This chapter provides an overview of the information contained in the functional descriptions.
Video Coding library functional descriptions include the following types of information.
Video Coding library function definitions use the following enumerators.
| FwvcFrameFieldFlag | Enumerates image type of the picture. | |
| fwintra16x16PredMode_H264 | Enumerates prediction modes for the Intra_16x16 prediction process of luma compoments. | |
| fwintra4x4PredMode_H264 | Enumerates prediction modes for the Intra_4x4 prediction process of luma compoments. | |
| fwintraChromaPredMode_H264 | Enumerates prediction modes for the Intra prediction process of chroma compoments. |
Video Coding library function definitions use the following parameters.
| AC | AC compoment | |
| ChromaQP | Chroma quantizer, must be within the range [0;39]. | |
| DstStep | Size of a row in bytes, the aligned destination frame width. | |
| EdgePelCount | Specifies the minimum number of pairs of elements that differ by more than EdgePelDifference. | |
| EdgePelDifference | Specifies the edge difference threshold between neighboring elements. | |
| PredStep | Reference plane step size (in bytes). | |
| QP | Quantizer scale factor read from the bitstream. | |
| StartPtr | Pointer to frame source data. | |
| Switch | Flag that indicates picture switch (non-zero when a switch occurs, equal to zero otherwise). | |
| availability | Flag that indicates availability of the samples used for prediction. | |
| cbp4x2 | Coded block pattern. If cbp4x2 & (1<<(1+i))is not equal to 0 (0 < i < 8), i-th 4x4 AC. Luma block is not zero-filled and it exists in ppSrcCoeff. | |
| cbp4x4 | Coded block pattern. If cbp4x4 & (1<<(1+i))is not equal to 0 (0 < i < 16), i-th 4x4 AC. Luma block is not zero-filled and it exists in ppSrcCoeff. | |
| count | Number of the last non-zero coefficient in zig-zag order. When a block contains no non-zero coefficients, the value is -1. | |
| countU | Number of the last non-zero U coefficient in zig-zag order. When a block contains no non-zero coefficients, the value is -1. | |
| countV | Number of the last non-zero V coefficient in zig-zag order. When a block contains no non-zero coefficients, the value is -1. | |
| dstDiffStep | Destination block step size (width of the block in bytes). | |
| dstPredictorStep | Destination predictor block step size (width of the block in bytes). | |
| dstStep | Step of the destination array. | |
| dx | Fractional part of the x-coordinate in a source image. | |
| dy | Fractional part of the y-coordinate in a source image. | |
| edgeType | Specifies a vertical or horizontal edge. | |
| edgeTypeBottom | Flag that indicates the availability of the upper half of a macroblock used for prediction. The upper and lower halves of a macroblock may have different prediction vectors. There is one flag for each half. | |
| edgeTypeTop | Flag that indicates the availability of the lower half of a macroblock used for prediction. The upper and lower halves of a macroblock may have different prediction vectors. There is one flag for each half. | |
| height | Specifies the height of a block. | |
| intraChromaMode | Specifies the operating mode of the intrachroma prediction process. | |
| isSigned | Flag that indicates whether an output value must be decoded as signed. | |
| mcType | Specifies the type of prediction used for motion compensation. | |
| mcTypeB | Specifies the type of prediction used for backward frame motion compensation. | |
| mcTypeF | Specifies the type of prediction used for forward frame motion compensation. | |
| nAlpha | A calculated deblock filter value. | |
| nBeta | A calculated deblock filter value. | |
| offset | Specifies an offset. | |
| outPixels | The number of pixels by which the data specified by pSrc reaches over the frame top boundary. | |
| pACTable | Pointer to a table containing run-level codes for all DCT coefficients other than the first one. | |
| pAlpha | Pointer to an array of size 2 of alpha thresholds (values for external and internal vertical edge). | |
| pBS | Pointer to an array of size 16 of BS parameters (values for the left edge of each 4x4 block). | |
| pBeta | Pointer to an array of size 2 of beta thresholds (values for external and internal vertical edge). | |
| pBitOffset | Pointer to a bit position within the byte that ppBitStream points to. Valid within the range 0 to 7. The pointer is updated after motion vector decoding. | |
| pDC | Pointer to an output coefficient. | |
| pDCPred | Pointer to a value to be added to the DC coefficient. The value is read from the standard table. | |
| pDCPredict | Pointer to an array (size 4) of the of inter-prediction DC samples for the current macroblock after inverse transform. Inverse transform of the inter prediction samples can be calculated using TransformPrediction_H264 function for each 4x4 block. | |
| pDCSizeTable | Pointer to a table containing codes for the DC coefficient (the first of the DCT coefficients). | |
| pDCTable | Pointer to a table containing codes for the DC coefficient (the first of the DCT coefficients). | |
| pDecodeTable | Pointer to a decoding table. | |
| pDiff | Pointer to an array of size 16 that contains the sums of 4X4 difference block coefficients. | |
| pDst | Pointer to a location in a destination buffer, a location in a destination array or to a destination result. | |
| pDstBlock | Pointer to a block of decoded elements. | |
| pDstDiff | Pointer to a 16X16 block in the destination plane which contains differences between current and reference blocks. | |
| pDstPredictor | Pointer to a destination predictor block. | |
| pDstSAD | Pointer to a destination array of size 4 that stores SAD values. | |
| pDstSize | Pointer to the position of the last non-zero block coefficient in scanning sequence. | |
| pDstUV | Pointer to a UV destination array. | |
| pFirst | Pointer to the first destination value. | |
| pMBIntraTypes | Pointer to an array of Intra_4x4 luma prediction modes for eight subblocks. pMBIntraTypes[i] is defined in the same way as in PredictIntra_4x4_H264 function (0 < i < 8 ). | |
| pMean | Pointer to a computed mean of pixel values. | |
| pNumCoeff | Pointer to the output number of non-zero coefficients. | |
| pOffset | Pointer to the offset between the bit that ppBitStream points to and the start of the code. | |
| pPred | Pointer to a 16x16 predictor block in the reference plane. | |
| pPredictBlock | Pointer to array (size 16) of inter-prediction samples for the current macroblock after inverse transform. Samples are calculated using the TransformPrediction_H264 function. | |
| pQPMatrix | Pointer to a standard or user-defined weighting matrix. | |
| pRef | Pointer to a prefetch buffer which contains previously decoded bits. | |
| pRefB | Pointer to a backward-reference block of specified size. | |
| pRefF | Pointer to a forward-reference block of specified size. | |
| pRes | Pointer to a result value. | |
| pSAD | Pointer to an SAD result. | |
| pScanMatrix | Pointer to a matrix containing indices of elements in a scanning sequence. | |
| pSecond | Pointer to a second destination value. | |
| pSqrDiff | Pointer to a sum of square differences between the current and reference blocks. | |
| pSrc | Pointer to a block of DCT coefficients. | |
| pSrc1 | Pointer to a location in source buffer one. | |
| pSrc2 | Pointer to a location in source buffer two. | |
| pSrc2Dst | Pointer to the second source and result. | |
| pSrcCur | Pointer to a block in the current plane. | |
| pSrcDst | Pointer to the start of the block. | |
| pSrcDstUPlane | Pointer to a macroblock that is reconstructed in the current U plane. The macroblock must contain inter-prediction samples. | |
| pSrcDstVPlane | Pointer to a macroblock that is reconstructed in the current V plane. The macroblock must contain inter-prediction samples. | |
| pSrcDstYPlane | Pointer to the current macroblock that is reconstructed in current Y-plane. This macroblock must contain inter prediction samples. | |
| pSrcRef | Pointer to a block in the reference plane. | |
| pSrcRefB | Pointer to a backward block in the reference plane. | |
| pSrcRefF | Pointer to a forward block in the reference plane. | |
| pSrcSum | Pointer to a sum of pixel values for the current block. | |
| pSrcTable | Pointer to a source table. | |
| pSrcU | Pointer to a block of DCT coefficients for U component. | |
| pSrcV | Pointer to a block of DCT coefficients for V component. | |
| pSrcYData | Pointer to a block of inverse DCT output data. | |
| pSums | Pointer to an array of size 256 that contains a sequence of 4X4 residual blocks. | |
| pTblCoeffToken | Pointer to a table of coefficient tokens. | |
| pThresholds | Pointer to an array of size 16 of threshold (Tc0) values for the left edge of each 4x4 block. | |
| pVar | Pointer to a variance value. | |
| pitch | Specifies memory pitch. | |
| ppBitStream | Double pointer to the current position in the bit stream. | |
| ppDecodeTable | Double pointer to a decoding table. | |
| ppDstCoeffs | Double pointer to a 4x4 block of coefficients calculated by the function. The function shifts pointer *ppDstCoeffs on 16. | |
| ppDstSpec | Double pointer to a destination decoding table. | |
| ppSrcCoeff | Double pointer to the order of 4x4 blocks of residual coefficients for a macroblock, the results of Huffman decoding (2x2 DC U-block, 2x2 DC V-block, 4x4 AC U-blocks, 4x4 AC V-blocks if the block is not zero-filled). The pointer is updated by the function and points to the blocks for the next macroblock. | |
| ppTblCoeffToken | Double pointer to a CoeffToken table. | |
| ppTblRunBefore | Double pointer to a RunBefore table. | |
| ppTblTotalZeros | Double pointer to a TotalZeros table. | |
| ppTblTotalZerosCR | Double pointer to a chroma DC TotalZeros table. | |
| predMode | Specifies the prediction mode of the Intra_4x4 prediction process for luma samples. | |
| predStep | Reference plane step size (in bytes). | |
| qp | Quantization parameter (QPY in [JVTG050]). It must be within the range [0;51]. | |
| qs | Quantization parameter qs. | |
| refStep | Reference block step size (width of the block in bytes). | |
| refStepB | Backward reference frame reference block step size (width of the block in bytes). | |
| refStepF | Forward reference frame reference block step size (width of the block in bytes). | |
| roiSize | Specifies the height and width of an ROI. | |
| roundControl | Specifies the type of rounding used for half-pixel approximation. | |
| shift | Specifies shift size. | |
| shiftDCVal | Integer value. The DC coefficient must be multiplied by 2shiftDCVal. | |
| srcCurStep | Source current block step size (width of the block in bytes) | |
| srcDstStep | Source and destination buffer step size in bytes (width of both buffers in bytes). | |
| srcDstUVStep | Plane step size. | |
| srcDstYStep | Y-plane step size. | |
| srcRefStep | Source reference block step size (width of the block in bytes) | |
| srcRefStepB | Source backward reference block step size (width of the block in bytes) | |
| srcRefStepF | Source forward reference block step size (width of the block in bytes) | |
| srcStep | Source buffer step size (width of the buffer in bytes). | |
| srcStepB | Source-aligned backward reference frame step size (width in bytes). | |
| srcStepF | Source-aligned forward reference frame step size (width in bytes). | |
| srcYDataStep | Source-aligned DCT output data block step size (width of the block in bytes). | |
| step | Plane step | |
| uFrameFieldFlag | Flag that indicates an expansion method for various image types: frame, top field, bottom field. | |
| uFrameHeight | Frame height in pixels. | |
| uFrameWidth | Frame width in pixels. | |
| uMaxNumCoeff | Maximum number of coefficients in a block (16 for Intra 16x16, 15 for others). | |
| uPels | Number of pixels filled to the right/left and up/down in process of expansion. | |
| uPitch | Frame width in bytes. | |
| uVLCSelect | Predictor on number of CoeffToken table. | |
| weight1 | Weighting factor. | |
| weight2 | Weighting factor. | |
| width | Block width. |