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FFmpeg 5.1.6
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#include <stdint.h>#include <stddef.h>Go to the source code of this file.
Data Structures | |
| struct | AVComplexFloat |
| struct | AVComplexDouble |
| struct | AVComplexInt32 |
Typedefs | |
| typedef struct AVTXContext | AVTXContext |
| typedef void(* | av_tx_fn) (AVTXContext *s, void *out, void *in, ptrdiff_t stride) |
| Function pointer to a function to perform the transform. More... | |
Enumerations | |
| enum | AVTXType { AV_TX_FLOAT_FFT = 0 , AV_TX_DOUBLE_FFT = 2 , AV_TX_INT32_FFT = 4 , AV_TX_FLOAT_MDCT = 1 , AV_TX_DOUBLE_MDCT = 3 , AV_TX_INT32_MDCT = 5 , AV_TX_FLOAT_RDFT = 6 , AV_TX_DOUBLE_RDFT = 7 , AV_TX_INT32_RDFT = 8 , AV_TX_NB } |
| enum | AVTXFlags { AV_TX_INPLACE = 1ULL << 0 , AV_TX_UNALIGNED = 1ULL << 1 , AV_TX_FULL_IMDCT = 1ULL << 2 } |
| Flags for av_tx_init() More... | |
Functions | |
| int | av_tx_init (AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type, int inv, int len, const void *scale, uint64_t flags) |
| Initialize a transform context with the given configuration (i)MDCTs with an odd length are currently not supported. More... | |
| void | av_tx_uninit (AVTXContext **ctx) |
| Frees a context and sets *ctx to NULL, does nothing when *ctx == NULL. More... | |
| typedef struct AVTXContext AVTXContext |
| typedef void(* av_tx_fn) (AVTXContext *s, void *out, void *in, ptrdiff_t stride) |
Function pointer to a function to perform the transform.
| s | the transform context |
| out | the output array |
| in | the input array |
| stride | the input or output stride in bytes |
The out and in arrays must be aligned to the maximum required by the CPU architecture unless the AV_TX_UNALIGNED flag was set in av_tx_init(). The stride must follow the constraints the transform type has specified.
| enum AVTXType |
| Enumerator | |
|---|---|
| AV_TX_FLOAT_FFT | 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 must be set to the size of a single sample in bytes. |
| AV_TX_DOUBLE_FFT | |
| AV_TX_INT32_FFT | |
| AV_TX_FLOAT_MDCT | 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'. If scale is NULL, 1.0 will be used as a default. 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 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_DOUBLE_MDCT | |
| AV_TX_INT32_MDCT | |
| AV_TX_FLOAT_RDFT | Real to complex and complex to real DFTs. For the float and int32 variants, the scale type is 'float', while for the double variant, it's a 'double'. If scale is NULL, 1.0 will be used as a default. The stride parameter must be set to the size of a single sample in bytes. The forward transform performs a real-to-complex DFT of N samples to N/2+1 complex values. The inverse transform performs a complex-to-real DFT of N/2+1 complex values to N real samples. The output is not normalized, but can be made so by setting the scale value to 1.0/len. NOTE: the inverse transform always overwrites the input. |
| AV_TX_DOUBLE_RDFT | |
| AV_TX_INT32_RDFT | |
| AV_TX_NB | |
| enum AVTXFlags |
Flags for av_tx_init()
| Enumerator | |
|---|---|
| AV_TX_INPLACE | Performs an in-place transformation on the input. The output argument of av_tn_fn() MUST match the input. May be unsupported or slower for some transform types. |
| AV_TX_UNALIGNED | Relaxes alignment requirement for the in and out arrays of av_tx_fn(). May be slower with certain transform types. |
| AV_TX_FULL_IMDCT | Performs a full inverse MDCT rather than leaving out samples that can be derived through symmetry. Requires an output array of 'len' floats, rather than the usual 'len/2' floats. Ignored for all transforms but inverse MDCTs. |
| int av_tx_init | ( | AVTXContext ** | ctx, |
| av_tx_fn * | tx, | ||
| enum AVTXType | type, | ||
| int | inv, | ||
| int | len, | ||
| const void * | scale, | ||
| uint64_t | flags | ||
| ) |
Initialize a transform context with the given configuration (i)MDCTs with an odd length are currently not supported.
| ctx | the context to allocate, will be NULL on error |
| tx | pointer to the transform function pointer to set |
| type | type the type of transform |
| inv | whether to do an inverse or a forward transform |
| len | the size of the transform in samples |
| scale | pointer to the value to scale the output if supported by type |
| flags | a bitmask of AVTXFlags or 0 |
| void av_tx_uninit | ( | AVTXContext ** | ctx | ) |
Frees a context and sets *ctx to NULL, does nothing when *ctx == NULL.
1.9.4