Rename DOCS/tech/ to DOCS/OUTATED-tech/

While DOCS/tech/ contains lots of documentation about mplayer's
internals, most of it seems outdated, and hasn't been touched in many
years. On the other hand, there still might be useful things in there,
but it's hard to tell which parts.

Instead of deleting all it, rename the directory to "warn" potential
developers that the documentation is completely outdated.

1 files changed, 68 insertions, 0 deletions

diff --git a/DOCS/OUTDATED-tech/swscaler_methods.txt b/DOCS/OUTDATED-tech/swscaler_methods.txt
new file mode 100644
index 0000000000..24d2b11835
--- /dev/null
+++ b/DOCS/OUTDATED-tech/swscaler_methods.txt
@@ -0,0 +1,68 @@
+
+artifact types:
+---------------------------------------------------------------------
+ringing
+        wave or noise like patterns around sharp edges
+        bad: sinc, lanczos (with high filter length)
+        acceptable: lanczos (with low filter length), cubic, spline
+        ok: area, (fast)blinear, gauss, point
+
+blur
+        loss of detail / high frequency
+        bad: gauss with high variance
+        acceptable: (fast)bilinear, area
+        ok: others
+
+aliasing (only downscale)
+        straight lines look like staircases
+        areas of high detail look worse
+        regular patterns turn into a funny looking mess (moire patterns)
+        bad: fast bilinear, point, gauss with low variance
+        acceptable: area
+        ok: others
+
+blocky (upscale only)
+        looks like the image is made of rectangular blocks like a mosaic
+        bad: point
+        ok: others
+
+recommendations: (based upon my personal opinion many ppl might disagree ...)
+---------------------------------------------------------------------
+
+the recommended scalers for upscaling:
+fast_bilinear, point if speed is important
+cubic, spline, lanczos if quality is important
+
+the recommended scalers for downscaling:
+fast_bilinear, point if speed is important
+gauss, bilinear if quality is important
+cubic, spline, lanczos if a sharper picture is important
+
+note: when encoding at a limited amount of bits (not constant quantizer)
+then a slightly blurred input might look better after decoding than a slightly
+sharpened one, especially for lower bitrates
+
+sws numbers / names / artifact types
+-------------------------------------------------------------------------
+r ringing
+b blurry
+a aliasing (downscale only)
+m mosaic (blocky) (upscale only)
+
+-sws 0  fast bilinear                   bA
+-sws 1  bilinear                        b
+-sws 2  bicubic high sharpness          r
+                low sharpness           b
+-sws 3  experimental                    ????
+-sws 4  nearest neighbour               AM
+-sws 5  area                            ba
+-sws 6  luma bicubic / chroma bilinear  r
+-sws 7  gauss   low sharpness           B
+                high sharpness          AM
+-sws 8  sinc                            R
+-sws 9  lanczos long filter             R
+                short filter            b
+-sws 10 bicubic spline                  r
+
+Notes:
+        area upscale is identical to bilinear