about WMA audio stream, what does "Codec Specific Data" mean
WMPTalk.com Forum Index WMPTalk.com
Discuss Windows Media Player
 
 FAQFAQ   MemberlistMemberlist     RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 
Google
 
Web wmptalk.com
about WMA audio stream, what does "Codec Specific Data" mean

 
Post new topic   Reply to topic    WMPTalk.com Forum Index -> SDK
Author Message
dspshin
Guest





Posted: Fri Sep 17, 2004 12:00 pm    Post subject: about WMA audio stream, what does "Codec Specific Data" mean Reply with quote

below is parsed information by windows media asf view 9 series program
=======================================================================
Stream Properties Object [1] (114 bytes)
=======================================================================

Property Value
-----------------------------------------------------------------------
File Position || 2162 ( 0x872 )
Object ID || B7DC0791-A9B7-11CF-8EE6-00C00C205365
Object Size || 114 ( 0x72 )
-----------------------------------------------------------------------
Stream Number || 1
Version || 1
Offset || 0
Encrypted || False
Security ID || 421789336 ( 0x1923FE98 )
----------------------------------------------------------------------
Stream Type Specific
----------------------------------------------------------------------
Stream Type || Audio Media
Format Tag || 353
Channels || 2
Samples / Seconds || 48000
Average Bytes / Second || 16018
Average Bitrate (bits/sec) || 128144
Block Align || 5462 ( 0x1556 )
Bits / Sample || 16
Extra Data Size || 10
Extra Data 0000: || 00 88 00 00 0F 00 59 55-00 00
=======================================================================

i can understand upper information but i can't understand exactly
about Extra Data

in "Advanced Systems Format (ASF) Specification Document"
Extra Data is explained ....Codec Specific Data Specifies an array of
codec-specific data bytes...

i guess that Extra Data is

typedef struct {
WAVEFORMATEX Format;
~~~~~~~~~~~~~~ Extra Data start ----> ~~~~~
union {
WORD wValidBitsPerSample;
WORD wSamplesPerBlock;
WORD wReserved;
} Samples;
DWORD dwChannelMask;
GUID SubFormat;
<---------- Extra Data end ~~~~~~~~~~~~~

} WAVEFORMATEXTENSIBLE, *PWAVEFORMATEXTENSIBLE;

but actully does not matched between Extra Data and (00 88)(00 00)(0F
00)(59 55-00 00)
wValidBitsPerSample .........??
wSamplesPerBlock; .........??
wReserved; .........??
dwChannelMask..??
is there any one who explain about Extra Data or "Codec Specific Data"
in ASF file format(about wma audio stream)..

thank for your regard...

Back to top
Alessandro Angeli [MVP::D
Guest





Posted: Fri Sep 17, 2004 1:01 pm    Post subject: Re: about WMA audio stream, what does "Codec Specific Data" Reply with quote

"dspshin" <dspshin@mediaworks.co.kr> wrote:

Quote:
is there any one who explain about Extra Data or "Codec Specific Data"
in ASF file format(about wma audio stream)..

The Codec Specific Data used by the WMA codec is undocumented: as the naming
suggests, it is data only the codec knows about and is completely opaque
unless you have specific information about the codec (and none is available
about the WMA codec).


--

Alessandro Angeli

MVP::DigitalMedia

a dot angeli at biosys dot net
Back to top
 
Post new topic   Reply to topic    WMPTalk.com Forum Index -> SDK All times are GMT
Page 1 of 1

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Microsoft Office Forum New Topics
Powered by phpBB