PDA

View Full Version : Dummies guide converting "DVB-mpeg-recording to divx"


kevingpo
1st March 2006, 20:42
I was happily living on free trial of VideoReDo & MPEG Video Wizard DVD (to convert my DVB-mpeg2-recordings to divx) until they both expired. I could easily get another trail key, however I decided to follow the doom9.org DVB-2-divx guide ( http://www.doom9.org/DigiTV/dvb2divx.htm ) using freeware.

----Steps 1 - 4: Recording, Demuxing and Cutting----
If DVB-mpeg2-recording contains resolution changes during breaks/adverts then this results in GOP/PTS errors.

I use ProjectX default settings to demux my mpeg2 file to m2v & mp2 files.

I use MPEG2Schnitt (cool German program) to cut my m2v video file. Resulting file is one mpv file. I guess I shouldn't delete my mp2 audio file.

----Step 5: Create a DGIndex project----
I load up DGIndex and open the mpv file. I find out my recordings have been in PAL, 4:3, 25fps. I press F4 (save project). Finished file is a d2v file.

----Step 6: Gordian Knot----
I forget to rename my mp2 audio file to mpa (as stated in the guide) but I still continue.
I chose DivX5 because it's the best and most familar. Load up Gordian Knot. Open d2v file. Check PAL, AVI, DivX5, 4:3, 25fps, Smart Crop All are selected.


PROBLEM 1: Why hasn't my sound/audio been automatically loaded/set up? So I click open in audio1 box. However it doesn't see my mp2 file. But I force to load it via Show All Files.


Hmm, next section is sliding the resolution slider? Scary I do not know what to do so I leave it as default.


PROBLEM 2: My Bits/(Pixel*Frame) values are lighting up yellow 0.111. I do not know what is going on?!


In the preview window I select "Save & Encode". A massive encoding settings window popup. I leave everything default.


PROBLEM 3: Audio 1 tab, "Just Mux" or "Audio-processing disabled"? Which one? Wasn't my audio processed already?

kevingpo
1st March 2006, 21:51
Okay, I gave up on Gordian Knot - even though it's the best to customise and tweak the encoding, it's hard to use and takes 10x longer than automated programs likes Dr. Divx or AutoGK.

After cutting with Mpeg2Schnitt, I multiplex them back together again using the Simple Multiplex tool in DMPGEnc. Then we have a very good mpeg2 video/audio file... which we can feed through Dr. DivX (if we want DivX6), or AutoGK (if we want DivX5 or Xvid).

jwexqm
8th May 2006, 17:10
Here my DVB reception isn't perfect so I occasionally get bitstream corruption which is of course also contained in the recordings I make. If I play these MPEG2 files in any media player (ZoomPlayer, MPC), playback glitches as expected but the AV sync is preserved after the corrupted section passes.

Recently I tried to encode a recording that I'd made from MPEG2 to XviD using AutoGK. As ususal, the recording contained a few glitches. AutoGK processed the file and encoded an output AVI fine, however after every glitch the audio became further and further out of sync (audio was late).

The reason for this (I believe) is the way that the audio and video are treated when they are demultiplexed during the encoding process. I reckon that the video drops frames (thus compressing time) during corruption but the audio continues in real time with pops and squeaks. Over the duration of the recording the audio then becomes later and later with respect to the video.

I presume that when the audio and video are multiplexed together in the MPEG program stream, they are both anchored in time, so resynchronisation automatically happens. This would explain why the MPEG2 recording plays with no AV sync issues in a media player.

Does anyone know of any pre-cleaner that can fix these errors in an MPEG2 program stream so that when the A & V are demuxed, they both still "line up" in time?

Cheers,
James

Vanderlow
8th May 2006, 21:05
I hope I'm not off topic, but here's a thread that tells how to easily make a DVB mpeg stream DVD compliant so it will play in any standalone DVD player.

http://forums.al7bar.tk/showthread.php?t=19366

BigDid
8th May 2006, 22:39
...Does anyone know of any pre-cleaner that can fix these errors in an MPEG2 program stream so that when the A & V are demuxed, they both still "line up" in time?...
Hi,

PVAInstrumento or mpg2cut2 alone (for cutting and synching);
using mpg2cut2 I have only the delay within my Sat capture: 15 to 20ms to deal with :)

Did

kevingpo
9th May 2006, 09:17
Hi,

PVAInstrumento or mpg2cut2 alone (for cutting and synching);
using mpg2cut2 I have only the delay within my Sat capture: 15 to 20ms to deal with :)

Did

I have yet to get fully acquinted with PVAInstrumento, but I got used to ProjectX. When you say Mpg2cut2, do you mean that German program Mpeg2Schnitt?

kevingpo
9th May 2006, 09:19
I hope I'm not off topic, but here's a thread that tells how to easily make a DVB mpeg stream DVD compliant so it will play in any standalone DVD player.

http://forums.al7bar.tk/showthread.php?t=19366

Yes, that article uses TMPGEnc's DVD Author which is a fantasic product!

BigDid
9th May 2006, 10:32
I have yet to get fully acquinted with PVAInstrumento, but I got used to ProjectX. When you say Mpg2cut2, do you mean that German program Mpeg2Schnitt?
No,

Really mpg2cut2 from Jackei? at Rocketjet (http://www.geocities.com/rocketjet4/)

Did

jwexqm
9th May 2006, 12:30
I've now tried ProjectX, PVAStrumento, Womble and mpg2cut2 but I'm still not able to demux this stream in sync. Thanks to all for the suggestions of tools to try.
I've cut out a 16mb section that shows up the problem well. There's a scene of lip-synced speech at the beginning, some corruption in the middle and another scene of lip-synced speech at the end. It plays in sync in VLC, MPC etc. but once demuxed the audio is always longer than the video. I have a feeling I may have missed a critical setting on one of these tools that will sort this out.

Anyway here's the sample clip (http://rapidshare.de/files/20009085/test_clip.zip.html) (rapidshare I'm afraid).

[edit]

Well, I've since thrown some more time at this and found that by going back to PVAStrumento with this shortened sample clip, it does in fact demux in sync. My initial failure using PVAStrumento may have been because the whole recording file is so long (2hrs). Anyway I'm now cutting the recording into successively longer and longer segments and repeating the PVAStrumento demux to see if it falls over at any particular point.
My methodology for testing the demuxed streams is as follows: demux the mpeg2 file into an m2v and mpa and then lay them both down into Womble on the time-line. It's immediately visually obvious if both files are not the same length. You can then seek to any arbitrary position and test for lip sync by playing from the cursor position.
I'm really looking for a flow that works consistently for me.
My recordings start life in dvr-ms format from a Windows MCE machine. I'm then converting them to mpeg2 using the .net command line tool 'dvrmstoolbox' with the following command line...

DVRMStoMPEG.exe /if="in.dvr-ms" /of="out.mpeg" /act=dvrmstompg

Then I trim the resulting mpeg file and remove commercials with Womble. Now it's looking like the next step will be to clean the output from Womble with a pass through PVAStrumento. Hopefully I'll be able to use it to clean straight to an mpeg2 program stream so I don't need to go through a demultiplex and re-multiplex. Finally I hope that what comes out of PVAStrumento will go straight into AutoGK and result in a nice, synced XviD encoding.