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lavu/tx: improve documentation for existing transforms

This commit is contained in:
Lynne 2022-01-25 04:45:34 +01:00
parent 3c804fdd4a
commit c14976be04
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1 changed files with 15 additions and 30 deletions
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45
libavutil/tx.h
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@ -38,50 +38,35 @@ typedef struct AVComplexInt32 {
enum AVTXType {
/**
* Standard complex to complex FFT with sample data type AVComplexFloat.
* Standard complex to complex FFT with sample data type of AVComplexFloat,
* AVComplexDouble or AVComplexInt32, for each respective variant.
*
* Output is not 1/len normalized. Scaling currently unsupported.
* The stride parameter is ignored.
* The stride parameter must be set to the size of a single sample in bytes.
*/
AV_TX_FLOAT_FFT = 0,
AV_TX_FLOAT_FFT = 0,
AV_TX_DOUBLE_FFT = 2,
AV_TX_INT32_FFT = 4,
/**
* Standard MDCT with sample data type of float and a scale type of
* float. Length is the frame size, not the window size (which is 2x frame)
* Standard MDCT with a sample data type of float, double or int32_t,
* respecively. For the float and int32 variants, the scale type is
* 'float', while for the double variant, it's 'double'.
*
* Length is the frame size, not the window size (which is 2x frame).
* For forward transforms, the stride specifies the spacing between each
* sample in the output array in bytes. The input must be a flat array.
*
* For inverse transforms, the stride specifies the spacing between each
* sample in the input array in bytes. The output will be a flat array.
* Stride must be a non-zero multiple of sizeof(float).
* sample in the input array in bytes. The output must be a flat array.
*
* NOTE: the inverse transform is half-length, meaning the output will not
* contain redundant data. This is what most codecs work with. To do a full
* inverse transform, set the AV_TX_FULL_IMDCT flag on init.
*/
AV_TX_FLOAT_MDCT = 1,
/**
* Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
*/
AV_TX_DOUBLE_FFT = 2,
/**
* Same as AV_TX_FLOAT_MDCT with data and scale type of double.
* Stride must be a non-zero multiple of sizeof(double).
*/
AV_TX_FLOAT_MDCT = 1,
AV_TX_DOUBLE_MDCT = 3,
/**
* Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
*/
AV_TX_INT32_FFT = 4,
/**
* Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float.
* Only scale values less than or equal to 1.0 are supported.
* Stride must be a non-zero multiple of sizeof(int32_t).
*/
AV_TX_INT32_MDCT = 5,
AV_TX_INT32_MDCT = 5,
};
/**