summaryrefslogtreecommitdiffstats
path: root/media/libaom/src/usage_dx.dox
diff options
context:
space:
mode:
authorMatt A. Tobin <email@mattatobin.com>2020-04-07 23:30:51 -0400
committerwolfbeast <mcwerewolf@wolfbeast.com>2020-04-14 13:26:42 +0200
commit277f2116b6660e9bbe7f5d67524be57eceb49b8b (patch)
tree4595f7cc71418f71b9a97dfaeb03a30aa60f336a /media/libaom/src/usage_dx.dox
parentd270404436f6e84ffa3b92af537ac721bf10d66e (diff)
downloadUXP-277f2116b6660e9bbe7f5d67524be57eceb49b8b.tar
UXP-277f2116b6660e9bbe7f5d67524be57eceb49b8b.tar.gz
UXP-277f2116b6660e9bbe7f5d67524be57eceb49b8b.tar.lz
UXP-277f2116b6660e9bbe7f5d67524be57eceb49b8b.tar.xz
UXP-277f2116b6660e9bbe7f5d67524be57eceb49b8b.zip
Move aom source to a sub-directory under media/libaom
There is no damned reason to treat this differently than any other media lib given its license and there never was.
Diffstat (limited to 'media/libaom/src/usage_dx.dox')
-rw-r--r--media/libaom/src/usage_dx.dox57
1 files changed, 57 insertions, 0 deletions
diff --git a/media/libaom/src/usage_dx.dox b/media/libaom/src/usage_dx.dox
new file mode 100644
index 000000000..eef78376f
--- /dev/null
+++ b/media/libaom/src/usage_dx.dox
@@ -0,0 +1,57 @@
+/*! \page usage_decode Decoding
+
+ The aom_codec_decode() function is at the core of the decode loop. It
+ processes packets of compressed data passed by the application, producing
+ decoded images. The decoder expects packets to comprise exactly one image
+ frame of data. Packets \ref MUST be passed in decode order. If the
+ application wishes to associate some data with the frame, the
+ <code>user_priv</code> member may be set.
+
+ \ref samples
+
+
+ \section usage_cb Callback Based Decoding
+ There are two methods for the application to access decoded frame data. Some
+ codecs support asynchronous (callback-based) decoding \ref usage_features
+ that allow the application to register a callback to be invoked by the
+ decoder when decoded data becomes available. Decoders are not required to
+ support this feature, however. Like all \ref usage_features, support can be
+ determined by calling aom_codec_get_caps(). Callbacks are available in both
+ frame-based and slice-based variants. Frame based callbacks conform to the
+ signature of #aom_codec_put_frame_cb_fn_t and are invoked once the entire
+ frame has been decoded. Slice based callbacks conform to the signature of
+ #aom_codec_put_slice_cb_fn_t and are invoked after a subsection of the frame
+ is decoded. For example, a slice callback could be issued for each
+ macroblock row. However, the number and size of slices to return is
+ implementation specific. Also, the image data passed in a slice callback is
+ not necessarily in the same memory segment as the data will be when it is
+ assembled into a full frame. For this reason, the application \ref MUST
+ examine the rectangles that describe what data is valid to access and what
+ data has been updated in this call. For all their additional complexity,
+ slice based decoding callbacks provide substantial speed gains to the
+ overall application in some cases, due to improved cache behavior.
+
+
+ \section usage_frame_iter Frame Iterator Based Decoding
+ If the codec does not support callback based decoding, or the application
+ chooses not to make use of that feature, decoded frames are made available
+ through the aom_codec_get_frame() iterator. The application initializes the
+ iterator storage (of type #aom_codec_iter_t) to NULL, then calls
+ aom_codec_get_frame repeatedly until it returns NULL, indicating that all
+ images have been returned. This process may result in zero, one, or many
+ frames that are ready for display, depending on the codec.
+
+
+ \section usage_postproc Postprocessing
+ Postprocessing is a process that is applied after a frame is decoded to
+ enhance the image's appearance by removing artifacts introduced in the
+ compression process. It is not required to properly decode the frame, and
+ is generally done only when there is enough spare CPU time to execute
+ the required filters. Codecs may support a number of different
+ postprocessing filters, and the available filters may differ from platform
+ to platform. Embedded devices often do not have enough CPU to implement
+ postprocessing in software. The filter selection is generally handled
+ automatically by the codec.
+
+
+*/