AVCHD Transport Streams Transcoded To HD MPEG-2 Double-Image

[Jerry Jones]

Most of us using AVCHD camcorders have noticed that when we transcode our AVCHD .M2T files to HD MPEG-2, we see double-image "flutter" on the edges of subjects in motion.

Some have speculated that VideoStudio 11 Plus might be reading these files incorrectly as "frame-based" and -- as a consequence -- the render to HD MPEG-2 fails to retain fields properly.

AVCHD -- we suspect -- should be "upper field first."

Perhaps this is a flaw somewhere... either in Ulead's implementation of the MainConcept SDK or perhaps it's a MainConcept flaw.

MainConcept's Web site features an interesting comment at the bottom of this page: http://www.mainconcept.com/site/index.php?id=780

When there is video footage with field-based frames (bottom field first) - such as DV material - there are two ways of encoding it:

A) Field encoding: bottom field first
B) Whole frame

The first way generates a data stream which contains field-based frames. They include the field order: lower field, upper field, lower field etc. That means, frames will be created from both fields in the above mentioned order. The second way generates progressive frames, which don't include field information. So, whole frames will always be created, and the frames will be whole.

I wonder if the latter method is being used in Ulead software.

?

Jerry Jones
http://www.jonesgroup.net

[Jerry Jones]

So -- perhaps -- we're seeing the result of transcoding from frames whose field information may not be read correctly.

?

Jerry Jones
http://www.jonesgroup.net

[markk655]

Any way to get a response from tech support with this in hand?

[Jerry Jones]

Well, I've done some experimentation with Pinnacle Studio 11's MPEG output to see if there's a difference.

There isn't.

The only advantage that Pinnacle Studio 11 does seem to offer is the ability to choose higher bitrates for HD MPEG-2 encoding.

The Ulead software seems to impose a limitation of 18000 on 1440 resolution and 25000 on 1920 resolution.

But the interlace artifacting is still apparent using both encoders.

So I am beginning to suspect we may be seeing the disappointing limitations of consumer high definition.

Some other comparison observations about VideoStudio 11 Plus and Pinnacle Studio 11 Plus (Ultimate):

1. They seem to co-exist on my computer without conflict.

2. Ulead's software code seems more forgiving to those with slower computers; you can preview easier in the Ulead software and you have "smart proxy" if you need it and scrubbing is more responsive in the Ulead software. On the other hand, the Pinnacle software clearly warns that you need a fast computer for AVCHD editing.

3. Pinnacle offers higher bitrate encoding (advantage).

4. Pinnacle can directly import the .M2TS AVCHD files captured by the Sony "Picture Motion Browser" software while VideoStudio 11 Plus can't import those .M2TS files; Ulead's IMPORT FROM DVD/DVD-VR capture plug-in captures .M2T files from the Sony HDR-UX1.

The Pinnacle software -- at present -- does the same thing the Ulead software does... force you to transcode AVCHD to HD MPEG-2 for editing.

But Pinnacle is promising an update that will allow for AVCHD native editing/output and AVCHD discs.

It should be interesting.

Jerry Jones
http://www.jonesgroup.net

[markk655]

Jerry,

Thank you, thank you. Great and a much needed comparison!

It is very sad to hear that the AVCHD we have is an issue in both editors. I wonder if they use the same decoder.

I noticed that Ulead tended to offer better performance than S10 when working with HD footage as well. Can I also ask a few questions?

1. When you import your m2ts files into Studio, does Studio also import the surround sound 5.1? PInnacle has stated that the audio is downmixed, but I would like ot hear it from someone with the software in front of them.

2. In Studio, is the m2ts input file labelled as 1080/60i with proper fielding?

Many thanks for the comparison post. I really appreciate it.

[mlai]

I beg to differ, guys. Please try to use Nero Vision and see for yourself. Transcoding AVCHD to mpeg2HD IS DEFINITELY POSSIBLE WITHOUT ARTIFACTS IN THE OUTPUT!!!!!!

[etech6355]

The only advantage that Pinnacle Studio 11 does seem to offer is the ability to choose higher bitrates for HD MPEG-2 encoding. The Ulead software seems to impose a limitation of 18000 on 1440 resolution and 25000 on 1920 resolution.

Yes, I've also noticed I cannot manually set the project settings to 25MBS, if you import a 25MBS Program Stream video and tell VS11+ to match the settings then it will set the Project Settings to 25MBS. You can do this by making a very short HD-Slide_Video, load a picture and export it using the HDV -> HDV1080i (for PC) template. Then start a new project and load this file, answer Yes to match project settings.
*The template HDV - HDV 1080i (for PC) is full 25MBS Upper_Field_First with Mpeg Audio @ 384kbs. I would think they need to fix this not being able to manually set the video_bit_rate to 25MBS using 1440x1080. VS10+ you can set the project settings to 25MBS.

But the interlace artifacting is still apparent using both encoders.

I don't know, since VS11+ isn't displaying any fielding information is this affecting the transcode, I would think so.

So I am beginning to suspect we may be seeing the disappointing limitations of consumer high definition.

I haven't found to many limitations working with hd-mpeg2 HDV recorded to DV tape. Editing/exporting converting into intermediate codecs such as CineformHD and then back to hd-mpeg2 on my system(s) results in excellent HighDefintion video. But you should have a fast computer for the editing & conversions for big files. Playing back any High Definition Video on the computer requires a High Definition Certified Video Card along with HD certified software player(s). I've only found 2 High Def software players that work on my systems. The other software players that aren't HD Certified create arti-facts, incorrect non-smooth playback and possible freezing of HD Video files. These HD video files are good and look great played back on external hardware equipment or HD certified software players.