Quantcast Help Getting High Quality with TV Captures from Replaytv? - digitalFAQ.com Forums [Archives]
  #1  
05-29-2003, 02:25 PM
Grantman Grantman is offline
Free Member
 
Join Date: Sep 2002
Location: Northfield, IL
Posts: 102
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to Grantman Send a message via AIM to Grantman Send a message via MSN to Grantman Send a message via Yahoo to Grantman
I am having a very difficult time getting good quality output from original MPEG2 files off my ReplayTV. The resolution is 720x480 to start. They are decent quality when played on the PC or via ReplayTV.

Size is not a huge issue. Most of the files are 30 minute TV shows that end up around 21 minutes after commercials are cut.

My test example has been an episode of "Good Eats" from FoodTV. I have tried the current KVCD template, the 352x480 and the 352x240. Additionally I have tried 480x480 using the KVCD as the starting point.

With each template I have tried both reference scripts posted under "Optimal Scripts" as well as the script posted in the "Mini Guide" above. (The only addition to the scripts I used is to add FieldDeinterlace(). I have also tested each with TomsMoComp (0,5,1)

Each test file is burnt using Nero as a VCD. All the files I have created play fine. However, the quality seems very poor. There is noticable noise or blocks around objects. Also, the picture always seems slightly blured or soft.

After these several tests did not produce well I tried a couple of rounds adding and subtracting filters and could not do much for the noise or blocks. I kicked up the CQ +5 in each template and it helped a little but not enough. (Shouldn't the CQ in the templates be more than enough for TV? It is not high action stuff.)

Each test file is put on a CD-R. I have a pile of 30 failed tests.

Do I have an unreasonable expectation of quality or is there some trick to getting the same quality from these files as I get when doing movies from DVD. I get good results when taking an existing DivX movie and encoding with KVCD. Results are decent when the ReplayTV capture is from DVD or VHS source.

The only problems I have are with broadcast signal sources. I am getting the signal from analog cable (no box). It looks clean on the TV and the file appears clean when played on the PC after being copied off ReplayTV. (The file are very big though. Around 1.25GB per 30 minutes).

Any help would be appreciated. I am hoping there is a secret filter for broadcast TV that solves this problem. (PeachSmoother did not do it!)

Grantman
Reply With Quote
Someday, 12:01 PM
admin's Avatar
Site Staff / Ad Manager
 
Join Date: Dec 2002
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #2  
05-29-2003, 04:03 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Hi Grantman,

First of all, what file format are the captures recorded in?
I mean, is it standard MPEG-2 video stream and .mp2 audio, or is it AC3 audio?
Just want to know, because there might be something else muxed in there, and that's what's causing your quality problems
btw: How do you get the file to your PC from the ReplayTV?

-kwag
Reply With Quote
  #3  
05-29-2003, 04:39 PM
Grantman Grantman is offline
Free Member
 
Join Date: Sep 2002
Location: Northfield, IL
Posts: 102
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to Grantman Send a message via AIM to Grantman Send a message via MSN to Grantman Send a message via Yahoo to Grantman
The files are MPEG2 files. They come off the ReplayTV via software on the PC. It is a java application that copies a single MPEG2 file.

I use DVD2AVI to create a project file and an audio file. I then use MovieStacker to create the initial script. (I edit that script to make it match the reference script I choose).

When I encode I specify the script file and the audio file in TMPGEnc. I then apply the correct template and change it to encode both video and audio (and switch the framerate to 29.97).

The files will play on the PC but not regularly. (Yes... the same file will play one time and not play another time).

From reading other posts in on other sites it appears the ReplayTV files are true MPEG2 files with a slight modification to the header information that is unique and specific to the ReplayTV internal software.

Grantman

P.S. I have since bumped the CQ even higher (70) and it does clear up many of the artifacts but the file is huge and still looks a bit blurry and soft.
Reply With Quote
  #4  
05-29-2003, 04:44 PM
Grantman Grantman is offline
Free Member
 
Join Date: Sep 2002
Location: Northfield, IL
Posts: 102
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to Grantman Send a message via AIM to Grantman Send a message via MSN to Grantman Send a message via Yahoo to Grantman
I opened one of the MPEG2 files in MPEG Properties and it reports the following:

720x480
29.97 fps
VBV buffer size=12320
Video bitrate=9800 Mbit/s or 1196 kByte/s

# stream id's in header=60
Audio_bound=32
Video_bound=1

I also get several errors from the program about an invalid audio header. The error is only with this program not when using VirtualDub or DVD2AVI.


Grantman
Reply With Quote
  #5  
05-29-2003, 05:33 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Hi Grantman,

Open your MPEG file with TMPEG tools selecting the "Demux" option.
See how the streams are identified, and how many are there?

-kwag
Reply With Quote
  #6  
05-29-2003, 07:07 PM
Grantman Grantman is offline
Free Member
 
Join Date: Sep 2002
Location: Northfield, IL
Posts: 102
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to Grantman Send a message via AIM to Grantman Send a message via MSN to Grantman Send a message via Yahoo to Grantman
There are two streams listed:

video_stream 0x00

audio_stream 0x00 (MPEG-1 Audio Layer-2 48000Hz 192kbps)


Grantman
Reply With Quote
  #7  
05-29-2003, 07:45 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Grantman
There are two streams listed:

video_stream 0x00
If you open that stream wth VirtualDub-MPEG-2 version, does it look clean, or are there some artifacts? You must download Vdub MPEG-2, not the regular Vdub version
Get it here: http://es.geocities.com/dextstuff/
Reply With Quote
  #8  
05-29-2003, 09:02 PM
Grantman Grantman is offline
Free Member
 
Join Date: Sep 2002
Location: Northfield, IL
Posts: 102
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to Grantman Send a message via AIM to Grantman Send a message via MSN to Grantman Send a message via Yahoo to Grantman
Interesting...

If you compare any 1 given frame it looks much cleaner in any of the sample MPEG1 files I created than it does in the source. The source is grainy with broadcast TV artifacts visible in the background and on stationary areas. It looks like a very light fuzz type noise.

However, when played by the ReplayTV it looks very clean and sharp. When the sample files are played they look TOO smooth and there are artifacts around peoples heads. arms, fingers and another other moving details.

Again, the fuzz/noise is cleaned up but the overall video is way to soft. It is almost like a blur. This is even in the absence of any extra filters.

Two things are occuring to me...

1) The ReplayTV is very optimized to play it's own files. So much so that it compensates for what is a noisy source.

2) Something about the amount of noise and the capture of the MPEG2 on the ReplayTV is fooling the filters and TMPGEnc into over smoothing the entire video and creating artifacts or noise blocks around the edges of slow moving objects. (A higher CQ does help but I should not have to go up to 70 or 75 to eliminate these artifacts).

Maybe a better tweaked set of filters or newer filters will help enough to keep the file sizes in check. I would like to get at least 45-60 minutes on a 700MB CD.


Grantman
Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
DVD2SVCD: High quality audio settings? warezfreak Video Encoding and Conversion 6 07-17-2004 02:43 PM
DVD2SVCD: Motion search or high quality? ftin Video Encoding and Conversion 2 05-26-2003 10:48 AM
KVCD: Limit to how high CQ will benefit quality? heller Video Encoding and Conversion 2 02-19-2003 10:01 PM
DVD2SVCD: D2S High Quality Yoda Video Encoding and Conversion 1 10-29-2002 06:46 PM
trying to get my DV Cam movie on VCD at high quality cardoso Video Encoding and Conversion 8 07-27-2002 07:31 AM

Thread Tools



 
All times are GMT -5. The time now is 05:02 AM  —  vBulletin Jelsoft Enterprises Ltd