6219 Views 9 Replies Latest reply: Jul 18, 2010 2:36 AM by Forum Friend
Thank you for your reply. Okay, if your saying I would have quality loss no matter which export option I choose then which option would be the best in terms of having the least quality loss?
My media center device supports quite a few containers and codecs:
Video Format (Containers):
-MKV, AVI, VOB
-MPEG1/2/4 Elementary (M1V, M2V, M4V)
-MPEG1/2 PS: M2P, MPG
-MPEG2 Transport Stream: TS, TP, TRP, M2TS, MTS, MOD, TOD
-.MKV, .mpg, .avi, .wmv, .divx, .vob, .tp, .ts, .trp, .dat, .iso, .ifo, .m2ts, .mov, .flv, .rm, .rmvb, .asf, .mts, .mpeg
-MPEG-4.2 (ASP@L5, 720p, 1-point GMC)
-H.264 (BP@L3, MP@HL4.1)
-VC-1 (MP@HL, AP@L3)
No loss? No dice. Almost any (every?) export from iMovie will involve some generation loss compared to the original DV stream. BTW, do you really need MPEG Streamclip in your workflow? iMovie will capture a DV stream and I think you can make the same adjustments in iMovie.
So, how to get the best result. The unknown in the equation is your player, but let's assume it'll play almost anything. I've had pretty good luck exporting to H.264 with AAC audio. This is also known as MPEG-4 or AVC video. Various flavors of this are used to make blu-ray discs (MPEG 2 or m2v is also common for the video track). These are both compressed, but do a great job of saving space while maintaining image quality.
Beyond choosing the codec, you need to choose resolution and maybe bitrate. There's no reason to use a higher resolution than you're starting with. Things like higher bitrate and multi-pass encoding will give better image quality at the expense of encoding time and disk space. And, your player may have bitrate limitations, or not have the horsepower to decompress H.264 at a high bitrate. But assuming it can handle what you're throwing at it - in part because it's SD and not HD - you should be fine. I'd start with all the "best" settings and see if it works.
The key is to test your workflow with short test files.
Thank you Kirk and Wayne.
The media player I'm using is the DViCO Tivx HD M-6600A/N which has the following video & audio specs:
Video Format (Containers)
MKV, AVI, VOB
MPEG1/2/4 Elementary (M1V, M2V, M4V)
MPEG1/2 PS: M2P, MPG
MPEG2 Transport Stream: TS, TP, TRP, M2TS, MTS, MOD, TOD
.MKV, .mpg, .avi, .wmv, .divx, .vob, .tp, .ts, .trp, .dat, .iso, .ifo, .m2ts, .mov, .flv, .rm, .rmvb, .asf, .mts, .mpeg
MPEG-4.2 (ASP@L5, 720p, 1-point GMC)
H.264 (BP@L3, MP@HL4.1)
VC-1 (MP@HL, AP@L3)
Audio Format (Container)
MPEG audio (MP1, MP2, MP3, MPA),
PCM, AC3, FLAC (Audio track in MKV)
WAV(DTS), WAVPACK, WMA (Lossless not supported)
Ogg (Audio track in MKV except for 44.1 KHz)
DTS Down Maxing
WMA, WMA Pro
FLAC, AAC, MP1, MP2, MP3, LPCM, Vorbis
"BTW, do you really need MPEG Streamclip in your workflow?"
DV will import just fine into iMovie 09 however when you render or export, iMovie uses 'single field processing' meaning every other horizontal line of the video is thrown out. In effect, reduces the sharpness of the footage. By using MPEG Streamclip, I am converting it into another format and then importing it back into iMovie.
As suggested by Kirk, I've been using Export to Apple TV and it looks pretty good (for standard definition) on my cinema display and on my widescreen tv. When I open one of the exported videos with QuickTime and Movie Inspector enabled, here's the stats:
Format: H.264, 640 x 480, Millions
Format: AAC, 2 channels, 44100 Hz
Wayne, are these the same settings you utilize? When exporting to Apple TV, the options button is greyed out or disabled so I can't make any additional changes to resolution or bitrate?
"DV will import just fine into iMovie 09 however when you render or export, iMovie uses 'single field processing' meaning every other horizontal line of the video is thrown out. In effect, reduces the sharpness of the footage. By using MPEG Streamclip, I am converting it into another format and then importing it back into iMovie."
I'm aware of the problem and I'm very curious about your solution. How exactly do you avoid the field drop issue? I thought you said you went from DV back to DV, which I thought would not have any effect on the field issue. Most other reports of working around the issue involve de-interlacing with, eg. JES Deinterlacer.
"Format: H.264, 640 x 480, Millions
Format: AAC, 2 channels, 44100 Hz
These are the AppleTV export defaults I guess? You could accomplish the same thing by an export via Quicktime, and then you'll get more control. IMHO, Apple's presets were chosen to produce "pretty good" quality at small file sizes. That's certainly a reasonable approach and they probably made a very well calculated compromise. But my preference is to sacrifice time and disk space to eke out a bit more image quality if I can.
Either way, these settings are very close to what I would use anyway, if your original video is 640 x 480. I thought my SD camcorder gave a bit more resolution before it croaked. Sorry I can't check it right now. Just be sure you're not losing resolution in the process. You could also bump the audio to 48 kHz if the input audio is at that sample rate. In the QT export, the other thing you can adjust is quality level; the default for AppleTV is probably "Good" or "Better" and single pass compression. Choosing "Best" multi-pass compression will take longer and give you a bigger file. You'll have to judge whether it's worth it. And just because you can see things on your monitor doesn't mean you'll see it on your TV - you have to test.
It's frustrating, but there really is no right answer to all this stuff, because the choices you make depend on your source and your display, and everything in between.
By using MPEG Streamclip and converting DV into another codec I am able to trick iMovie into not deinterlacing. By following Steve Mullen's eBook "The Ins and Outs of iMovie 09", I was able to workaround this field drop issue. As for JES Deinterlacer, I haven't used this tool so can't comment on it.
Thank you for the advice on Export via Quicktime. I will give a try this evening and test a few video clips with the resolution 640 x 480, 48 kHz audio and quality level of best with multi-pass compression. Then I'll take a look at both exports, Apple TV and Quicktime, on my widescreen TV to see if there's a noticeable difference.
Thanks again for your suggestions, I appreciate it.
The compression that occurs upon export via Quicktime is the reason that I am glad to have started capturing, editing, and exporting with iMovie HD 6.0.4.
I'm working only with DV-NTSC. Similar to the person who started this topic, I captured analog Hi8 tapes with a Digital8 camcorder over Firewire. I also captured miniDV tapes with a miniDV camcorder over Firewire. After editing, I used iMovie HD 6.0.4's Full Quality export to create DV Stream files (with the ".dv" extension) -- which as far as I know, is no longer available in iMovie.
I believe this Full Quality export feature does not re-encode. I don't know whether I can prove that I am correct. So far, I have not received a definitive answer from the experts whom I've asked. I started using a program called DV Analyzer to look at metadata in files with DV, which reports DV timecode and the camcorder timestamps for every single frame (as long as the file isn't too big.) This metadata is still present in files created with iMovie HD 6.0.4's Full Quality export, which is my only evidence that re-encoding does not take place.
I graduated to Final Express Express instead of later versions of iMovie. I started using Final Cut Express' QuickTime Conversion to DV Stream until learning, to my chagrin, that it re-encodes. Indeed, DV Analyzer shows the DV timecode as all zeroes, and the camcorder timestamps as all X's, in the resulting DV Stream files, which I assume is consistent with re-encoding.
I am now experimenting with importing Quicktime files with DV into iMovie HD 6.0.4. I believe this "muxes" the file back to DV Stream, no re-encoding involved (which I wrongly assumed QuickTime Conversion to DV Stream does.) I'm still using Mac 10.4.11, and don't know whether I'll be able to continue using iMovie HD 6.0.4 when I upgrade to Snow Leopard.