How to set Bitrates and Datarates for MPEG2’s

[Aryn Leigh]

This is fairly straightforward.

I am trying to export an MPEG2 (I’m downgrading a 1080p timeline to SD.)

The client is requesting the following settings, but I don’t know exactly how to input these within the parameters that I’m given in Premiere’s MPEG2 export settings.

They are requesting the following:

Resolution: 720×480
Frame Rate: 29.97
Datarate: 8000 kb/s
Audio
Channels: Stereo
Sample rate: 48000 Hz
Bitrate: 224 kb/s

First, how exactly do I set the correct data rate and bitrate?

Lastly, in the settings, do I choose “square pixels” or “standard 4×3”? There seems to be a slight stretch when I choose “Square Pixels”.

Thanks in advance.

[Aryn Leigh]

Thanks- emailing her now to get details.

I should mention, they also want a 720 version with the following specs:

HD – MPEG 2 (Transport Stream)
Resolution: 1280×720
Frame Rate: 29.97P
Datarate: 20000 kb/s
Audio
Channels: Stereo
Sample Rate: 48000 Hz
Bitrate: 224 kb/s

… I have basically the same options for export here.

Assuming then that this is not for DVD, do you know how to achieve these specifications out of Premiere?

Thank you again-

AL

[Todd Perchert]

When you go to the MPEG2 format in your export settings, you’ll have some Presets. For DVD, select NTSC DV Wide. Or NTSC DV. Wide will give you a slight black border on the sides. NTSC DV will give you black letterbox on the top and bottom. Either way you can scroll down to the Video Bitrate settings (Datarate) and change from VBR to CBR, then put in 8 Mbps, which will be your 8000 kbps.

For your 720 mpeg2, do the same MPEG2 format selection. But use the Preset HD 720p 29.97. Scroll down to your Video Bitrate again and change it to 20Mbps.

For both you can go to the Audio Settings tab and change the Bitrate for the audio if you need to.

Hope this helps!
TC

[Aryn Leigh]

Thank you all, this is most helpful!

… But now she is asking for a Datarate at 8000 kb/s and a Bitrate of 224 kb/s.

What is the difference?

Thank you again…

[Jeff Pulera]

I’m fairly certain the client is requesting an MPEG-2 file for their video server, as a TV or cable station would use. This MPEG-2 file will use different parameters than MPEG-2 DVD format.

“Datarate at 8000 kb/s and a Bitrate of 224 kb/s”

8000 is the VIDEO data rate, with AUDIO being 224

As a starting point, I have selected MPEG-2 as the export Format, and chose the DG FastChannel 480 Preset, as that preset is for a playout server. This gets us in the ballpark, then a few tweaks need to be made.

The client needs to get you more specific information yet, such as:

• 4:3 or 16:9
• Progressive, Upper Field, or Lower Field
• MPEG or Dolby Audio

Under the VIDEO tab, I’ve changed 4:3 to 16:9, and Lower Field to Progressive, and video bitrate to 8. Just guessing on aspect ratio and fields though, check with client for their preference.

Under the AUDIO tab, MPEG audio was the default and I only changed bit rate to 224.

I’m sure this will be helpful to get you going, but definitely consult with client to get additional details as mentioned above.

Thanks

Jeff Pulera
Safe Harbor Computers

[Todd Perchert]

She is confusing terms, but you basically have 2 bitrates – one is your video bitrate (which she is calling datarate) and the other is your audio bitrate. Usually video bitrate will be in Mbps, not Kbps, but 8000 kb equates to 8 mb. If you lok at the pulldown in your exports settings for the Audio bitrate, you will get increments like 128, 160, 192, 224, 256 and so on….

Hope this helps!
TC

[Aryn Leigh]

This is so great.

So I’ve noticed that with the SD 16×9 Widescreen setting, there are slight pillarboxes on both sides. I can’t remember why this is the case with SD, but I did increase the size to 720×486, which cropped the top I’m sure slightly but eliminated the black bars. Is there a more technical workaround to getting rid of the black bars?

Thank you all so much!

[Todd Perchert]

In your Export Settings there is a dropdown upper right for Source Scaling. You can select Scale to Fill and it will crop the top and bottom to fill those little pillar boxes you are talking about.
TC

[Jeff Pulera]

Do what Todd said – you don’t want to change the 720×480 sizing

Thanks

Jeff Pulera
Safe Harbor Computers

[Aryn Leigh]

Great. Thank you for this!!