* float. 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).
+ *
* NOTE: the inverse transform is half-length, meaning the output will not
* contain redundant data. This is what most codecs work with.
*/
* @param stride the input or output stride in bytes
*
* The out and in arrays must be aligned to the maximum required by the CPU
- * architecture.
+ * architecture unless the AV_TX_UNALIGNED flag was set in av_tx_init().
* The stride must follow the constraints the transform type has specified.
*/
typedef void (*av_tx_fn)(AVTXContext *s, void *out, void *in, ptrdiff_t stride);
+/**
+ * Flags for av_tx_init()
+ */
+enum AVTXFlags {
+ /**
+ * 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_INPLACE = 1ULL << 0,
+
+ /**
+ * Relaxes alignment requirement for the in and out arrays of av_tx_fn().
+ * May be slower with certain transform types.
+ */
+ AV_TX_UNALIGNED = 1ULL << 1,
+};
+
/**
* Initialize a transform context with the given configuration
* (i)MDCTs with an odd length are currently not supported.
* @param inv whether to do an inverse or a forward transform
* @param len the size of the transform in samples
* @param scale pointer to the value to scale the output if supported by type
- * @param flags currently unused
+ * @param flags a bitmask of AVTXFlags or 0
*
* @return 0 on success, negative error code on failure
*/