#Premier 4.0 & Compresion
11 messages in this thread
Hello,
I have FAST's Movie Macchine Pro w M-JPEG and Adobe Premier 4.0.
Does Adobe ever answer mail addressed to them in their Application Fourm? I've
posted a couple of items for them, and haven't gotten any reply.
My problem/question/thought:
With the FAST stuff I can capture video and audio just fine. In the tests I've
been conducting, 20 secs of video & audio takes about 10,700,000 bytes of disk.
Now, I expect that when I capture a pair of 20 sec clips, and edit them
together into a single .AVI file, I should get a file of about 21,400,000
bytes.
I'm trying to get to this because I'm losing enough resolution at 16:1
compression when I create the clips. I'm not interested in further
compression. But, so far, the resulting 40 second clips are occupying only
13,300,000 bytes or so – not much more than the space of the original clips!
Further, the resulting 40 sec clip doesn't look as nice as the individual 20
second clips, and of coursse, none of the three look like the original!
What am I doing wrong?
The following are the configuration parameters I'm using in FAST's stuff and
Premier:
FAST's Movie Capture:
30 frames a second, (29.97 for some reason doesn't work)
1/2 Image Size,
320×240,
Keep Aspect Ratio,
16:1 compression,
8 bit stereo at 22Khz.
Premier 4.0's settings:
Timebase: 29.97
Compression:
Settings: AVI
Method: FAST M-JPEG
Depth: Millions
100% Quality
Frames: 30
Data rate: Nothing checked
Preview Options:
Size: 320×240 in front
Video rate 30
Mode: Effects to disk
Type: Full Size Frame
Process at: Same as project
Video filters: On
Audio rate: 22KHz
Format: 8 Bit – Stereo
Build: Disk
Play: Disk
Audio Filters: On
Output Options:
WorkArea as AVI Movie
Video Size: 640×480 4:3 Aspect is NOT checked!
Type: Full Size Frame
Audio rate: 22KHz
Format: 8 Bit – Stereo
Type: Uncompressed
Interleave: 1 Second – whatever that means?
Thanks for your help! Bill Metzger, San Diego
Bill,
There are others here that I think will give you a better answer but I have
seen a post similar to yours before and the answer was that Adobe was
re-compressing the all-ready compressed digital streams when it created the AVI
movie file. Under the compression options of Premiere is there a way to turn
off compression entirely? I see that you do have it turned off in the Output
Options screen (now that I am half-way throught this reply <grin>) because
maybe Premiere is doing something to the source on the way in or in the editing
process itself.
-John
Bill,
Don't know if this will help, but what I've managed to get out of Adobe, Intel
(I'm currently using their indeo board), and Microsoft, the "ideal" way to
manipulate video is as follows:
1. Capture with no compression whatsoever.
2. Assemble or edit various uncompressed AVI's using Premier or other editor.
3. Now compress the final AVI just once. At this point the audio interleave
should be set for 1:1
Of course this makes you wonder why they sell boards with hardware compression
on the fly on input, but it does look nice on promo copy on the outside of the
box. <g>.
I've been trying to find out about MPEG or MJPEG (are they the same?) video
compression for output back to a video tape recorder. Spent ten hours on the
phone last Friday and got the impression that everybody has something to sell,
but whether any of it works is a good question.
I spoke to Adobe and they "suggested" boards from Alpha (MegaMotion), Diamond
(VideoStar) and Fast (MovieMaker Pro) and kept mumbling about Miro.
Have you managed to input video from a vcr, edit, and then output back to tape?
If so what does the output look like?
I'd be happy if it looks like a 3rd generation video copy (source > master edit
> VHS copy). It seems like MPEG is the way to go, but I'm really confused as to
whether such an option exists in the under $1M market.
Richard Robinson
Richard:
Perhaps I can start to answer some of your questions…
>>Of course this makes you wonder why they sell boards with hardware
compression on the fly on input, but it does look nice on promo copy on the
outside of the box. <g>.<<
The answer is data rate. Video is a lot of information every frame and there
are, at a full NTSC frame rate, 30 fps. If you try to save 30 uncompressed
frames or pictures a second to a hard disk, you'll need very good through-put.
With a standard system, they're likely to be small pictures or you're likely
not to get all 30 frames. Compression technology reduces the amount of data
the system needs to store. Sure, that may mean quality is likely to go down
depending on the amount and quality of compression, but at least you're more
likely to get all the frames.
MPEG and M-JPEG are not the same. Both are based on the JPEG standard (used
for compressing still photograph) but they're different after that. For NTSC
video, M-JPEG, or Motion-JPEG, is simplistically like storing 30 JPEG frames
each second. MPEG on the other hand stores a JPEG frame every, say, twice a
second (these are called I-frames) and stores only differences in the rest of
the frames (these are a combination of B- & P-frames). In other words, if a
person is walking past a solid white wall, MPEG will store the white wall only
in the I-frames. The rest of the frames will ignore the white wall, where it
is the same, and store just the man walking. That means much lower data rate
because there much less information needed. BUT, you don't have every frame
for editing. Also, MPEG is much more difficult to do in real time (see New
Media Mag, current issue).
>>I spoke to Adobe and they "suggested" boards from Alpha (MegaMotion), Diamond
(VideoStar) and Fast (MovieMaker Pro) and kept mumbling about Miro.<<
All will work. If you're going back out to tape, I'd say the miro card has the
best picture quality. If you're going not going out to tape (ie. multimedia
type app.) you'll do better with another. For multimedia, though NOT for
printing to tape, I'd add the Intel Smart Video Recorder Pro to the list.
That's just a start. For what it's worth…
Jeff Sauer
Jeff,
Thank you for the information. Once less Advil I'll have to take today <g>.
Richard
If your output options are the same as what you used when capturing
the clips, Premiere will just copy frames from the original clips to
your output movie. However, if they differ, Premiere has to recompress
frames, possibly resulting in the reduced image quality you're seeing.
Make sure your output options match those of your source material.
This includes: frame size, frame rate, codec and color depth. In
your message, you have your capture size as 320×240 and your output
size as 640×480. If this is true, this could be causing the problem.
Try changing your output size to 320×240.
-Larry
Larry:
>Try changing your output size to 320×240.<
Is that ouput size sufficient for output to video? Pardon my ignorance, but I
thought you needed 640×480 output to get a video picture that looked like
anything…
Tim Liebe
Tim:
I was mostly just replying to Bill's concerns about recompression.
320×240 can give you reasonable consumer quality, basically
comparable to VHS. For example, the Miro can output 320×240
to NTSC and it looks OK – not great, but definitely usable.
Maybe something like a second generation VHS copy.
-Larry
Larry:
>320×240 can give you reasonable consumer quality, basically
comparable to VHS.<
Thanks for the clarification!
Best,
Tim
Timothy, when you output your video file using a 320 X 240 clip size, you need
to specify "Zoom X 2" "using Software" in the Print to Video dialogue box.
Larry said that if you record your video and edit your video both in 320 X 240,
then you will only be compying your video frames instead of recompressing them.
That's true unless you have transitions and filters added to your video clips;
then Prmiere recompresses the video. AT which point, you might as well specify
a data transfer rate, (pick a high one, as high as your system can stream out
smoothly).
The guy to talk to at Adobe is Nick Schlott on 71311,2050, you can sometimes
find him on this forum, but he is really good at answering in the Adobe Forum,
unless he is buried in getting a release of Premiere Mac/Windows out the door.
He is one of the principal engineers of the product, his name is on the
credits, and there's even a video of him on the Premiere 4.0 CD. So, basically
he knows his stuff.
Best,
Scott
Scott:
>The guy to talk to at Adobe is Nick Schlott on 71311,2050<
Thanks for all the info!
Best,
Tim