Help needed with GOP settings

[Dave Friend]

Kenny,

I assume you are going to use the Adobe Media Encoder. If so, setting M=1 and N=1 should give you an I frame only file.

Make sure to choose the MPEG2 format in Adobe Media Encoder and not the MPEG2-DVD format.

Ask them to specify the bitrate and if they want CBR or VBR.

You should probably ask the client what Profile and Level too.

Some broadcast servers are very particular about these items.

Dave

[Kenny Frankland]

Thanks for the reply Dave.

you assumed right, I am using adobe media exporter. I’m having a huge headache with this.

Here are the specs the broadcaster have given me:

Broadcast Quality
Video Format: MPEG-2 422P@ML 4:2:2
Video Bitrate: 50 mbps I Frame Only
Resolution: 720×608 (we can accept 720×576)
Frame Rate: 25
Rate Control: CBR
Audio Channels: 2Ch Stereo pair
Audio Bitrate: Mpeg 1 layer 2
Audio Bit Rate: 384 kbps
Audio Sample Rate: 48 kHz
Filed dominance: 1st field / Upper field first.

I’ve done everything the specs require and I get a horrible blocky movie the moment I export using a 4:2:2 profile.

my premiere export settings are:

Format: MPEG2
Codec: Mainconcept MPEG
Quality: 5
TV Standard: PAL
Width : 720
Height : 576
Frame rate : 25
Field Order : upper
Aspect ratio : Widescreen 16:9 (1.422)
Profile : 4:2:2
Level : Main
Bitrate Encoding : CBR
Bitrate : 50 Mbps

M Frames : 1
N Frames : 1

Closed GOP : 0
Auto Gop Placement (unchecked)

I haven’t touched the Advance settings so they should be at default.

Any ideas?

Thanks in advance.

[Dave Friend]

Kenny,

I tried experimenting with the 422 profile and cannot make a usable file either. All settings variations I had time to try produced the same blocky output. My conclusion is that AME cannot do it.

I have a copy of Procoder 2 that created a good looking file from an avi input. There is a 422P profile available but it will not allow a bitrate of 50Mbps at the Main Level. It will if at High Level. Maybe the newer version of Procoder is different and allows higher bitrates with 422P:ML.

Seems that you might have to find a different encoding solution for this one. I’ll be curious to hear about your solution.

Dave

[Kenny Frankland]

Hey Dave

Thanks for your efforts. I have found a solution and it’s kinda strange.

I asked an old colleague of mine if he had any ideas and after I gave him the specs I was working too, he responded with a message that his test movie came out fine first time. So I went round to his with my uncompressed original (my source is rendered animation) and he converted it with no problems using AME, but in Prem Pro 1.5. I have been using CS3. The settings where exactly the same as what I was trying in CS3 so this leads me to believe it may be a bug of some kind?

I’m going to try my old 1.5 on my machine and try exporting again.

I’ll let you know my results…

[Bernardo Garcez]

I know it’s toooooo late!
But I had the same problem and if someone also go trough this, I want to tell my experience.
I was asked to export a video to be used in a big screen, in a soccer stadium.

The specifications they told me were:
– Video format: MPEG2 TS (Transport Stream);
– Max Resolution: 1920×1080;
– Bitrate: 15 Mbps and Bitrate Enconding CBR (Constant Bit Rate).
– Audio format: MPEG;
– Audio Layer MPEG-1 or Layer 2;
– Stereo.

I exported exactly what they wanted and, trying to have more quality, I changed de GOP settings to: M-1 and N-1.

The video was blocky to. It looked like the pixels were 8 times bigger.
Than, I tryed to leave the GOP settings as default (3 and 15). Now I have a video without those blocs. It’s not that very beautifull quality, it’s looking like some grain in the image, but so much better!

The prints:

7833_01.jpg.zip

7834_02.jpg.zip