Add better documentation for filter extension
Change-Id: I17cae8bccf7c761d9f80469edf4f2e98255654f9
diff --git a/tools/lanczos/lanczos_README.txt b/tools/lanczos/lanczos_README.txt
index aee2761..f15b87e 100644
--- a/tools/lanczos/lanczos_README.txt
+++ b/tools/lanczos/lanczos_README.txt
@@ -42,6 +42,8 @@
<y4m_output>
[<outwidth>x<outheight>]
Notes:
+ <y4m_input> is the input video in Y4M format
+ <y4m_output> is the output video in Y4M format
<num_frames> is number of frames to be processed
<horz_p>/<horz_q> gives the horz resampling ratio.
<vert_p>/<vert_q> gives the vert resampling ratio.
@@ -53,11 +55,15 @@
using the inverse of the number provided,
or 'c' meaning centered
<horz_ext>, <vert_ext> are optional extension types:
- 'r' or 'rep' (Repeat)
+ 'r' or 'rep' (Repeat) [default]
+ [ ... x0 x0 x0 | x0 x1 x2 ... ]
's' or 'sym' (Symmetric)
+ [ ... x2 x1 x0 | x0 x1 x2 ... ]
'f' or 'ref' (Reflect/Mirror-whole)
+ [ ... x3 x2 x1 | x0 x1 x2 ... ]
'g' or 'gra' (Gradient preserving)
- [default: 'r']
+ [ ... y3 y2 y1 | x0 x1 x2 ... ] with:
+ yi = 2 * x0 - xi, i = 1, 2, 3, ...
<outwidth>x<outheight> is output video dimensions
only needed in case of upsampling
Resampling config string of 1:1:1:0 horizontally or vertically
@@ -125,30 +131,14 @@
<yuv_output>
[<outwidth>x<outheight>]
Notes:
+ <yuv_input> is the input video in raw YUV format
+ <yuv_output> is the output video in raw YUV format
<width>x<height> is input video dimensions.
<pix_format> is one of { yuv420p, yuv420p10, yuv420p12,
yuv422p, yuv422p10, yuv422p12,
yuv444p, yuv444p10, yuv444p12 }
- <num_frames> is number of frames to be processed
- <horz_p>/<horz_q> gives the horz resampling ratio.
- <vert_p>/<vert_q> gives the vert resampling ratio.
- <Lanczos_horz_a>, <Lanczos_vert_a> are Lanczos parameters.
- <horz_x0>, <vert_x0> are optional initial offsets
- [default centered].
- If used, they can be a number in (-1, 1),
- or a number in (-1, 1) prefixed by 'i' meaning
- using the inverse of the number provided,
- or 'c' meaning centered
- <horz_ext>, <vert_ext> are optional extension types:
- 'r' or 'rep' (Repeat)
- 's' or 'sym' (Symmetric)
- 'f' or 'ref' (Reflect/Mirror-whole)
- 'g' or 'gra' (Gradient preserving)
- [default: 'r']
- <outwidth>x<outheight> is output video dimensions
- only needed in case of upsampling
- Resampling config string of 1:1:1:0 horizontally or vertically
- is regarded as a no-op in that direction.
+ All other parameters are the same as the ones used for
+ lanczos_resample_y4m described above.
SCRIPTS
