Outline · [ Standard ] · Linear+ A faster video preview way

[NicoVR]

I think there are more and more fake video files. To download the right parts to preview by default can break the fast spreading.

So, is there an easy way to implement a random snapshot or to convert an I frame or equivalent to a still JPEG picture? 3 or 4 of them should help a little to know about the content.

It may be very difficult to read the stream in the parts of files, and protocol doesn't support it. I have thought of an emule colecction or so, but that can be fakable too.

Any idea?

[Fuxie - DK]

Nope.. Sorry.. There isn't..

- MPGs can be previewed at soon as 180KB is downloaded anywhere in the file (this causes the Preview-option fo become available..
- AVIs can be previewed when the last chunk, and 60KB (I think) of the first chunk is downloaded. This is because AVIs contain a lot of header info that needs to be available..

[Vladimir (SV)]

Well, I like the idea, that could be a preview Plus ^^

let say -to not disrupt eD2K protocol- that can work only between eMule Plus clients, and they can request thumbnails from a video (of course, ePlus would create them when full video is downloaded).

Those might be JPEG low-quality pictures, just to give a general idea of the veracity of the content being downloaded.

That would not be more than a few KBs per movie and would be extremely nice to see thumbnails in the comment reader or file info =)

In general, I like this idea.

[muleteer]

Sigh! The thumbnail could be faked too. GRRR!!!

[Vladimir (SV)]

If they're auto generated no, they will have to edit them manual, and normal people does not do that.

[muleteer]

Yes, but the damn fake spreaders aren't normal people.

As far as possible, get your links from a good ed2k release site. I very rarely add links from anywhere else.

[NicoVR]

Yes, that is the best.
I use the built-in server search a lot. Then I would like something in that way.

I see it is not easy at all.

I think there must be something anyway.

index is needed for seeking. If we know where to start we only need the header, don't we?
Can emule make custom parts? Header part and parts that don't break frames.

[muleteer]

If you use VLC for preview along with the partfile plugin, you can get a very good preview after downloading only a couple of MBs. We already have the option to get first/ last chunks for preview; about 369KB of the first chunk enables the preview - get a little bit more and you'll get visible frames.

For files that are not deliberate fakes - designed especially for disrupting the spread of a file - keep a close eye on the file names that other clients are using. You get useful information from that.

[glaskrug]

I noticed that with the last 2 or so version of VLC, preview is not as it used to be before.
Many files are not scrollable (instead you get a dialog asking if you want to fix the index...).

Do you know if there is a way to tweak the preview code so that it downloads a bit more of the file, so that VLC is happy with the index and you can properly preview incomplete files (again).

(I know, I could step back to older VLC versions, but there are nice things in later versions I don't wanna miss either...)

P.S.: unfortunately it seems that a partfile plugin for 0.8.6(a) won't show up in the near future
( http://forum.emule-project.net/index.php?s...ndpost&p=844860 )

[muleteer]

This is bad news. The only reason I even heard of VLC was because of the preview for eMule feature. They will lose a big portion of their userbase without that. Me, I'm going back to v0.8.4. Had enough of the 'file is broken' messages.

[DonGato]

You have Zoom Player (Professional) and Media Player Classic.

[pant]

since almost all videos are encoded with mpeg4 nowadays, and all mpeg4 codecs use standard mpeg4 start codes for i- and p-frames, it is trivial to scan downloaded chunks for i-frame start codes and decode the frame there. this is regardless of whether or not you have the start, end or correct container.

all this method needs is an mpeg4 codec used, a container that doesn't split up individual frame chunks (that will cover all popular containers), and an mpeg4 i-frame decoder in eplus (mpeg4 i-frames are very simple to decode).

the method of scanning for i-frame start codes is how one of the avipreview programs (there are several with the same name) lets you decode and view partial files without needing the start or end of the file. if you're just interested in i-frames, you can make this method container-agnostic.

[muleteer]

Very interesting. Do you have some links to reference material?

[Fuxie - DK]

since almost all videos are encoded with mpeg4 nowadays, and all mpeg4 codecs use standard mpeg4 start codes for i- and p-frames

What about older videos??
There are still TONS of them out there..

[muleteer]

We'll continue with the method we use now. But for new videos, if we can do better, we should.