Advice: ComSKip and Transcoding on Second PC?

[nurowolf]

Would this be possible at all? If so, can somebody point me in the right direction to get started.

The Plan:
------------
To have a scondary PC in the study do all the transcoding / commercial removal work - thereby leaving my HTPC (with GBPVR) running unhindered and always available.

So what I would like to do is do the recordings on the Server, then upon completing the recording, pass the next processing responsibilities over to a secondary server. I figured I may be able to use PostProcessing.Bat to achieve this.

My initial plan was to use Girder with GBPVR. SO have PostProcessing.Bat issue a girder event that activates the Other Server Machine.

However PostProcessing.Bat will then complete and I can't see a way to update GBPVR with the new file name.

Any other ideas?

[zehd]

Would this be possible at all? If so, can somebody point me in the right direction to get started.

The Plan:
------------
To have a scondary PC in the study do all the transcoding / commercial removal work - thereby leaving my HTPC (with GBPVR) running unhindered and always available.

So what I would like to do is do the recordings on the Server, then upon completing the recording, pass the next processing responsibilities over to a secondary server. I figured I may be able to use PostProcessing.Bat to achieve this.

My initial plan was to use Girder with GBPVR. SO have PostProcessing.Bat issue a girder event that activates the Other Server Machine.

However PostProcessing.Bat will then complete and I can't see a way to update GBPVR with the new file name.

Any other ideas?

I think running a process on a remote file with something like comksip would be difficult.

But what you might want is to use dirmon on the transcoding computer. It would monitor the Recordings computer and when the file is finished, it would start transcoding and comskipping.

I have thought that I might have a separate computer run an antivirus check on my PVR computer just so that I don't have to have and AV on the PVR at all...

Never did it though...

Maybe what a compromise is having comskip run during the recording, and then have your remote computer transcode the files, then you won't really have a time problem...

[pastro]

The trouble is you still will have the disk accesses and network accesses on the HTPC machine. That's going to make things pretty slow too, won't it?

[zehd]

The trouble is you still will have the disk accesses and network accesses on the HTPC machine. That's going to make things pretty slow too, won't it?

Of course, depending on speed of disks, but I think the real overhead is the CPU on the processes...

[pastro]

Of course, depending on speed of disks, but I think the real overhead is the CPU on the processes...

That's what I thought too, but Erik (comskip) made a comment that said the performance hit is usually from all the disk accesses since comskip runs at idle priority.

My Laptop goes to crap, if someone is downloading a large file over the network from me. Seems like that would be the same deal.

[erik]

The real question is how many recordings you do in paralel and if you record SD or HD.

On AMD Geode 1400MHz you can do two recordings in paralell and at the same time run comskip on both ongoing recordings without noticing the CPU or disk load.
When run comskip after the recording comskip will load your CPU to 100% and exercise your disks. The CPU load is not a problem because it run's at idle priority so any other activity will have priority. The real problem becomes the disk load and the memory usage. Other programs will run slower because of the disk and memory load, not because of the CPU load.

You can also ask comskip to run in play_nice mode where it will slow down processing. This will reduce the disk en memory load and you won't notice much of comskip.

Things change when you record HD or with many tuners because most CPU's then won't be able to keep up with the recording and the comskip processing time becomes larger then the paralel recording time.

Running comskip from a separate computer accessing the recordings over the network will slow down comskip and give the network a high load.

But do remember that any transcoding does take much more CPU time then comskip.

[nurowolf]

I was looking at off-loading the entire process to a second CPU (system).

I currently run a Gigabit network throughout the home. The PC is only recording SD (I am in HK - they aren't delivering HD content yet).

The hard disks will be a NAS with a Gig connection.

The real issue I thought would be telling GBPVR that the file has changed from

--> Filename.mpg

to

--> Filename.avi

after the transcoding has been completed.

The secondary machine will just perform the transcoding and comskip duties and nothing else.

[erik]

On SD 5MBit/s recording comskip runs at about 400fps on my 1.6GHz laptop that is about 15 times realtime. On a more modern and faster CPU you should be able to get at least 20 times realtime. That will load a network at 100MBit/s. No problem for a GBit network.
When doing comskip and transcoding you will read the mpeg twice.
A typical modern disk can do 50MByte/s or 500MBit/s so you could consider to first copy the mpeg to a local disk. Then you run comskip and then the transcoding. Depending the network/disk speed ratio you should start comskip at the start of the copying or wait till the copy is finished (because of the extra seeking during simultanious reading (comskip) and writing(copy).
However it even may be better to run comskip on the recording machine. When you run comskip in paralell to the recording on a CPU faster the 1500MHz with 2 or 3 tuners you will hardly notice it.

[gEd]

The real issue I thought would be telling GBPVR that the file has changed from

--> Filename.mpg

to

--> Filename.avi

after the transcoding has been completed.

Actually that isn't a problem. If gbpvr cannot find the mpg file, it will look for an avi file instead. However on startup, if gbpvr cannot find the mpg or avi, it will be deleted from the database. [edit] this behaviour is controlled by <AutoRemoveMissingRecordings>false</AutoRemoveMissingRecordings> in config.xml.

[edit] with gigabit and NAS disks you can probably just run dirmon from the transcoding pc to copy the files to a local disk, transcode and then copy avi back to original folder and delete mpg. This could screw up if you happened to be watching the mpg at the time.

[rscheller]

... However it even may be better to run comskip on the recording machine. When you run comskip in paralell to the recording on a CPU faster the 1500MHz with 2 or 3 tuners you will hardly notice it.

erik, there's two instances in this thread where you've suggested that, if one has the CPU power, it's much better to run comskip concurrently with the recording process rather than after the recording has finished.

Am I reading that correctly?

Thank you for authoring comskip... it's truly changed my TV viewing habits as I rarely watch anything live anymore because of the commercials.