoInfoParams.topFieldIsLeftViewFlag = 1
status.stereoInfoParams.viewSelfContainedFlag = 0
status.framePackingSEIParams.framePackingPreset = 0
status.framePackingSEIParams.framePackingType = 3
status.framePackingSEIParams.frame0PositionX = 0
status.framePackingSEIParams.frame0PositionY = 0
status.framePackingSEIParams.frame1PositionX = 0
status.framePackingSEIParams.frame1PositionY = 0
status.framePackingSEIParams.reservedByte = 0
status.svcCodingParams.svcExtensionFlag = 0
status.svcCodingParams.dependencyID = 0
status.svcCodingParams.qualityID = 0
status.svcCodingParams.enhancementProfileID = 0
status.svcCodingParams.layerIndex = 0
status.svcCodingParams.refLayerDQId = 0
status.interlaceCodingType = 3
status.bottomFieldIntra = 0
status.gopStructure = 0
status.entropyCodingMode = 1
status.transformBlockSize = 2
status.log2MaxFNumMinus4 = 10
status.picOrderCountType = 0
status.enableWatermark = 0
status.IDRFrameInterval = 1
status.maxIntraFrameInterval = 300
status.debugTraceLevel = 1
status.lastNFramesToLog = 31
status.enableAnalyticinfo = 0
status.enableGMVSei = 0
status.constraintSetFlags = 0
status.enableRCDO = 0
status.enableLongTermRefFrame = 0
status.LTRPPeriod = 0
status.searchCenter = 32767,32767
status.enableStaticMBCount = 0
status.extMemoryDebugTraceAddr = 0xb0c49480
status.numTemporalLayer = 1
status.referencePicMarking = 1
status.extMemoryDebugTraceSize = 43008
status.enableROI = 0

Hi Santosh -

I'm still having no luck getting dynamic parameters from the H.264 encoder.  I make the enclink_h264_control(handle, XDM_GETSTATUS, params, status) call and it returns XDM_EOK.  The status structure is filled in with reasonable looking values (shown above), but the params structure is not filled in at all; bogus values I inserted before the call are still there.  I set  params->videnc2DynamicParams.size to sizeof(IH264ENC_DynamicParams) before the call.  I've tried making the call after the encoder is configured but before I send it any frames.  I've also tried making the call after I've sent 100 frames.  Same result both ways.

Looking through the existing code, I don't see any call to XDM_GETSTATUS where the params structure is used after the call, only the status structure.  Does XDM_GETSTATUS actually fill in the dynamic params?

Hi Santosh -

No need to apologize - I hope you had an enjoyable vacation!

I've added code to set the B-frame QP parameters as you suggested.  In the EncLinkH264_algCreate() function, I make these assignments:

    hObj->staticParams.rateControlParams.qpMaxB = 50;
    hObj->staticParams.rateControlParams.qpMinB = 5;
    hObj->dynamicParams.rateControlParams.qpMaxB = 50;
    hObj->dynamicParams.rateControlParams.qpMinB = 5;

then, later in the same function, I make the same assignments again, just before enclink_h264_control(XDM_SETPARAMS) is called.  I immediately read back the values via enclink_h264_control(XDM_GETPARAMS), and they are as I set them.

Then, soon after I send the first frames to the encoder, I again call enclink_h264_control(XDM_GETPARAMS) and the values have changed to

status.rateControlParams.qpMaxB = 44
status.rateControlParams.qpMinB = 10

I don't understand why the values change.  I didn't write most of the application code that I'm using, so I suppose it's possible that there's some application code that's changing the values, but I haven't been able to find any such code.

Is the encoder capable of changing these parameters on its own?

Hi Santosh -

I found and fixed the call that was setting my B-frame QP limits back to the default; it was due to Enclink_h264EncodeFrameBatch() calling EncLinkH264_algSetConfig().  Now, setting qpMaxB to 50 and qpMinB to 5 causes the size of the encoded file to decrease substantially compared to 44 and 10.  However, it is still somewhat larger than the same file encoded at the same bitrate without B-frames, and its PSNR is still 5 to 6 dB worse.  Here are my results for a 739-frame 1920x1080 YUV input stream:

Intra=16, inter=1, VBR: encoded file size = 5,648,671 bytes, PSNR = 27.00 dB

Intra=16, inter=1, CBR: encoded file size = 4,659,759 bytes, PSNR = 26.30 dB

Intra=16, inter=2, VBR, BQP 10-44: encoded file size = 10,005,164 bytes, PSNR = 20.87 dB

Intra=16, inter=2, VBR, BQP 5-50: encoded file size = 5,860,640 bytes, PSNR = 21.06 dB

In all cases, target bitrate = 3Mbps, max bit rate = 6Mbps.

Hi Dave Beal,

Few suggestions from our experts

1. Make sure they are using delta qp=4 btw P and B.
2. B frames need not always help, sometimes it can degrade PSNR (ex: fast moving sequence)
3. I think stream is required if none of the above two help to solve his doubt.
4. Please share the encoded bit stream, encoder configuration, and raw video content.
5. For sharing raw video - You can encode the raw content with high bitrate and IPPPP.. sequence and share the bit stream. This should be nearer to the original video raw.

Hi Santosh -

I've attached an encoded version of my video as an H.264 elementary stream.  The encoder was configured as intra=16, inter=1, CBR, target bitrate=12Mbps, max bitrate=25Mbps.  This was the highest bitrate of this video that would fit in the website's maximum file size.

Also, I don't understand what is meant by "Make sure they are using delta qp=4 btw P and B."  I am setting status.rateControlParams.qpOffsetB = 4.  Is this what you mean?

I will be out of the office beginning tomorrow, returning next Wednesday (8/28).  I will try to check for updates while I am out.

Hi Dave Beal,

Your understanding for Qp delta/ QpOffsetB is correct. It is 4 as I have had a look to your encoder configuration.

1. Reason for IBPBP... file size more than IPPPP.. file size : You had set [QpMinP,QpMaxP] =  [5,50] & [QpMinB,QpMaxB] =  [10,44] and bitrate as 3MBPS for full HD resolution. So because of this low bitrate for HD resolution, our encoder always tries to code with possible high Qp. And since you had restricted 'B' frame Qp not to go beyond 44, the size of 'B' frames were more than that of 'P' frames. We could reproduce such a observation at our setup(using your encoder configuration] and above given reason is right for this behaviour.
2. Reason for bad PSNR for IBPBP.. sequence compared to IPPPP.. sequence : As said earlier in this thread that 'B' frames always shall not improve the PSNR, sometime (fast moving scenes) they may degrade too.In case of fast moving scenes 'B' frames has to code lot of motion information and hence need more bits. If bits are not available(less bitrate cases ) then our encoder starts coding the information with less quality to meet the network bit rate and hence less quality video.

Hi Dave Beal,

Please follow the thread http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/p/252361/997917.aspx#997917

Thanks,

Hi Santosh -

Your suggestions have solved my B-frame mystery.  As you suggested, increasing the B-frame QP range from [10-44] to [5-50] resolved the encoded file size problem, and I've now verified that fixing the code in src_bios6/links_m3video/iva_enc/encLink_h264.c to return input buffers for release only when indicated by outArgs->videnc2OutArgs.freeBufID[] solved the PSNR problem.

When I enable B-frames by increasing interframeInterval from 1 to 2, I now get an encoded file size that is slightly smaller and a PSNR value that is very slightly better than without B-frames.  Thanks for your help!

Dave Beal, 

Good to hear it!! 

Thanks and Regards,

Santoshkumar S K