Advice needed on best conversion to MPEG-2

[am_dew]

I have some video clips I downloaded that all look similar in MediaInfo as pasted below. Despite the low bit rate, the quality is not as bad as you may think -- see screen shot below the MediaInfo data. My question is about what bit rate I should use to avoid losing video quality when converting these files to MPEG2 format for eventual burn to DVD? I find it hard to believe that I could get away with using 2000 kbps and not lose quality, but then again I could be wrong. Opinions?

General
Complete name : K:\Clip1.f4v
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 138 MiB
Duration : 13mn 47s
Overall bit rate mode : Variable
Overall bit rate : 1 400 Kbps
Encoded date : UTC 2012-01-20 20:28:56
Tagged date : UTC 2012-01-20 20:28:56
Writing library : Apple QuickTime

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 13mn 47s
Bit rate mode : Variable
Bit rate : 1 144 Kbps
Maximum bit rate : 1 200 Kbps
Width : 854 pixels
Height : 480 pixels
Display aspect ratio : 16:9
Original display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 fps
Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.093
Stream size : 113 MiB (82%)
Language : English
Encoded date : UTC 2012-01-20 20:28:56
Tagged date : UTC 2012-01-20 20:28:56
Material_Duration : 827961
Material_StreamSize : 124595546
Material_FrameCount : 24814

[aedipuss]

use whatever bitrate fills the dvd. use a bitrate calculator. as long as it doesn't exceed the total allowable for the dvd spec when audio and other streams are added up.

[jagabo]

You can't convert to MPEG 2 without losing some quality. How much bitrate you need to maintain "reasonable" quality depends on many factors including the properties of the video (motion, noise, etc.) and your personal tolerance for artifacts.

You can't fill a DVD with 13 minutes of video. The highest bitrate allowed for video on DVD is 9800 kbps.

[_Al_]

My guess , below 5000 you will start to see some artifacts. Remember video gets new size, 720x480 with 16:9 flag.

As you perhaps know it is all about run time and how are you going to watch it. 8000 + audio is 1 hour and 15min or so......

You can be happy Peppy with 4000 on CRT but you'll will notice artefacts even with 6000 and higher on HD screen.

[am_dew]

You can't fill a DVD with 13 minutes of video. The highest bitrate allowed for video on DVD is 9800 kbps.

Understood. I have almost 90 minutes of clips just like the one I posted.

[jagabo]

You can't fill a DVD with 13 minutes of video. The highest bitrate allowed for video on DVD is 9800 kbps.

Understood. I have almost 90 minutes of clips just like the one I posted.

Then you're looking at the 6000 kbps range to fill a disk. That will probably be sufficient using a variable bitrate encoding -- given the source AVC video looks ok at 1144 kbps (ie, it probably doesn't have too much noise and motion).

If you really want the absolute best quality use 2 DVDs and 9800 kbps or less, depending on your audio requirements and any headroom you want to leave for poor players. Or use a dual layer disc.

[am_dew]

Thanks everyone. I guess my general question still remains and that centers around whether or not these specific clips will visibly degrade in quality if I choose, for example, a 2-pass 6000 kbps VBR, which I am pretty sure is the upper limit of what will fit on a single layer DVD with decent quality audio. Or do I need to go higher to be safe? I ask because of the low bit rates I see in the MediaInfo data. In other words, am I worrying about nothing since bit rates on the original clips is low?

EDIT: Thanks jagabo...your reply came in after I posted the above.

[jagabo]

Thanks everyone. I guess my general question still remains and that centers around whether or not these specific clips will visibly degrade in quality if I choose, for example, a 2-pass 6000 kbps VBR, which I am pretty sure is the upper limit of what will fit on a single layer DVD with decent quality audio. Or do I need to go higher to be safe?

There's no way to answer that. Every video requires a different bitrate in order to maintain quality. You're not going to know until you encode your video and look at it.

Look at the videos in this post:

https://forum.videohelp.com/threads/295672-A-problem-for-video-experts?p=1811057&viewfu...=1#post1811057

One of the videos required 20 times more bitrate than the other. Those are with MPEG 4 ASP but the issues are the same.

[davexnet]

The simple answer is to encode up a few and see if you can tell the difference. You might notice it, the
next question for you to answer is whether the difference is acceptable. 2-pass VBR @ 6000kbps
might be OK. Give a try.


The bitrate of the source is not really a factor, it's being uncompressed and recompressed (re-encoded) to a different
type (mpeg-2)

[am_dew]

The simple answer is to encode up a few and see if you can the difference. You might notice it, the next question for you to answer is whether the difference is acceptable. 2-pass VBR @ 6000kbps might be OK. Give a try.

OK -- will give that a try.

The bitrate of the source is not really a factor, it's being uncompressed and recompressed (re-encoded) to a different type (mpeg-2)

This was my suspicion...comparing apples to oranges -- good to have it confirmed.

Thanks again to everyone for your input...much appreciated!

[jagabo]

The bitrate of the source is not really a factor, it's being uncompressed and recompressed (re-encoded) to a different type (mpeg-2)

This was my suspicion...comparing apples to oranges -- good to have it confirmed.

It's not a 100 percent reliable indicator. But it can give you a hint. Especially since both are MPEG family codecs in this case. In all likelihood 6000 kbps VBR will be sufficient for you in this case, especially since you will be reducing the frame size to 720x480.