MPEG encoding

milesy wrote on 11/28/2007, 12:30 AM
Hi Guys
i own an SR7 Camera which as you know provides me with m2ts files which contain video and 5.1 sound.
My problem is that my computer is not fast enough to play the HD video properly so i basically need to render the video to a format that i can edit - either AVI or MPEG2.
When i do either of these i lose the 5.1 surround sound - the AVI provides me with a stereo track but the MPEG2 is video only.
So my question is - how to i render to either of the above and retain the 5.1 sound??

thanks in advance
Adrian

Comments

Eugenia wrote on 11/28/2007, 2:29 AM
You can't. You have to use another trick. You must create "proxy files", at a low resolution, e.g. 480x270, then edit as such, save your project, and then move these files elsewhere and replace them with the .m2ts files that happen to have the same file name. This way you edit in a low resolution setup that your PC can handle, but for the FINAL render you use the .m2ts files.
milesy wrote on 11/28/2007, 2:40 AM
interesting thought.....ill give this a shot, thanks for your advice
milesy wrote on 11/28/2007, 2:44 AM
OKQ this might sound like a silly question, but how can i reduce the resolution of the 'PROXY' file???
Eugenia wrote on 11/28/2007, 11:24 AM
The easiest way is to write a script that goes through a given folder, reads one by one all the video files captured, then using ffmpeg you re-encode these files with the same filename, on another folder, at a lower resolution. Then, you edit these lower resolution files. You save the project and quit vegas, you copy over the small files the big files, you load vegas again, and then render out.
milesy wrote on 11/28/2007, 1:52 PM
ok thanks again.

One more question. If i take the m2ts file from the SR7 (1440 x 1080) and use the MPEG2 format to render the file,(which is set to 720 * 576 widescreen) why does the resulting image use only a percentage of the available viewing screen.
That is the image is 'letterboxed' all the way around the image ?? am i missing something basic.
If i use the AVI setting to render the resulting image is as you would expect

Adrian
Eugenia wrote on 11/28/2007, 3:30 PM
Grab a screenshot so we can see the problem.
milesy wrote on 11/29/2007, 3:30 AM
sorry for the poor shot but you can clearly see in the preview window that the video is smaller than the output area.

As i said set to 720x576 but for some reason in rendering smaller when using mpeg2

http://adrianmiles.myphotoalbum.com/view_photo.php?set_albumName=album06&id=screenshot

just for you info (if it helps) the settings under the preview window read

Project 720 x 576x32, 25.0000i
Preview 360x288x32, 25.0000i
Frame 34
Display 524x288x32

Chienworks wrote on 11/29/2007, 4:35 AM
Looking at your screenshot, it really looks like the clip on the timeline is really a 4:3 file which contains letterboxed widescreen video. You can see the black bars across the top and bottom in the thumbnail. If it was really widescreen format then those black bars wouldn't be shown. Now you have your project properties and preview window set to widescreen, so Vegas fits the 4:3 image into the widescreen frame, adding black bars on the sides in order to make it fit. Since the media file contains black borders top and bottom and Vegas adds black borders on the sides you end up with the result you see ... a smaller image with black all around it.

Try this: open up Pan/Crop on the event on the timeline, right-mouse-button click inside the framing rectangle, and choose "Match output aspect". That will crop the image down to just the widescreen part eliminating the black borders on top and bottom. Vegas can then fit that cropped image inside the output frame much more accurately.

Now, that also brings up the other question ... if your original material is HDV 1440x1080 which is widescreen, how did you end up with a clip that is 4:3 letterboxed instead of 16:9? Assuming that the information at the bottom of the explorer window is correct it looks like you're using an SD MPEG file so that's not the original clip. Is that the proxy file you've created? I'm guessing it is, and that you rendered to a 4:3 file instead of rendering to a widescreen file.
milesy wrote on 11/29/2007, 12:26 PM
ok here is what i think is happening - see if this makes sense

it looks like if i choose file type as MPEG2 (mainconcept) and the template as DVD (pal) then it renders the file as Chienworks said to a 4:3 - the custom button is greyed out so there is nothing to change this.
If i use the DVD Architect for Widescreen template then it renders correctly, however this template has no sound.....

is there a way to change the DVD PAL template or is there another plug in to use for this

i really appreciate all your help here
Chienworks wrote on 11/29/2007, 1:54 PM
I don't have the studio version so i can't see the menu options available. Isn't there any other widescreen PAL choice besides the DVD Architect template?

How about WMV? Can you include 5.1 audio in any of those templates?
4eyes wrote on 11/30/2007, 4:56 AM
Start a new project.
Right Click on the preview window and make sure that:
Simulate Device Aspect Ratio = ON
Scale Video to fit preview window = ON
Preview = Auto

Here's how to make a dvd with your avchd using a proxy file & retaining the 5.1 audio.
File -> Properties Select HDV 1080i -50 (Rendering Quality Best) leave everything else default on this tab.
Audio Tab = 5.1, 48khz, Best Click OK & back to the WorkSpace.
Use the VMS Explorer, locate your m2ts file, drag it into the "Project Media" bin.
Then drag & drop it on the "Video Track". You should now see your 5.1 audio, front is a stereo track, Center should be a Mono track and Rear (surround) is a stereo track.
Save the project.
Create a proxy file:
File | Render As:
Save As Type = Video for Windows (*.avi) - Template = PAL DV Widescreen
Click on "Custom", goto the "Audio Tab" & uncheck include audio.
Save the file "Proxy_xyz"
Go through VMS explorer again and put the proxy file into the project.

Highlight your video track & hit th "U" (ungroup) key. With the video highlighted hit the delete key.
You should now see only your 5.1 audio tracks.
Drag your proxy file into the video track which now replaces the avchd video.
Goto "Edit - Select ALL ( Ctrl + A ), then hit the "G" (Group) key to group them.
You definitely need everything grouped for editing in 5.1
Always keep your audio tracks on the same lines & grouped.
Save the project again using a different name.

After your done editing here is how to replace the proxy file.
In the Project Media Bin "Right-Click" on the Proxy File & select "Replace", naviagate to your original m2ts file and select it.
Make sure again to resave this to another name.

Make your DVD
File | Make Movie | Burn it to DVD
Make sure that "Use widescreen DVD format is checked ON
Click on Next to start Rendering.
After the project is "Rendered" select the "Send to DVD Architech Studio".
After it's automatically transferred to Architect Studio Save the project in DVDA.
While your in DVDA you can simply use the defaults and burn a dvd pretty fast because your video is already dvd compliant.
4eyes wrote on 11/30/2007, 5:31 AM
There is one drawback in above method being the audio is still in the original avchd file.
But see if it works well enough to edit. If proxy files are needed for the 5.1 audio this can also be done but requires additional preparation, not easy to explain.

ADB wrote on 11/30/2007, 6:34 PM
How effective is 5.1 recording from a single location on a camera ? Does it give realistic 2D sound location ? Is voice sent mainly to the centre channel ?
OhMyGosh wrote on 11/30/2007, 10:05 PM
Didn't understand everything 4eyes, but just wanted to say thanks for writing such a detailed step by step post. If you type like me, that took a while :) Cin
4eyes wrote on 11/30/2007, 10:58 PM
OhMyGosh,
Thank you, once you start typing a step by step workflow it adds up to many steps.
Even if someone doesn't use the same suggested work flow learning the hot key commands & grouping/ungrouping takes some getting use to. Glad they have an Undo command!
I like using the Hotkeys ("W" key rewinds the video back to the beginning, same as many audio editors).
My cams are taped based HDV cams, they record in stereo, not 5.1. But I have many 5.1 HD projects
in 5.1 both hd-mpeg2 & avchd/h264. Re-working an already completed 5.1 audio project is very tricky. VMS is hard because you can't insert Dolby ac3 audio files directly. In Vegas you can.