IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Index marks in WMA file
moonshot
post Aug 31 2010, 11:08
Post #1





Group: Members
Posts: 55
Joined: 31-May 04
Member No.: 14428



If I move WMA files from my dictation machine to my PC, is there a way to modify the index marks?

Here is some background info: I have an WS-331M Olympus dictation machine which only records in WMA. (It encodes using regular WMA, rather than WMA Voice). The dictation machine lets the user create index marks at different places in the recording which can later be used to skip during playback. If I transfer the WMA audio file to my PC, is there a way to see or to change these index marks?

If I recall correctly, WMA is stored inside an ASF container. I would guess that it is the container which provides extra functionality such as index marks. If this ASF index function is standard then maybe there's a way to view or edit those index marks.

Can you suggest any tools or techniques to try?

Thank you.

PS. This is a link to info about the recorder: Official Olympus site about WS-331M

This post has been edited by greynol: Aug 31 2010, 18:36
Reason for edit: Removed post icon. This discussion is no more important than anyone else's.
Go to the top of the page
+Quote Post
saratoga
post Aug 31 2010, 15:33
Post #2





Group: Members
Posts: 4718
Joined: 2-September 02
Member No.: 3264



I've never heard of this feature in ASF, so my guess is that the marks are not written to the file, but I could be wrong.
Go to the top of the page
+Quote Post
Liandril
post Sep 7 2010, 01:51
Post #3





Group: Members
Posts: 5
Joined: 27-August 10
Member No.: 83419



QUOTE (moonshot @ Aug 31 2010, 12:08) *
If I recall correctly, WMA is stored inside an ASF container. I would guess that it is the container which provides extra functionality such as index marks. If this ASF index function is standard then maybe there's a way to view or edit those index marks.

The ASF Specification contains an incredible amount of Objects, among them are several "Index Objects". Could you upload a sample file containing index marks? Then I could look into the file and maybe I can tell you then, if and which index objects are used. If you want to do it by yourself, you need to load a sample file into a HexEditor and search for the GUIDs of the index objects (these can be found in the ASF specification). But I don't know about a program that is capable of handling those index objects sad.gif
Go to the top of the page
+Quote Post
moonshot
post Sep 7 2010, 11:59
Post #4





Group: Members
Posts: 55
Joined: 31-May 04
Member No.: 14428



QUOTE (Liandril @ Sep 6 2010, 16:51) *
The ASF Specification contains an incredible amount of Objects, among them are several "Index Objects". Could you upload a sample file containing index marks? Then I could look into the file and maybe I can tell you then, if and which index objects are used. If you want to do it by yourself, you need to load a sample file into a HexEditor and search for the GUIDs of the index objects (these can be found in the ASF specification). But I don't know about a program that is capable of handling those index objects sad.gif


Liandril, I followed your interesting link to the Microsoft info on ASF and installed their ASF Viewer ("Windows Media ASF View 9 Series"). The viewer very neatly shows a view of fascinating information about an ASF or WMA file. I couldn't find anything which related to index marks but there is some much info that I haven't checked it all out. It seems that the entry for "flags" (in File Properties Object) is for something else.

I also looked at the Microsoft ASF specifications document which I found using your link. It seems there is something called a Seekable Flag which is used to indicate that a file contains Index Objects. This is all a bit beyond my capabilities but it does suggest there is a standard way of indexing the file with Index Objects. Maybe, just maybe, some audio or multimedia editor actually permits the index marks to be easily manipulated.

I will upload a sample audio file for you to look at. Can I upload it to this forum or do I have to upload it to the Uploads Forum?


Moonshot
Go to the top of the page
+Quote Post
Liandril
post Sep 7 2010, 13:11
Post #5





Group: Members
Posts: 5
Joined: 27-August 10
Member No.: 83419



Hi Moonshot,
QUOTE (moonshot @ Sep 7 2010, 12:59) *
Liandril, I followed your interesting link to the Microsoft info on ASF and installed their ASF Viewer ("Windows Media ASF View 9 Series").
Oh, thanks - I never noticed the ASF viewer. It looks indeed very helpful smile.gif

QUOTE (moonshot @ Sep 7 2010, 12:59) *
The viewer very neatly shows a view of fascinating information about an ASF or WMA file. I couldn't find anything which related to index marks but there is some much info that I haven't checked it all out. It seems that the entry for "flags" (in File Properties Object) is for something else.
...
I also looked at the Microsoft ASF specifications document which I found using your link. It seems there is something called a Seekable Flag which is used to indicate that a file contains Index Objects.

I don't know anything about all the other objects, but I'm quite familiar with the File Properties Object, Stream Properties Object, (Header Extension Object) and Data Object, because these 4 objects HAVE to be in every wma file. I know that, because last month, I tried to write a program that creates .wma Files on its own (rather impossible). So I'm sorry, but for the 'Seekable Flag': this is always set in wma files (with one audio stream, as in your case). A .wma file with seekable flag set does not need to have an Index Object. And without any special Objects for indexing, there seems to be no standard indexing ... well, the Data Object is divided into Data Packets (=these could be used as "jump points"), but when a file has only the 4 objects mentioned , then there is no such thing as a standard index table or markers, as far as I know.
So I think for index marks, there should be an Index Object or the "Marker Object" in your file. Especially the "Marker Object" seems to provide exactly the function that you describe:
"Marker Object: Provides named jump points within a file."

QUOTE (moonshot @ Sep 7 2010, 12:59) *
I will upload a sample audio file for you to look at. Can I upload it to this forum or do I have to upload it to the Uploads Forum?


unsure.gif Oh...sorry, but I don't know. I'm rather new to this forum.
And sorry for my English... I hope you're able to guess what I mean wink.gif

This post has been edited by Liandril: Sep 7 2010, 13:15
Go to the top of the page
+Quote Post
Liandril
post Sep 7 2010, 13:37
Post #6





Group: Members
Posts: 5
Joined: 27-August 10
Member No.: 83419



Hmm... I just found something, maybe it helps/works: The Windows Media Player contains a functionality for playing files that contain markers. I've the german version so I try to guess the english names: In menu "View" there's a submenu "(File) Markers"... this should be available if a file contains markers. Choosing one of the markers should (according to the help function) play the file from the marked point.
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 24th April 2014 - 06:25