Adobe Media Encoder is giving larger than expected file size

[james_austin]

Hi All,
I am work at a university library, and we are going through the process of converting some old vhs tapes to DVD. I have read through the guides on this site and everything has been going pretty well so far. I should also mention that I have little to no experience with video, and am learning as I go along.

To give some context:
I am using a canopus ADVC 300 and Adobe Premiere Pro to capture video in .mov. I am then using Adobe Media Encoder to export the files to MPEG2-DVD, and adjusting the bitrate and audio settings to get a file that can fit onto a single layer dvd. I am also multiplexing the files to create a single .mpg. I will be using Adobe Encore to author the DVDs, although I haven't gotten that far yet.

My problem is that I adjust the bit rate settings and audio and AME shows an estimated file size around 4000 Mb, I have been capping it around 4300Mb. I am using VBR 2 pass as this is supposed to yield the best compression to quality ratio. When the encoding process finishes, the mpg shows in finder as being 5.1Gb, too large for a dvd. Is this a common problem? is there a known amount that AME overshoots this estimate?

Any suggestions would be hugely appreciated, and I would be happy to provide any additional info.

Thanks,
James

[lordsmurf]

Your estimate may be for video only -- not including audio in the estimate.
If you're saving audio as uncompressed PCM WAV, then this would about match the numbers you're giving.

Take screenshots of all AME screens, and I'll see what may be right/wrong in your settings.

... and welcome to the site. Glad that you're finding our information helpful on your project.

[james_austin]

Thank you LordSmurf
I believe that the Media Encoder is seeing the audio component as part of the total filesize, because when I switched from PCM audio to Dolby Digital the file size goes down considerably. Of course the program could be totally underestimating the size of the audio.
I am attaching shots of the Multiplexing, Video and Audio settings. I am not using the blur filter, nor am I FTPing anything, so I don't think those matter.

And I must extend my thanks for the excellent guides and documentations on this site. It has been an wonderful resource for me in this project.
I had read in another post that the guides were going to be rewritten recently, and was wondering if that has happened already? I ask only because I am wondering if I should reference these guides, or wait until newer ones are available.

Thanks again for your help..

--james

[admin]

From what I can see in the images, all of the settings are fine. If anything, I'd suggest 5Mbps is somewhat low and compressed, given that the video is 720x480 Full D1 resolution. That usually has some level of blocks and noise. Fewer, because it's MainConceot (good encoder), but bitrate is an issue on any encoder.

Are you sure the output file is AC3 and not WAV? Run it through Gspot.
Download here: Gspot Codec Analysis Tool - AVI codec info [DOWNLOAD]

Verify it's not WAV.

Based on everything I see here, 5.1GB = video + WAV in size

[james_austin]

well, I cant use Gspot, as I am running on a Mac. However Finder does display quite a bit of info about the files. It notes that it is an MPEG file (or maybe wrapper not sure on this) and it lists the codecs used as MPEG-2 video, AC3. I am definitely selecting the Dolby Digital Stereo option. When I make the Dolby selection the file size drops significantly, but this also may remove the audio information from the estimate.

I know that 5 is a rather low bitrate setting quality wise, but in this case I am trying to fit a 2 hour movie onto a single layer dvd. When I have anything shorter than that I am generally using CBR at around 7.5 bitrate, which seems to work out fine.

I think my problem may be a combination of AME giving a poor estimate of the filesize, and some missing info about the sound file. I am trying to just undershoot by about a Gb now, and am getting closer to my target.

If anyone has a more elegant solution, or has had this experience with Adobe Media Encoder please let me know.

And much thanks to LordSmurf for his thoughts and help with this problem.

Thanks!!
James

[lordsmurf]

2 hours @ 5.0Mbps should fit under 4.3GB without a problem.

Even if you're using a Mac, you'll still want to install Wine (WineBottler), or Parallels + Windows XP.
Working with video means you'll inevitably need Windows at some point, because Mac has a very limited tool set for video work.