View Full Version : Divx 7 and AVCHD


Bob Kittleson
January 8th, 2009, 01:54 AM
Divx just released version 7, which now supports H.264 video and the MKV container format. This has me intrigued for the potential ability to playback AVCHD on future Divx certified devices. The MKV container format is cool because it can provide DVD-like features including menus, chapters, etc. Since Divx now supports H.264 video, maybe it will support AVCHD video without transcoding? Divx supports AAC audio instead of AC3, so audio would have to transcoded, but I'm less concerned about audio transcoding.

I'm mostly clueless about codecs and such, so I don't know if this will be possible, but I've been dreaming about something like this:

1) Start with AVCHD files produced by Cannon HF100.
2) Do basic editing with some tool like Corel VideoStudio that is capable of smart rendering to minimize transcoding, store result as native AVCHD.
3) Convert AVCHD file to Divx. Audio stream is transcoded from AC3 to AAC. Video stream is basically copied without transcoding, preserving original quality. Results are stored in a MKV file.
4) Use some tool, I don't know what, to add menus/chapters to the MKV file.
5) Resulting MKV file can be played back on computer, or on future "Divx Plus HD" certified media player devices.

Does anyone know if this is possible, at least in theory? If so, it would give us a great way to store and playback AVCHD video in full quality without the use of optical disks. Any thought or insights would be appreciated. Thanks!

Bruce Foreman
January 8th, 2009, 05:07 PM
There is a much easier way.

Edit your Canon HF100 .MTS files in any of the NLE's that will edit it natively without transcoding to something else. I use Pinnacle Studio 12 Ultimate and PowerDirector 7 Ultra.

When done with the editing, render out to HD WMV (either 1280x720 or 1920x1080 looks great). Purchase a media player that hooks up to your HD TV with HDMI and handles HD file playback. I have Western Digital's WD TV; this is a small box with 2 USB inputs and an HDMI output (also has composite if you need to connect to non HD TV) and a remote to control it.

You supply USB storage media (hard drive or other USB mass storage device) and cables.

Cost is $99 many places, I paid $129 and don't regret it.

I have an external hard drive that will be hooked up to by USB cable soon but for now I'm playing my HD WMV files from 4GB and 8GB "thumb" drives! Easy and convenient and with a small case the WD TV could even be taken over to other folks homes.

Depending on the NLE rendering times can be a bit long, one 26 minute project took Pinnacle Studio twelve hours (my quad core processor is a bit under spec according to Pinnacle) to render a 1920x1080 file but DANG does that look good on my 42" LCD TV!

PowerDirector 7 Ultra would take about 4 hours to render a 1440x810 file which has no discernable difference in resolution from the above file.

The WD TV will play most or all common file formats, I just haven't tried others. I like the picture quality I get from WMV.

Bob Kittleson
January 8th, 2009, 08:00 PM
Thanks Bruce. I have looked at the WD TV media player and it certainly has some interesting potential. I would venture a guess that in the future it will be updated to support Divx 7, even if it is not "certified". But that is perhaps a separate discussion from the codecs.

Just looking at the codecs, I don't see any advantages to WMV over Divx, other than the fact that Divx 7 is not widely supported yet. Looking to the future, I was hoping that Divx could provide some additional benefits:

1) With WMV, the video stream has to be transcoded. Even if this doesn't result in any perceivable loss of quality, it still takes a whole lot of CPU time as you noted. If AVCHD could be translated to Divx without transcoding of the video, that would make the process much faster and less painful. If AVCHD video can not transferred to Divx without transcoding, then Divx loses this advantage, but is still potentially interesting due to the other benefits below.

2) I'm not sure how well WMV supports features like menus, chapters, etc. that can provide a "DVD-like" user experience? To me, those DVD-like features are desirable. The MKV container now supported by Divx 7 does (or will) support all those features.

3) Down the road I'm guessing that we are more likely to see various Divx-capable devices on the market than WMV-capable. The result would be that Divx gives us more playback options than WMV. More options is a good thing. Even if Divx "certified" CE devices don't take off, the divx format may still see broader long-term multi-platform support than WMV.

Bob Kittleson
January 16th, 2009, 10:18 PM
To followup on this, I have exchanged some emails with Divx support, and unfortunately they said that Divx 7 is not compatible with native AVCHD video streams. They wouldn't give me any details on the reason, except to say that they have their own profile for H.264. Too bad, I'm not sure what they were thinking. AVCHD and Bluray both use H.264 "high profile". Since Divx 7 is using H.264, it would have been good to use the same profile.

Anyway, I guess we can strike benefit #1 in my last post because translating AVCHD to Divx will require transcoding of both audio and video. I think we'll have to wait and see how popular Divx 7 and the associated "DivX Plus HD" certified devices become before we'll know if it that transcoding is worthwhile.