The Independent JPEG Group's JPEG software v8d
diff --git a/usage.txt b/usage.txt
index eae5842..de9def7 100644
--- a/usage.txt
+++ b/usage.txt
@@ -77,6 +77,12 @@
saying -grayscale, you'll get a smaller JPEG file that
takes less time to process.
+ -rgb Create RGB JPEG file.
+ Using this switch suppresses the conversion from RGB
+ colorspace input to the default YCbCr JPEG colorspace.
+ Use this switch in combination with the -block N
+ switch (see below) for lossless JPEG coding.
+
-optimize Perform optimization of entropy encoding parameters.
Without this, default encoding parameters are used.
-optimize usually makes the JPEG file a little smaller,
@@ -151,6 +157,11 @@
Switches for advanced users:
+ -arithmetic Use arithmetic coding. CAUTION: arithmetic coded JPEG
+ is not yet widely implemented, so many decoders will
+ be unable to view an arithmetic coded JPEG file at
+ all.
+
-block N Set DCT block size. All N from 1 to 16 are possible.
Default is 8 (baseline format).
Larger values produce higher compression,
@@ -210,11 +221,6 @@
Switches for wizards:
- -arithmetic Use arithmetic coding. CAUTION: arithmetic coded JPEG
- is not yet widely implemented, so many decoders will
- be unable to view an arithmetic coded JPEG file at
- all.
-
-baseline Force baseline-compatible quantization tables to be
generated. This clamps quantization values to 8 bits
even at low quality settings. (This switch is poorly
@@ -459,9 +465,9 @@
jpegtran accepts a subset of the switches recognized by cjpeg:
-optimize Perform optimization of entropy encoding parameters.
-progressive Create progressive JPEG file.
+ -arithmetic Use arithmetic coding.
-restart N Emit a JPEG restart marker every N MCU rows, or every
N MCU blocks if "B" is attached to the number.
- -arithmetic Use arithmetic coding.
-scans file Use the scan script given in the specified text file.
See the previous discussion of cjpeg for more details about these switches.
If you specify none of these switches, you get a plain baseline-JPEG output