Avisynth virtual file system

[Adub]

Okay, so it IS my network. Let me see if I can find a gigabit card for my laptop.

[Shinigami-Sama]

actually
cold the fake AVI file be passed off to a http server? I don't see why not
you could easily have a script pass it off to a lossless encoder
though I guess that might not work for some applications...

[IanB]

People need to consider the data being virtualized here is big, really big. A RGB24 1920x1080 24fps progressive stream is 149,299,200 bytes per second. Even a YV12 (4:2:0) 720x480 60i is still 15,552,000 bytes per second. This is 24% more than the theoretical maximum transfer of a 100Mb/s ethernet (probably more than twice the practical throughput). These numbers are even a small chunk out of a 800MHz FSB memory channel at around 6,400,000,000 bytes per second.

[joe48]

Lossless compression in AVFS is not a solution to network bandwidth problems. AVFS would need to preprocess (compress) all frames to figure out file layout and indexing. It would make more sense to skip AVFS and losslessly encode to a real AVI file.

Serving over a network is still useful when the CPU overhead of the script and encoder are limiting throughput below what the network can handle.

[Adub]

Yeah, this is making more and more sense. Looks like I have a nice project to work on over the summer! I just need to setup a decent gigabit network, and look at my filter chain to see if I can change the bottleneck to be the avs, not my network.

[Zarxrax]

I've found a very strange bug. I have a folder full of a few hundred avisynth scripts, and all of them contain the line
AssumeFPS("ntsc_double")
I was going through mounting each one, one at a time, and i noticed that some of them would mount fine, but when i tried to mount others, it would crash. On these that failed to mount, I discovered that I could get them to mount by simply removing the AssumeFPS line. That's really strange though, since all of my scripts have that line, and some of them work. I've determined that it is this specific line that it causing it to crash though, in many of my scripts.

[joe48]

Originally Posted by Zarxrax

I've found a very strange bug. I have a folder full of a few hundred avisynth scripts, and all of them contain the line
AssumeFPS("ntsc_double")

If you can get me a sample exhibiting the problem I can look at it. Send me a PM.

[morsa]

Could something simillar to "FireHose" from Cinelerra be modified for our uses?

[Quark.Fusion]

About compression on network: did someone tried open share over compressed vpn link?

[Quark.Fusion]

Also about networking with avisynth: avisynth already have networking functionality with TcpServer(), will it work with mounted file?

What about adding multithreaded Lagarith compression for networking to AVFS? For user this can look like adding two variables to avs file with port number and compression method (like in TcpServer), on other side user will mount special file, that will re-create avi file in virtual filesystem (like using TcpSource). Of course all functionality already here (you can just mount TcpSource() avs file), but it is with ugly code (i was read that somewhere) and without lagarith compression.

[joe48]

Originally Posted by joe48

If you can get me a sample exhibiting the problem I can look at it. Send me a PM.

The bug Zarxrax found is a divide-by-zero with clips that are less than 1 second long. I will have the fix in the next release.

[joe48]

Originally Posted by Quark.Fusion

What about adding multithreaded Lagarith compression for networking to AVFS? For user this can look like adding two variables to avs file with port number and compression method (like in TcpServer), on other side user will mount special file, that will

TcpSource and AVFS should interoperate fine.

I am not very familiar with TcpSource. It should not be necessary to know the compressed size of each frame in advance, so lossless compression could be implemented...

[tally3]

TGA sequences would be really useful!
http://www.organicbit.com/closecombat/formats/tga.html

[thommyfilm]

hello! sounds like very good work. one (maybe dumb) question: you say you would add output file format options. would it be possible to show an mpeg4 h264 file on the filesystem instead of a avi file? this should happen without reencoding. the input files are already mp4 h264 files.

[krieger2005]

You can't do it without reencoding. Every change, which you made with an avisynth-script to your video must be reencoded. This is a simple Law:
-> No change -> No Reencoding -> You don't need to use avisynth
-> change (in anyway) -> need reencoding

[mikeytown2]

@thommyfilm, thats what MeGUI is for

[Adub]

Uh, guys, I think he is asking if support for a "fake" mp4 front could be added in addition to the "fake" avi front. I don't know why this could be, as everything supports avi, while mp4 is much more limited.

[IanB]

Also would programs that accept MP4 containers handle uncompressed video and audio data. I suspect not.

[joe48]

There may be some performance changes when AVFS is used with the latest PFM Audit Package (build 048). I changed the caching in the file system driver to use 256k blocks instead of 48k. I did not test this against AVFS, probably should have...

I have some optimizations in the works for Pismo File Mount that will improve AVFS performance. Mainly there will be buffering improvements to eliminate extra data copying. It will be a while before I get this out, probably January.

Joe L.

[Adub]

Great!! I look forward to the next release!

Thanks for your hard work joe48.