[FFmpeg-cvslog] lavu/tx: improve documentation
Lynne
git at videolan.org
Mon Mar 23 23:36:06 EET 2020
ffmpeg | branch: master | Lynne <dev at lynne.ee> | Sat Mar 14 16:10:06 2020 +0000| [9f494d1397d123efd23cf772eb381e194785f4ea] | committer: Lynne
lavu/tx: improve documentation
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9f494d1397d123efd23cf772eb381e194785f4ea
---
libavutil/tx.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/libavutil/tx.h b/libavutil/tx.h
index 53018c84e6..cacfd604d1 100644
--- a/libavutil/tx.h
+++ b/libavutil/tx.h
@@ -40,11 +40,17 @@ enum AVTXType {
/**
* Standard complex to complex FFT with sample data type AVComplexFloat.
* Output is not 1/len normalized. Scaling currently unsupported.
+ * The stride parameter is ignored.
*/
AV_TX_FLOAT_FFT = 0,
/**
* 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)
+ * 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).
*/
AV_TX_FLOAT_MDCT = 1,
/**
@@ -53,6 +59,7 @@ enum AVTXType {
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_DOUBLE_MDCT = 3,
/**
@@ -62,6 +69,7 @@ enum AVTXType {
/**
* 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,
};
@@ -75,8 +83,11 @@ enum AVTXType {
* @param s the transform context
* @param out the output array
* @param in the input array
- * @param stride the input or output stride (depending on transform direction)
- * in bytes, currently implemented for all MDCT transforms
+ * @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.
+ * 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);
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