Getting as close to a lossless conversion as possible

Question

I posted another question a few weeks ago that wasn't answered. It concerned my Sony HDD camcorder and the back that it's mpeg2 files it records (though imported fine through iMovie 08) resulted in slightly jerky footage compared to a pure burn using Canon's windows tools (you just press a "Burn to disk" on the camcorders docking station)
While I'm still not compeltely sure, I think now it's to do with the conversion, it strikes me that the burn in windows doesn't have any sort of file conversion whatsoever, the mpeg2 files are the right format for the DVD, so they get there (albeit in a vob with minimal fuss).
In iMovie my process is to import them from the camera, which (I think) converts the mpeg2 to h264, and then I can export my movie as DV which converts again, or select the "Share to media library" as large which I'm not sure on the format h264 again ?
So when I finally get the movie into iDvd it then has to go back into mpeg2 having had the guts ripped out of it. I'm still not sure why the resulting movie appears to be slightly worse in terms of the smoothness, as it's writing correctly at 25fps (I'm in PAL land) but there's a diff between the original mpeg2 file and the final result.
So my idea for fixing this issue as best I could is to convert the mpeg2 files before iMovie gets it's hands on them. SO I figure I could use Streamclip to convert to DV, but then what's the best way of then exporting from iMovie to iDVD. Can I get something close to lossless ? Any recommendations on the mpeg2 -> DV conversion in streamclip in way of the settings I should be using. I'm tending to deinterlace because it looks better on screen - but the DVD will be interlaced anyway won't it ?

Answer 1

SO I figure I could use Streamclip to convert to DV, but then what's the best way of then exporting from iMovie to iDVD.
MPEG Streamclip with the $20 QT MPEG-2 Playback component will convert your original HD camcorder files to DV. If the files do not require any editing, they can then be authored directly to DVD by iDVD. If they require editing, you have the following options:
1) Import to iMovie '08 which converts the original content to an all I-frame MPEG2/AIFF (i.e., equivalent of an M-JPEG/AIFF) and then exports the data as MPEG4/AAC for authoring to DVD as multiplexed MPEG2/PCM by iDVD, or
2) Convert to DV and import as an iMovie HD DV project. Files will be edited as DV and exported/sent to iDVD still in the DV compression format with all effects, transitions, and titles also rendered as DV for authoring by iDVD as MPG2/PCM VOB title sets. (I.e., there is one less conversion using this work flow depending on whether you consider the initial iMovie '08 import a conversion or more of an "expansion/decompression" of data.)
Can I get something close to lossless ?
This is a very subjective are of discussion and has been hashed and re-hashed in this forum many times already. Suffice it to say that either work flow can be made to produce "acceptable" results depending on numerous factors. No process of multiple conversion is truly lossless nor artifact free -- especially when going from a delivery/distributio compression format to an editing format and back to a delivery/distribution format.
Any recommendations on the mpeg2 -> DV conversion in streamclip in way of the settings I should be using.
Not really much to say here as the DV format is very standardized with relatively few user options. Any of the DV modes (DV, DVCPRO, or DVCPRO50 will work. (I tend to prefer DVCPRO for quality to files space considerations but this is really up to the user.) You, of course, will want to keep to the standard used by the camcorder -- PAL or NTSC. And you will want to flag the content properly as to anamorphic content -- especially if you plan to use iMovie '08 which previews and exports using this anamorphic flag to set the final aspect ratio. It also goes without saying that you should always re-sampe the audio content. Other than that, you should feel free to experiment.
I'm tending to deinterlace because it looks better on screen - but the DVD will be interlaced anyway won't it ?
Unless you are using a custom authoring work flow (e.g. bitVice de-interlaced source to DVD Studio Pro), I would recommend leaving this setting alone for DVD use. (I.e., I de-interlace for iPhone, iPod, TV, and/or online postings.)