From 43db9a8267823d7a8c46d7b8aafb43c0ad41173c Mon Sep 17 00:00:00 2001 From: The Android Open Source Project Date: Tue, 3 Mar 2009 19:30:49 -0800 Subject: auto import from //depot/cupcake/@135843 --- Tremor/doc/ov_read.html | 115 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 Tremor/doc/ov_read.html (limited to 'Tremor/doc/ov_read.html') diff --git a/Tremor/doc/ov_read.html b/Tremor/doc/ov_read.html new file mode 100644 index 0000000..208ef18 --- /dev/null +++ b/Tremor/doc/ov_read.html @@ -0,0 +1,115 @@ + + + +Tremor - function - ov_read + + + + + + + + + +

Tremor documentation

Tremor version 1.0 - 20020403

+ +

ov_read()

+ +

declared in "ivorbisfile.h";

+ +

+ This is the main function used to decode a Vorbis file within a + loop. It returns up to the specified number of bytes of decoded audio + in host-endian, signed 16 bit PCM format. If the audio is + multichannel, the channels are interleaved in the output buffer. + If the passed in buffer is large, ov_read() will not fill + it; the passed in buffer size is treated as a limit and + not a request. +

+ +Note that up to this point, the Tremor API could more or less hide the + multiple logical bitstream nature of chaining from the toplevel + application if the toplevel application didn't particularly care. + However, when reading audio back, the application must be aware + that multiple bitstream sections do not necessarily use the same + number of channels or sampling rate.

ov_read() passes + back the index of the sequential logical bitstream currently being + decoded (in *bitstream) along with the PCM data in order + that the toplevel application can handle channel and/or sample + rate changes. This number will be incremented at chaining + boundaries even for non-seekable streams. For seekable streams, it + represents the actual chaining index within the physical bitstream. +

+ +

+ + + + +
+
+long ov_read(OggVorbis_File *vf, char *buffer, int length, int *bitstream); +
+
+ +

Parameters

vf: A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisidec +functions.
buffer: A pointer to an output buffer. The decoded output is inserted into this buffer.
length: Number of bytes to be read into the buffer. Should be the same size as the buffer. A typical value is 4096.
bitstream: A pointer to the number of the current logical bitstream.

+ + +

Return Values

+
+
OV_HOLE
+
indicates there was an interruption in the data. +
(one of: garbage between pages, loss of sync followed by + recapture, or a corrupt page)
+
OV_EBADLINK
+
indicates that an invalid stream section was supplied to + libvorbisidec, or the requested link is corrupt.
+
0
+
indicates EOF
+
n
+
indicates actual number of bytes read. ov_read() will + decode at most one vorbis packet per invocation, so the value + returned will generally be less than length. +
+

+ +

Notes

Typical usage: +

+bytes_read = ov_read(&vf, +buffer, 4096,&current_section) +

+ +This reads up to 4096 bytes into a buffer, with signed 16-bit +little-endian samples. +

+ + + +

+

+ + + + + + + + +

copyright © 2002 Xiph.org	Ogg Vorbis
Tremor documentation	Tremor version 1.0 - 20020403

+ + + + -- cgit v1.2.3