From 3785cdbea4cd5058157420fb5a839e01c3547d3f Mon Sep 17 00:00:00 2001
From: David Schleef <ds@schleef.org>
Date: Fri, 14 May 2004 20:06:49 +0000
Subject: [PATCH] found these somewhere

Original commit message from CVS:
found these somewhere
---
 docs/random/ds/buffer_locking | 30 ++++++++++++++++
 docs/random/ds/caps           | 81 +++++++++++++++++++++++++++++++++++++++++++
 docs/random/ds/categories     | 50 ++++++++++++++++++++++++++
 3 files changed, 161 insertions(+)
 create mode 100644 docs/random/ds/buffer_locking
 create mode 100644 docs/random/ds/caps
 create mode 100644 docs/random/ds/categories

diff --git a/docs/random/ds/buffer_locking b/docs/random/ds/buffer_locking
new file mode 100644
index 0000000..8200a81
--- /dev/null
+++ b/docs/random/ds/buffer_locking
@@ -0,0 +1,30 @@
+
+
+Buffers should have readlocks and writelocks to enforce
+GST_BUFFER_DONTKEEP and relax the restriction that buffers with
+multiple refcounts are read-only.
+
+
+
+Example:
+
+  videotestsrc ! ximagesink
+
+  videotestsrc requests a buffer from its src pad
+
+  ximagesink creates a buffer (refcount:1 readlock:0 writelock:0)
+
+  videotestsrc writelocks it (refcount:1 readlock:0 writelock:1)
+
+  videotestsrc writes to the buffer
+
+  videotestsrc un-writelocks it (refcount:1 readlock:0 writelock:0)
+
+  ximagesink readlocks it (refcount:1 readlock:1 writelock:0)
+
+  ximagesink writes it to the screen
+
+  ximagesink un-readlocks it (refcount:1 readlock:0 writelock:0)
+
+
+  
diff --git a/docs/random/ds/caps b/docs/random/ds/caps
new file mode 100644
index 0000000..bc011d0
--- /dev/null
+++ b/docs/random/ds/caps
@@ -0,0 +1,81 @@
+
+
+Problem #1:
+
+  How does the core allow the application to choose appropriate
+  caps in the following cases:
+
+    videotestsrc ! xvimagesink
+
+    videotestsrc ! identity ! xvimagesink
+
+    videotestsrc ! videoscale ! xvimagesink
+ 
+  Goals:
+  
+  - Give the application a clear overview of the formats available
+    and the elements involved.
+
+  - Provide reasonable defaults in as many cases as possible.
+
+  - Allow specialized elements to suggest reasonable defaults.
+
+
+
+Problem #2:
+
+  How does the API express to an autoplugger what an element does?
+
+  Currently, "colorspace" and "videoscale" have approximately the
+  same pad template caps.  Until the autoplugger plugs and looks,
+  it has no way to determine that colorspace changes format, and
+  videoscale changes size.
+
+
+
+Problem #3:
+
+  How do we properly handle codec metadata?
+
+  Solution #3a:
+
+    Stream initialization event.  This event would be held by all
+    src pads, and pushed to sink pads upon connection, and would
+    flow downstream.
+
+  Solution #3b:
+    
+    Put a buffer in the caps.
+
+
+Problem #4:
+
+  (Related to #1) How does one specify that a converter should limit
+  it's conversion?  I.e., audioconvert to not change number of channels,
+  or audioscale upsample by 20%.  Basically, this means caps based on
+  other caps.
+
+  Solution #4a:
+
+    One can put a converter element into a special bin:
+
+      specialbin.( specialidentity ! converter ! specialidentity )
+
+    Specialbin can then interfere with caps negotiation all it wants.
+
+
+Problem #5:
+
+  (Related to #3)  How do we specify stream format information that
+  is non-critical and optional, such as pixel aspect ratio on raw
+  video?
+
+Problem #6:
+
+  How do we specify the difference between nominal values and actual
+  values, such as video frame rate?  The actual frame rate may not
+  correspond to the nominal frame rate in the caps, and often a guess
+  is listed.
+
+
+
diff --git a/docs/random/ds/categories b/docs/random/ds/categories
new file mode 100644
index 0000000..2636f11
--- /dev/null
+++ b/docs/random/ds/categories
@@ -0,0 +1,50 @@
+
+Element Categories:
+-------------------
+
+
+Decoder:
+
+
+Encoder:
+
+
+Converter:
+ A converter has one or more source pads and one or more sink pads.
+ Converter pads may have different caps templates.  Converters are
+ expected 
+
+
+Filter:
+ A filter has one source and one sink pad.  These pads have the same
+ caps and (thus) the same caps template.
+
+ Filters generally do not handle events.
+
+ Filters may have interfaces.
+
+ Filters are generally not autoplugged unless they have interfaces.
+
+
+Source:
+ A source has one source pad and no sink pads.
+
+ Sources usually handle events.
+
+ Sources may have interfaces.
+
+ Sources are not autoplugged.
+
+Sink:
+ A sink has one sink pad and no source pads.
+
+ Sources usually handle events.
+
+ Sources may have interfaces.
+
+ Sinks are not autoplugged.
+
+
+
+Converter/Colorspace
+
-- 
2.7.4