1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
2<HTML
3><HEAD
4><TITLE
5>Codec Interface</TITLE
6><META
7NAME="GENERATOR"
8CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
9REL="HOME"
10TITLE="Video for Linux Two API Specification"
11HREF="book1.htm"><LINK
12REL="UP"
13TITLE="Interfaces"
14HREF="c6488.htm"><LINK
15REL="PREVIOUS"
16TITLE="Video Output Overlay Interface"
17HREF="x6909.htm"><LINK
18REL="NEXT"
19TITLE="Effect Devices Interface"
20HREF="x7002.htm"></HEAD
21><BODY
22CLASS="SECTION"
23BGCOLOR="#FFFFFF"
24TEXT="#000000"
25LINK="#0000FF"
26VLINK="#840084"
27ALINK="#0000FF"
28><DIV
29CLASS="NAVHEADER"
30><TABLE
31SUMMARY="Header navigation table"
32WIDTH="100%"
33BORDER="0"
34CELLPADDING="0"
35CELLSPACING="0"
36><TR
37><TH
38COLSPAN="3"
39ALIGN="center"
40>Video for Linux Two API Specification: Revision 0.24</TH
41></TR
42><TR
43><TD
44WIDTH="10%"
45ALIGN="left"
46VALIGN="bottom"
47><A
48HREF="x6909.htm"
49ACCESSKEY="P"
50>Prev</A
51></TD
52><TD
53WIDTH="80%"
54ALIGN="center"
55VALIGN="bottom"
56>Chapter 4. Interfaces</TD
57><TD
58WIDTH="10%"
59ALIGN="right"
60VALIGN="bottom"
61><A
62HREF="x7002.htm"
63ACCESSKEY="N"
64>Next</A
65></TD
66></TR
67></TABLE
68><HR
69ALIGN="LEFT"
70WIDTH="100%"></DIV
71><DIV
72CLASS="SECTION"
73><H1
74CLASS="SECTION"
75><A
76NAME="CODEC"
77>4.5. Codec Interface</A
78></H1
79><DIV
80CLASS="NOTE"
81><BLOCKQUOTE
82CLASS="NOTE"
83><P
84><B
85>Suspended: </B
86>This interface has been be suspended from the V4L2 API
87implemented in Linux 2.6 until we have more experience with codec
88device interfaces.</P
89></BLOCKQUOTE
90></DIV
91><P
92>A V4L2 codec can compress, decompress, transform, or otherwise
93convert video data from one format into another format, in memory.
94Applications send data to be converted to the driver through a
95<A
96HREF="r14496.htm"
97><CODE
98CLASS="FUNCTION"
99>write()</CODE
100></A
101> call, and receive the converted data through a
102<A
103HREF="r14264.htm"
104><CODE
105CLASS="FUNCTION"
106>read()</CODE
107></A
108> call. For efficiency a driver may also support streaming
109I/O.</P
110><P
111>[to do]</P
112></DIV
113><DIV
114CLASS="NAVFOOTER"
115><HR
116ALIGN="LEFT"
117WIDTH="100%"><TABLE
118SUMMARY="Footer navigation table"
119WIDTH="100%"
120BORDER="0"
121CELLPADDING="0"
122CELLSPACING="0"
123><TR
124><TD
125WIDTH="33%"
126ALIGN="left"
127VALIGN="top"
128><A
129HREF="x6909.htm"
130ACCESSKEY="P"
131>Prev</A
132></TD
133><TD
134WIDTH="34%"
135ALIGN="center"
136VALIGN="top"
137><A
138HREF="book1.htm"
139ACCESSKEY="H"
140>Home</A
141></TD
142><TD
143WIDTH="33%"
144ALIGN="right"
145VALIGN="top"
146><A
147HREF="x7002.htm"
148ACCESSKEY="N"
149>Next</A
150></TD
151></TR
152><TR
153><TD
154WIDTH="33%"
155ALIGN="left"
156VALIGN="top"
157>Video Output Overlay Interface</TD
158><TD
159WIDTH="34%"
160ALIGN="center"
161VALIGN="top"
162><A
163HREF="c6488.htm"
164ACCESSKEY="U"
165>Up</A
166></TD
167><TD
168WIDTH="33%"
169ALIGN="right"
170VALIGN="top"
171>Effect Devices Interface</TD
172></TR
173></TABLE
174></DIV
175></BODY
176></HTML
177>
178