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authorMathis Rosenhauer <rosenhauer@dkrz.de>2016-01-15 16:48:40 (GMT)
committerMathis Rosenhauer <rosenhauer@dkrz.de>2016-01-15 16:48:40 (GMT)
commit52427266b94da18a78ffa0cab1fac810e009eb98 (patch)
tree40c65d1b42f510d67b5516a5d3b0ee40793cd3ff
parent7bd95ff2d586a1f5fa251735537a69c0ce110538 (diff)
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Docs update.
-rw-r--r--README21
1 files changed, 14 insertions, 7 deletions
diff --git a/README b/README
index dc101fd..c13755b 100644
--- a/README
+++ b/README
@@ -86,9 +86,9 @@ output goes into *dest.
...
block_size can vary from 8 to 64 samples. Smaller blocks allow the
-compression to adapt to rapid changes in entropy. Larger blocks create
-less overhead but can be less efficient if entropy changes across the
-block.
+compression to adapt more rapidly to changing source
+statistics. Larger blocks create less overhead but can be less
+efficient if source statistics change across the block.
rsi sets the reference sample interval. A large RSI will improve
performance and efficiency. It will also increase memory requirements
@@ -111,7 +111,8 @@ i.e. big endian. You have to specify AEC_DATA_MSB even if your host
architecture is big endian. Default is little endian on all
architectures.
-AEC_DATA_3BYTE: the 24 bit input data is stored in three bytes.
+AEC_DATA_3BYTE: the 17 to 24 bit input data is stored in three
+bytes. This flag has no effect for other sample sizes.
AEC_RESTRICTED: use a restricted set of code options. This option is
only valid for bits_per_sample <= 4.
@@ -123,14 +124,15 @@ flag.
Data size:
-Except for the AEC_DATA_3BYTE case for 24 bit data, the following
-rules apply for deducing storage size from sample size
+Except for the AEC_DATA_3BYTE case for 17 to 24 bit data, the
+following rules apply for deducing storage size from sample size
(bits_per_sample):
sample size storage size
1 - 8 bits 1 byte
9 - 16 bits 2 bytes
-17 - 32 bits 4 bytes (also for 24bit if AEC_DATA_3BYTE is not set)
+17 - 32 bits 4 bytes (also for 17 to 24 bits if AEC_DATA_3BYTE is
+ not set)
If a sample requires less bits than the storage size provides, then
you have to make sure that unused bits are not set. Libaec does not
@@ -192,6 +194,11 @@ and output is reversed.
aec_decode_end(&strm);
...
+The size of the output buffer (next_out) should be a multiple of the
+storage size in bytes. If the buffer is not a multiple of the storage
+size and the buffer would be filled to the last sample, the error code
+AEC_MEM_ERROR is returned.
+
It is essential for decoding that parameters like bits_per_sample,
block_size, rsi, and flags are exactly the same as they were for
encoding. Libaec does not store these parameters in the coded stream