Maintaining aspect ratio with ffmpeg transcoding

[zehd]

Gotta couple of questions...

If I end up creating an mpeg that's 720x480 then the MVP should play it without aspect ratio adjustment?

I thought I read somewhere that you could throw other 4x3 ratio files at the media mvp, without too much trouble... so 360x240 should work...

But when I choose ffmpeg to use 360x240 it auto adjusts it to 368x240

I don't understand...

[zehd]

So close I can almost smell it.

OK The tip on requiring more processor was a good one. I played with bitrates and realized that 1000 looked pretty good and was much faster than 4000.

And then, I was able to start an AVI. It started the Trans2MVP.bat and then there was a half a screen of video. Then I stopped it. Magically there was the same filename, but with an MPG extension (that's in my batch file). The batch file was still in the middle of the transcode, but I could click on the mpg in progress and WOW, I had the video playing, centered, wide screen and smooth.

I was able to do it over and over again. I would start the avi, it would be squished, stopped it, and then started the MPG in progress. Worked perfectly.

Then something weird happened. Now I select the avi, it crashes the MVP server app, the mvp resets... Meanwhile, the Trans2MVP is running merrily away.

When the MVP finally locks in, I can start the MPG and it's perfect again.

My question is, what happened. I would be happy to start, stop and start the MPG. it would be a fine, quick and dirty workaround. But now there's a couple of minute downtime as the mvp locks in again.

Is there something in the logs?

[ATTACHMENT NOT FOUND]

[sub]

From the logs.

08/06/2006 9:24:28 AM.093 ERROR [10] Media stream thread caught exception: Could not find file 'C:\TV\Recorded\MVP000DFE08D22E.mpg'.
08/06/2006 9:24:28 AM.343 ERROR [10] at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
at GBPVR.xbb1566157f5f8b1f.xf9d81bb81f7c2ff0()

[drain]

I was really thinking that a 2.0ghz machine should be ok..

My Celeron 2.66 transcodes to 720x576 with CPU to spare.

PS. I'm thinking of a way to kill the previous MPG file. My idea to kill the previously created MPG files is: In the Trans2MVP, store the output filename to an external text file...

I've lost track of where things are up to, but have you tried running ffmpeg directly instead of using the "start" command? I seem to recall when I tried it this way gbpvr was able to kill the task when I pressed stop on the remote. Perhaps there is another way to set the task priority without creating a new process (as I think "start" does).

[zehd]

Media stream thread caught exception: Could not find file 'C:\TV\Recorded\MVP000DFE08D22E.mpg'.

I noticed this file being created when GB-PVR calls ffmpeg directly.

Am I correct that if I use Trans2MVP.bat, then I must also set the Output file path to be based on the MVPs Mac address and located in the recording directory?

I originally thought that GB-PVR will use whatever output file that is created from Trans2MVP.bat

That would certainly be easy - for one MVP Mac address. Hard code the mac into the batch file.

But what if a person has two... If GBPVR would send a parameter to the Trans2MVP that would say which Mac is calling the batch...

[zehd]

My Celeron 2.66 transcodes to 720x576 with CPU to spare.


I've lost track of where things are up to, but have you tried running ffmpeg directly instead of using the "start" command? I seem to recall when I tried it this way gbpvr was able to kill the task when I pressed stop on the remote. Perhaps there is another way to set the task priority without creating a new process (as I think "start" does).

No kidding, lost track...

Anyway, seems a few of us have been bastardizing your batch file.... I'm just finalizing something that is starting to work great...

[zehd]

I noticed sub saying he's going on holiday. (well deserved) and we should fend for ourselves...

I I got to thinking that maybe already passes two veriables to Trans2MVP.bat.

%1 a file to be transcoded
%2 the filespec for the output file, it is expecting to actually display.

Can anyone confirm this?

Can someone add an: echo %2 in Trans2MVP.bat and tell me what it says...?

[cakes]

%1 a file to be transcoded
%2 the filespec for the output file, it is expecting to actually display.
Can someone add an: echo %2 in Trans2MVP.bat and tell me what it says...?

correct, these are just the parameters that GBPVR uses to call trans2mvp.bat. In the logfile I added to my trans2mvp.bat, I get this from echo %2:
"J:\TV\REC\MVP000DFE0072EC.mpg"

[cakes]

actually, the most basic trans2mvp.bat you could make is just 1 line:

Code:

C:\Progra~1\devnz\gbpvr\Thirdp~1\FFmpeg\ffmpeg.exe -y -i %1 -b 2400 -ac 2 -ab 224 -s 352x288 -f svcd  %2

[zehd]

correct, these are just the parameters that GBPVR uses to call trans2mvp.bat. In the logfile I added to my trans2mvp.bat, I get this from echo %2:
"J:\TV\REC\MVP000DFE0072EC.mpg"

Thanks Cakes...