NSV Streaming Media

sweetnuts

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when i try to download the files the video is choppy and super fast. does anyone know what wrong?

Wannabe
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Well, sort of. I don’t know exactly what is wrong, but AOL has made the videos so they only play from the streaming server. Once they are downloaded, they are unplayable. Here are some of the possible reasons that I can think of:

1. The downloaded video is missing some data. The server supplies it only when streaming.

2. The downloaded video is corrupted slightly. When streaming, the server provides information or authorization to “un-corrupt” the video.

3. Part of the video is encrypted (similar to DVD technology). The decryption code is supplied when streaming, but does not get saved in the file.

4. The video makes use of session variables which authorize it to play only while the streaming connection is active.

5. The video contains an embedded link. Winamp only authorizes it to play if it is playing from that Internet location.

Remember these are just ideas. I don’t really know what AOL has done to the videos. Right now their extensive video library is protected by obscurity. The system itself is very “open," meaning it could be easily hacked, but nobody knows exactly how the streaming technology works.

Right now we are fortunate that AOL has not implemented any of the following protections:

1. Member-only access.

2. Dynamic URLs.

3. “Uncrackable” DRM technology similar to that created by Microsoft.

4. Removing all QT and RM copies.

-Steve

NSV_Format

Guest

The NSV/NSA format uses time signals sent from the server to make sure that the timing is correct. wqithout them it plays back at maximum speed.

Wannabe
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NSV_Format,

What you said is very interesting to me. Where did you get this information? I’d love to have any more help you can provide! :-)

I’ve been hacking through an NSV file to see if I can figure out what the problem is. It seems that after every 4 to 30 chunks (maybe more, maybe less, I haven’t looked at enough files yet) of data (aka “BEEF”, there is an extra/unexpected 7 bytes. This obviously breaks the file format from the published specification.

I tried demuxing the audio stream and appending the extra 7 bytes to it each time the extra shows up. This seems to improve the audio stream to the point that it sounds almost correct with Winamp’s smooth AAC decoder, but I think it’s still missing some data.

Hmm... I wonder if I can get a working file if I read the data directly out of the incoming packets. The trouble is, I don’t really know anything about packet formatting.

Here is a dump from my hack attempts on one file:

NSVs at byte 1 Video 4CC: VP50 Audio 4CC: AAC Video Width: 320
Video Height: 240 Framerate: 129 Unknown 1: 0 Unknown 2: 0
Video chunk size: 34 Audio chunk size: 0
Found BEEF at 59 Video chunk size: 93 Audio chunk size: 970
Found BEEF at 1129 Video chunk size: 767 Audio chunk size: 368
Found BEEF at 2271 Video chunk size: 2638 Audio chunk size: 380
Found BEEF at 5296 Video chunk size: 2380 Audio chunk size: 380
Found BEEF at 8063 Video chunk size: 2296 Audio chunk size: 382
Found BEEF at 10748 Video chunk size: 2521 Audio chunk size: 387
Found BEEF at 13663 Video chunk size: 2411 Audio chunk size: 389
Found BEEF at 16470 Video chunk size: 2250 Audio chunk size: 360
ERROR: BEEF not found where expected at byte 19087
BEEF found unexpectedly at byte 19094
Video chunk size: 2174 Audio chunk size: 389
Found BEEF at 21664 Video chunk size: 1787 Audio chunk size: 395
Found BEEF at 23853 Video chunk size: 1803 Audio chunk size: 392
Found BEEF at 26055 Video chunk size: 1835 Audio chunk size: 370
Found BEEF at 28267 Video chunk size: 1914 Audio chunk size: 397
Found BEEF at 30585 Video chunk size: 2276 Audio chunk size: 375
Found BEEF at 33243 Video chunk size: 2340 Audio chunk size: 389
Found BEEF at 35979 Video chunk size: 1769 Audio chunk size: 377
Found BEEF at 38132 Video chunk size: 1858 Audio chunk size: 380
ERROR: BEEF not found where expected at byte 40377
BEEF found unexpectedly at byte 40384
Video chunk size: 2156 Audio chunk size: 381
Found BEEF at 42928 Video chunk size: 2012 Audio chunk size: 374
...

linux_newbie

Guest

So i had the same problems. After managing to download a .nsv video to my hard drive, winamp would play it like x100 times faster.

But then that was yesterday in Windows. Today (after installing Linux for the first time) i remembered this problem and just googled sth like 'linux .nsv playback'.

Xine was the answer i found, so i fired it up and tried to play the .nsv video i had downloaded.

Well, it played back almost flawlessly. The only problem was some jitter in the sound which i don’t know where it can be attributed.

It can be the source audio, it can also be my crappy speakers. Or it could be the 'chunks out of specs' aol patend mentioned above...

Wannabe
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How fascinating... I will have to try that. I went to the Xine page and saw that a Windows version is still in the works. So I guess either I’ll have to install Linux on one of my machines or I must wait until the Windows version is complete.

I noticed on the Xine features page that the NSV container format is supported. So is VP3 video and AAC audio. However, I did not see VP5 video listed. VP5 is the video codec used in the 'broken' NSV videos. I don’t understand why Xine can play them, unless it contains additional decoders not listed on the features page. Either way I’m very interested in Xine now! :-)

Entree
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Joined: 12 May 2005
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hi
I am new to this forum having just Googled here in the hope of finding a solution to my .nsv streaming problem.
I am operating on a Mac OSX system and I need to find an application that allows streaming .nsv formats.
Winamp appears to be the only one and it operates well on a PC but unfortunately even the Mac version WinampMac v0.71 will not stream.
Can anyone offer any helpful suggestions???

linux_newbie

Guest

On2 VP5 is the codec reported by xine on the .nsv i tested (and which winamp couldn’t play).

So i guess it is supported after all (xine 0.99.3)

BTW, u don’t have to install linux to verify this. Just download a Live CD Linux distribution (like KNOPPIX) which has xine...

Xcutioner

Guest

hi I wanna know how do u get the link/address of the nsv file from winamp???

jeffrey

Guest

hi, i’m trying to stream a *.nsv file in winamp but when i click play it stops and says “connecting to server” and when i hit play again it comes up saying "*.nsv?" what is my problem and how can i fix it?

nsvhack

Guest

Can I wake up this thread?

Everyone may be going about this nsv problem the wrong way. You know you can download the full .nsv data file. It just doesn’t play back correctly.

From what I understand, there is no timing information in the .nsv file itself. The reason is plays correctly in winamp while streaming is that the server regulates the speed at which the data is transfered to the player. So when you have the file downloaded locally on your hard drive it plays way too fast.

What someone needs to do is to dive into the .nsv file format and TRANSLATE it into a more friendly format (i.e AVI or MPEG).

Wannabe
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Joined: 21 Apr 2005
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nsvhack, I think you’re on the right track! However, I do believe the file is actually “broken” somehow, since nsvdemux won’t work on these files and mplayer gives a million error messages. It is possible (and likely) that AOL changed the file format slightly from the original published specs, which could account for the strange behavior.

Does anybody know if the NSV container format is patented? If so, it would be legally unwise to try to reverse-engineer it. But if it’s not patented, I would love for somebody to try to write a demuxer for NSV that actually works on the AOL files! It would be a big step in the right direction. Of course, AOL might get ticked-off and modify the file format again. :-( Somebody over there probably reads this thread just to see how we’re coming along.

If we can figure out how to demux the NSV, then it would be a simple proposition to remux it into an AVI. But then we’ve got the new problem of obtaining filters for VP50 video and AAC audio. Obviously Xine and some other players have these filters. But is there a VFW filter for VirtualDub? Or maybe a DirectShow filter for AVISynth? I don’t have the answers to these questions yet.

If there is a VP50 filter that works with AVISynth, I’d like to know about it. If you can get video into AVISynth, then you can load it into VirtualDub or TMPGEnc. From there, the sky is the limit... you can transcode into any “friendly” format.

Vespian

Guest

Reverse-Engineering the .nsv file format would be a simple (but very complex) step in the right direction to finding a solution to our little problem. However, you are correct to worry about the legal implications of doing so. I would check into seeing as to whether or not the .nsv container is patented, and if it is, find out exactly whom owns the patent. Either way, if we succeed, the .nsv container is only going to be improved once again to make it “unhackable”. (But isn’t that the fun of it? After all, we could very easily download the vids in other formats...) Good Luck! Nothing Is Unhackable.

Yogesh

Guest

AOL uses ultravox servers for media streaming i.e. streaming of nsv files. This server uses on-the-fly encryption. i.e. the data is encrypted and can be decripted by some keyblock guid.

Well for more information of how the ultravox server works you can actually download the official Ultravox3 Protocol Specification.pdf file from
http://ultravox.aol.com/Ultravox3.pdf
please if you can find a way to hear these files.let me know. I am also trying in the same direction.
Also the ultravox sever is for unix platform and also a freeware and can be downloaded at http://ultravox.aol.com

Wiley

Guest

Hi Guys
I don’t know if this is of any use to you fella’s...

I’ve been able to capture NSV and replay it with no problems. I paste the url of the stream e.g.
http://xx.xx.xx.xxx:xxxx;stream.nsv
into a programme called “HiDownload” which captures the stream. The stream is saved as an mp3 file, so after capture I change the file ext from .mp3 to .nsv, it plays back in winamp fine.

I have a 2.5mb .nsv sample that I kept for testing purposes

Cheers
Ray

Abhay

Guest

but what about videos it finiushes with in fraction of second

Wannabe
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Joined: 21 Apr 2005
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Yogesh, you are my hero! Thank you for the link to ultravox.aol.com. AOL is being very generous by not only providing a full specification (http://ultravox.aol.com/NSVFormat.rtf), but also providing a patent license that gives us FULL PERMISSION to make our own implementations! Yay! I’m going to dig into the spec when I have the free time... hopefully I’ll find the golden nugget I’ve been searching for. :-)

Michele

Guest

For Wiley. Where did you find the url of the video? I tried with Mozilla but I didn’t find it. And also, which url did you exactly put in HiDownload? Also with ":stream.nsv” ?

Guest of Guests

Guest

How do u change your Agent ID? which program are u referring to in order to download mms, rtsp or just http media?

thanks

Guest of Guests

Wiley

Guest

@Michele

In the Winamp menu, select “View File Info” that will give you the required url to paste into your preferred downloader, I use a programme called “HiDownload”. To find the url from within a web-browser, you will need to view the “Source” of the page you have loaded, in IE select “View” then “Source”, it may take a bit of looking to find it

Cheers
Wiley