Poor man's timeshifting

G

Guest

Guest
Archived from groups: rec.video.desktop (More info?)

The application that came with my TV tuner/capture card offers a
timeshift feature, but for several reasons I'm not ecstatic about it.
In fact, depending on circumstances, I prefer to use VirtualDub to view
and capture.

Unfortunately VDub does not provide timeshifting capability, but, if I
could find a way to play a file while it is still being written, then I
have my timeshift feature, without the restrictions imposed by the
hardware's original application.

The capture card puts out your choice of MPEG1/2/4 (Dx50 or MP4S)
streams, hardware encoded.

The question: is it technically possible to play an open, incomplete
AVI? Are there any players that can do it? (WMP, MPC, VLC, Creative
Player, Roxio Player do not).

Thanks for any info.

---
We judge others by our own limitations.
 
G

Guest

Guest
Archived from groups: rec.video.desktop (More info?)

I haven't tried this, but I would be surprised if VideoLan Client (VLC)
could NOT do this. I have heard reports that it can play video as it
is being downloaded off the net, so unless these is some critical
information that is written to the file header at the END of the
process, I cannot see why this would not work.

cubicle281

bxf wrote:
> The application that came with my TV tuner/capture card offers a
> timeshift feature, but for several reasons I'm not ecstatic about it.
> In fact, depending on circumstances, I prefer to use VirtualDub to view
> and capture.
>
> Unfortunately VDub does not provide timeshifting capability, but, if I
> could find a way to play a file while it is still being written, then I
> have my timeshift feature, without the restrictions imposed by the
> hardware's original application.
>
> The capture card puts out your choice of MPEG1/2/4 (Dx50 or MP4S)
> streams, hardware encoded.
>
> The question: is it technically possible to play an open, incomplete
> AVI? Are there any players that can do it? (WMP, MPC, VLC, Creative
> Player, Roxio Player do not).
>
> Thanks for any info.
>
> ---
> We judge others by our own limitations.
 
G

Guest

Guest
Archived from groups: rec.video.desktop (More info?)

I also expected VLC to have some success, but no, it just wiggles
around a bit but does not provide any images. Maybe I can try to play
around with some of the options.

I'll have a look for "AVI Preview".

Thanks for the responses.

---
We judge others by our own limitations.
 
G

Guest

Guest
Archived from groups: rec.video.desktop (More info?)

bxf wrote:
<snip>
>
> The question: is it technically possible to play an open, incomplete
> AVI? Are there any players that can do it? (WMP, MPC, VLC, Creative
> Player, Roxio Player do not).
>
> Thanks for any info.
>
> ---
> We judge others by our own limitations.
>

An AVI file has an index (or several) that holds the adress for any
video fram or audio block. Using the index it is possible to access any
fram at random.
Using the index is therefore the normal way to read an AVI.

However, the structure of an AVI is such that normally it will be quite
possible to read it sequentially and find the video frames and audio
blocks in sequential order even without any index.

So, my answer would be: With some insight into the AVI file structure
and some programming skills, it *is* possible to play an incomplete AVI.
Searching will however not be possible.

I remember having seen a program that does, "AVI preview" or something
similar??

/JS
 
G

Guest

Guest
Archived from groups: rec.video.desktop (More info?)

>so unless these is some critical
> information that is written to the file header at the END of the
> process,

You bet there is!
 
G

Guest

Guest
Archived from groups: rec.video.desktop (More info?)

bxf wrote:
> I also expected VLC to have some success, but no, it just wiggles
> around a bit but does not provide any images. Maybe I can try to play
> around with some of the options.

In case anybody is interested: VLC will in fact play a file that is
still in the process of being written, if it is MPEG1 or MPEG2. It does
not seem to be able to cope with MPEG4.

---
We judge others by our own limitations.