VideoNow File Formats

[GregSmith]

Post here to discuss the technical details of creating VideoNow files

[Mr.Radar]

A well written bit on the VNCD format is at the PVDTools temperary homepage.

[Vampyre]

Hi guys. Im really not smart 'nuff to be posting over here so I'll keep it short.

Mr.Radar wrote:

Thank you. Integrating VirtualDub and cd-burning into my software is well beyond my ablities

I think a lot of freeware cd-burning apps use freeware command line utilities to do what they do, like cdrdao and mkisofs (some of the command line utils that burnatonce uses). seems like it would be easy
enough to have your program call these after it writes the wav files.

Would be very nice indeed to have this all in one application.

[Mr.Radar]

Mr.Radar wrote:

Thank you. Integrating VirtualDub and cd-burning into my software is well beyond my ablities

I think a lot of freeware cd-burning apps use freeware command line utilities to do what they do, like cdrdao and mkisofs (some of the command line utils that burnatonce uses). seems like it would be easy enough to have your program call these after it writes the wav files.

If you could tell me how to launch external programs from a C program I'd very gladly add that option. After I get a good working encoder/decoder I'll probabley right a GUI frontend for Windows(in VB) and if they're also supported under windows I'll include that functionality too.

@GregSmith:

In the format second of the .doc file you distribute with VideoThen(mirrored as a plain-text document here), you say that the sync data in the audio channel is a constant stream of 0x5a, but when I look at the raw timing data(from a file made with VideoThen) it is a stream of 0x00 for the first 2530 bytes, then it's 3200 bytes(same size as the actual video in a video frame) of 0xe1 then its 1600 bytes(1/2 size of video in a video frame) of 0x5a then its 670 bytes of 0xd2 and it seems to follow this patter(3200 0xe1, 1600 0x5a, 670 0xd2) for the rest of the file. As I'm planning the encoder right now, I need to know why this is.

[Vampyre]

Mr. Radar wrote:

If you could tell me how to launch external programs from a C program I'd very gladly add that option

No clue. I write for dos, not windows. yeah i know, i'm living in the past blah blah. In djgpp, which is for dos, the command is spawnl . But thats
not portable in any way.. Maybe its time i learn to code for windows. *shudder*

[Mr.Radar]

I am actually using DJGPP to write this. Thanks for the tip!

[GregSmith]

mr radar wrote:

In the format [section] of the .doc file you distribute with VideoThen(mirrored as a plain-text document here), you say that the sync data in the audio channel is a constant stream of 0x5a, but when I look at the raw timing data(from a file made with VideoThen) it is a stream of 0x00 for the first 2530 bytes, then it's 3200 bytes(same size as the actual video in a video frame) of 0xe1 then its 1600 bytes(1/2 size of video in a video frame) of 0x5a then its 670 bytes of 0xd2 and it seems to follow this patter(3200 0xe1, 1600 0x5a, 670 0xd2) for the rest of the file. As I'm planning the encoder right now, I need to know why this is.

i will have to get back to you on this. but i'm pretty sure that the audio track is just 0x5a data.

from my manual:

The audio track is also preceeded by 2531 bytes of 0x00. Note that this is precisely 1/2 the number of bytes of the video header's 0x00s. Remember that the audio track is composed of 8-bit values for the audio and some sync data? Well the sync data is a constant stream of 0x5a.

hope this helps...

oh, and to spawn a command from 'C' - use either the system() function or one of the exec() functions

[Bigjohn_s]

A well written bit on the VNCD format is at the PVDTools temperary homepage.

nothing there.

[Mr.Radar]

Reclick the link in my original post, it should be working now.