Media 100 Operating Tips
You will find many sources of information on how to use the latest Media 100 features, how to create the sharpest effects, how to use different applications, or how to be a good editor. This section is devoted to the technical basics, often overlooked in the quest of creating a "wow" look. Are you letting programs get out where the colors are a bit off or if the audio isn't really clean? You don't have to be an engineer to recognize most of these problems, you just need to take the time to learn about them, just with any other aspect of editing.
Today's digital equipment requires practically no adjustments compared to ancient analog linear gear, but lack of attention to certain details will degrade your quality. Even if you don't notice it on your system, errors can add up and the result on the final VHS dub or aired program will be material that is less than the broadcast audio and video quality of which your system is capable. Clients may not be able to tell you what the problem is, but it will affect their opinion of your overall production quality.
Here then is a collection of various issues from digitizing to Mastering, that may help you improve your overall quality:
Setting Audio Levels
Maintaining Imported Color Quality, Picts and QTs
Betacam Connections and Component Cable Lengths
Setting Video Levels
Defragging Disks
File Management 101
Backing up with Retrospect
Multiple System Folders
The VX 1000 in Professional Applications
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Several postings on the Media 100 List have indicated confusion over audio levels and metering on the M100. Rightly so. Here is a bit of insight to the whys and hows of audio in a Media 100 system:
1. Digitizing. The input meters are peak reading. Due to processing time>allocated to the display, the indication may miss fast peaks. Watch a fair amount of material before digitizing to verify levels. The peak green level is 3.5 db below clipping. Not much headroom, but with a peak meter, a watchful eye can set levels accurately. Therefore, purposely going into the red is a no-no. Period. Achieving good audio performance is a challenge when you have audio and video processing on the same board and the close headroom design allows you to get the best dynamic range out of the system.
That is not the whole story. The M100 has an input stage before the input level control. Therefore if you feed it hot levels, you will clip even if the meter is not in the red. This is not a soft clip. Any clip in the M100 is hard and will distort sound, unlike analog recordings. Thus make sure your input attenuator (Hdw settings) is set properly. Best to have an audio board ahead of the M100 so you can feed audio at proper levels (EQ'd also) to M100 when the input attenuator is in the default position. With this approach and the -10 input setting the meters will accurately show the first clipping in the M100, which will be digital 16bit overrun. With the +4 setting, the input stage is strained a bit and clipping will occur in the input stage before clipping digitally. Therefore, keep the input level audio about 3db lower when using the +4 setting.
Also, take a good listen to the audio at this point. If you don't have a good speaker system, loud enough to overwhelm the sounds of the fans, then get a good set of sealed headphones. This is the point in your production where you should listen for (and fix) hum, noise and sounds that should be EQ'd. You can't do this later.
2. Track playback levels. The indication you see on each track meter represents the digital level you recorded for that track and matches the input level during recording. You can't affect it. If it clips, you blew it while recording. Use is as an "audio activity meter". The master level indicator measures the overall output level for that channel. It is calibrated the same as the input meter. If it shows clipping, you will distort. Period. The relation between track levels and master channel level depends on pan, mono, stereo settings. All level controls during editing are in series, and the output meter is the only tool you need to verify clean sound. There is no possibility of interstage clipping.
3. Output level calibration. Ideally, the meters on the M100 should match the meters on the recording VCR. This won't happen because the M100 meters read peak (to optimize dynamic range) and (most) professional meters on Sony, Panasonic are calibrated for average levels. The correct setting for recording out to a VCR is to just peak both M100 and VCR meters, as you would expect. When you send a master to dub house, they would prefer to have a standard 0 level tone on the front of the tape to set their levels, rather than listen to your whole documentary to catch the peak level. Thus you should put a calibrated tone on your leader.
4. M100 Leader Tone. This is a convenient tone, but it is not a calibration tone as it doesn't calibrate anything, in the M100 or outside.
5. Calibration Tone. You can record a proper tone though for your professional use. A problem with using tones for calibration is that the tone will read differently on a peak meter than on an average meter, which can be the source of much confusion. Using an external generator, set up a tone level into the M100 that reads exactly peak (green) level on the M100 meter at the default input gain setting. Digitize this tone. Now reduce that tone level by 10dB and record another clip. This is roughly the tone level equivalent that will produce a 0 reading on a VTR average meter, thus is the tone equivalent of average program material. You can also use the leader tones supplied with the Media 100 and modiy their levels to create calibrated max and "average level" tones.
Also, the tone of a standard bars and tone segment on a source tape played back on a professional VTR with a 0 level reading should show up on the M100 meter at this reduced level on the Media 100 peak meter, so don't try to set this tone to "0" in the Media 100 when digitizing.
Now, as you set audio levels in your program, the peak tone should match the peaks in your program material. When setting up for mastering, play back the average 0 level tone and set the master VCR for 0 level. Your program will be recorded cleanly, and consistently.
BTW, there is nothing new in these practices. Audio levels have been calibrated this way for 50 years.
Application Note Index
Maintaining Imported Color Quality, Picts and QTs
With all M100 software after 2.5 on nubus or PCI, you will need to apply a correction to any picts or QTs imported into M100 to avoid clipping whites and squashing blacks. Sometimes, if you don't have much detail in those areas, you may not notice that the black, luminance and chroma levels are wrong. But if you are doing professional work and are concerned with subtle grades of shadows or detail in white areas, you should apply a correction to any source material produced outside the M100. Material first digitized into, then exported from M100 (say, to AE or P'shop) and reimported has a built in error in the export so it will come back correctly without correction.
To apply the correction, take the imported clip into the edit suite and (Edit Clip window) and, in the pull down window, apply the following values: Luminance or Brightness -3, Contrast -19, Chrominance or Saturation -17. These values subtract out the built in error and provide a 1:1 transfer characteristice for material imported digitally into the M100.
If you export a QT of your program, these values will not be applied to the QT. Thus a QT of a mix of M100 digitized material and imported PICTS will will show up as a difference in black and white levels in the exported result.
I know how frustrating it is to get all through with a program and have a client say "Wasn't there more detail in that shot originally"...., Thus, keep your video clean through all stages and you will be rewarded.
Application Note Index
Betacam Connections and Component Cable Lengths
When outputting component video to a Betacam, a separate sync feed must go to the Betacam Ref input. This is easily accomplished by looping the Y signal thru the ref input on the way to the y comoponent input. 6" or 12" is a good length to use for the loop. Since the component inputs are terminating usually, you have to go thru the ref input first (turn off the termination). No harm nor signal loss nor timing problems will occur. A question was posted to the List, asking if this might cause a problem with unequal cable lengths.
Yes, the three component signals should be supplied thru cables of roughly equal length, yet several feet won't make a difference! At 8" per nanosecond of delay thru the cable, you can have a lot of slop before you see chroma offsets. I doubt if you could see a chroma offset of less than 40 ns. Now, timing of composite signals is a different story. 6" will make a difference of one degree at 3.58MHz. Even with composite signals, there are few situations in post production requiring the accurate timing allignment of two signals. Generally you are dealing with one signal at a time, and each video signal carries it's own sync and color (burst) reference. These days tho, most switchers requiring synchronous inputs have their own automatic timing inputs, so there are not too many people out there cutting cable to match inputs, That, (thank goodness) is a lost art.
Some of you may be ancient enough to see the humor in the story about the tech who cut all the cables to his monitors the same length so the colors would match...
Application Note Index
When digitizing video, you should be aware of what happens if your input video levels are too hot. Whites will appear "flat" and lifeless. On a lot of material this can be a subtle effect, the the results can be seen all the way through to a VHS dub. Fortunately the Media 100 has an input waveform monitor to catch such problems. Are you using it correctly?
Camcorder source tapes can have peak white video levels up to 110 IRE. Professional Betacam source tapes will have peak whites up to 107 IRE when the Bars white level is at 100 IRE. Even though the Media 100 display will show levels above 100 IRE, these levels will be clipped back to 100 IRE in the digitizing process. Older analog equipment easily passed signals up to 107-110 IRE. The acceptability of that practice was carried over to the professional digital domain where CCIR 601 allows peak white to go up to 107 IRE. While some new devices like the VX1000 limit output to exactly 100 IRE, all Betacam cameras are set to allow peak whites to go to 107 IRE. It is important that the range above 100 be preserved and not clipped, as that is where a good camera shows its stuff; highlights and white areas are reproduced with detail due to soft or adaptive white clipping, extending the dynamic range of the camera. Unfortunately, devices like the Media 100 will not pass signals above 100 IRE, thus it is important to reduce the video level before digitizing camera source material.
Thus, for maximum color fidelity, you must go through your source tapes and check to see that white peaks are coming in at or below 100 IRE. An easy compromise setting for all Betacam source tapes is to set the Bars white level at 95 IRE, which is what we do. Note: Don't let another Media 100 problem bite you: The white and black levels interact in the input settings, so always use Bars to make sure your black levels are set at 7.5 IRE after resetting the Brightness setting.
Application Note Index
If you are experiencing dropped video frames, video stuttering, or dropped audio tracks, your disk may be fragmented, caused by repeated writing over old material. First, get rid of Disk Lite and any other Norton extra that flashes useless warnings when you start or shut down your machine. These cute utilities use cpu processing time that could slow down your system when you need the speed. The objective defragmenting is to allow the Media 100 to efficiently lay down newly digitized video in an orderly fashion, without taking time to stash it in nooks and cranies left from previously erased files. Using Norton's to defrag a disk can be a long process, unnecessary and dangerous to your data. Therefore, arrange your projects such that when you clear out your media at the end of a project, you completely clear out a partition(s). Empty the trash. You have automatically defragged the disk and it will start to digitize your next project with a clean slate. It's a good idea to run Norton's at this point to repair any directory errors, etc., but it is certainly not necesssary to re-stripe or reformat the disk unless a crash wipes it out so it won't come up at all. One note, the Mac doesn't recreate a directory after you empty the trash until you restart, so do so before starting to digitize the next project.
Application Note Index
The VX 1000 in Professional Applications
(12/98) We've been using the VX1000 for a couple of years, and there wasn't anything else out there then. Interestingly, there still isn't in my opinion. I've played briefly with the Canon, but can only repeat the report of a side by side comparison that the Canon was softer in resolution. We want video that we can intercut with Betacam, so I wouldn't want any less resolution than the VX1000. Yes, you can see the VX is not as sharp as a Betacam, but its colorimetry is very well controlled and accurate from shadows to highlights. Wide range on the manual white balance when you need it, as it when shooting under greenish fluorescants or mercury vapor. Another feature which makes the VX have a "Betacam" look is the dynamic gamma correction. It is not spec'd as a feature anywhere, but you can measure it and see it in the pictures. When you are shooting with clipped or bright highligts in the scene, the VX switches the gamma curve to flatten out the curve to allow you to see shadow detail and highlight detail. About a stop and a half of extra dynamic range.
Plus, it has color bars and a number of other hidden features. So we are still very pleased with it. For extended shooting, its external DC connector makes it easy to make or buy inexpensive belt pak batteries. We use a number of $19 batteries good for over 2 hrs each.
BTW the one thing that might interest me in the XL1 is the interchangeable lenses. One always needs to go wider than the standard length on most cameras, the VX and XL1 included. However, you can't get wide zoom for the XL1, only a fixed or short range zoom. Which defeats the purpose of the interchangeable feature. For the VX 1000 you'll need an add on WA. Yes, this will drop your resolution, even if is sharp corner to corner. Make sure you can zoom through the full range using the lens. Watch for vignetting, flare, and other problems when the aperature is open. Use a WA lens hood. Note: the image stabilization won't work with the WA in place. Try to find a .5X. I haven't found a good one yet, tho the effect of this wide a lens is impressive when you need a WA. The Sony .7X #0752 is pretty good. Century Optics makes a heavy very professional and expensive WA, but it has a good deal of field curvature and the resolution is no better than the cheaper lenses.
Now for some more undocumented operational features of the VX1000:
Audio. The best way to get audio into the VX1000 is with a wireless mike, due to the unbalanced mic inputs, or use an XLR adaptor, which is big and clumsy. The Nady 351 is a good choice, clean with a wide dynamic range and small profile for the camera mounted receiver. With any input, pad the level so you don't have to reduce the camera level control below 4, or you will get input clipping distortion.
Professional Standby. Camcorders are usually on or off. When the power is on, the heads are spinning against the tape and using battery power. In professional applications "Standby" means power up for viewing the scene; "Ready" brings up the heads when you are ready to record. You can generally leave any camcorder on for a length of time without spinning the heads by removing the tape. Too bad there isn't a better solution for the near professional level VX1000. But wait - there is! It is called "Photo" mode, on the power switch. Next time you are shooting in a situation where you need on camera time for rehearsal or setting lights, just set the power switch to Photo. You can make all camera adjustments with the heads down. As you may have noticed, with the tape out, audio is set to mono and the manual level doesn't work. In our Photo mode, the audio works properly. We usually use this mode when we are using external power. On the internal battery, the camera will timeout and power down in this mode. One note: I saw one camera change exposure settings between Photo and Standby. Turned out the shutter setting was out of step. Cycling through the shutter settings corrected the problem.
Black Level. Cameras used to require Black level set up, usally adjusted before shooting each day. Cameras are more stable today and the VX1000 does not have a black level adjust. Thus, if you look at this camera's output with a scope, professionals would be alarmed to see that the setup level is 0 IRE, not the standard 7.5 IRE. Guess what. Here's the feature. In normal lighting conditions, "flare" which normally comes from scattered light in the optics tends to raise the black level, which in most cameras must be adjusted out. In the VX1000, the amount of flare is just about right to typically give you around 7.5 IRE set up. Having written this whole thing now, one can conclude, "Don't worry about it".
Focus Issues. A fair amount has been written about focus tracking problems when zooming with the VX1000. If you suspect a problem, check it out carefully and get it fixed under warranty before it becomes annoying. We have looked at several VX1000s and they all tracked focus as one would expect. You can check tracking in the manual focus mode by watching the round dot indicating focus as you zoom back from a flat surface with good vertical lines. Stop at several points and move the focus ring slightly. You should be almost on perfect focus. The dot and arrow display will indicate focus softness that you can't see looking at the picture. That is because the circuitry is looking at the high frequency content in the picture, which peaks at critical focus. Thus, even when the lens is wide, you can touch up focus accurately with the indicator. Don't try to zoom in after setting focus in wide, though.
I've seen a couple of instances of soft focus that could not be corrected with the focus ring. Not only that, they typically cleared up in a few hours. Even though the lens appeared to be free of condensation on all the visible elements, the only explanation I can guess is that during operation, heating of the camera drove a small amount of moisture to a point where it condensed on some of the inner optics. Leaving the camera in a warm area solved the problem.
With a scope on your video signal, you can verify that the camera is focusing correctly and that you are getting the correct indication from your viewfinder. That is a complicated and time consuming set up though. We have developed a clever test that you can run quickly to see if you have any problems. Use a vertical moire pattern chart, a constant pattern of fine lines of high contrast across a piece of paper will do, in front of the camera. As you zoom in and out, you will see a moire pattern appear in the viewfinder or on a monitor that shows when the frequency of the lines is interfering with the pixel pitch on the CCD pickup. This pattern is visible when you can no longer see the individual lines. Thus the indication of optical focus is quite accurate. As focus goes soft, the pattern will disappear. Use this test to verify that your viewfinder dot indicator is working properly, or that your lens is equally sharp over its normal field. Or use it to see if a wide angle adaptor is really that sharp.
If you don't want to make up such a chart, we can send you the one that we optimized for this purpose for $10.
TRV-900 and VX1000 comparison
The TRV-900 is touted by some as a replacement for the VX1000. For some users that may be true. For pro users, you should take a close look at the two cameras to decide if you are giving up too much going to the new camera. We've done a field comparison between the 2 cameras, which may help you in your evaluation.
1. Most of the features and capabilities of interest to a serious videographer that are available on the VX1000 are now offered on the TRV-900 for less money (See our web page for details).
2. However, some features are not easily accessible on the -900. Most adjustments are controlled by the thumbwheel associated with the menu selection. While this is an efficient way of getting at menu items, it does not allow easy manual operation of the camera, as in setting the iris manually in a backlight situation, or adjusting shutter speed. Audio levels must be set in this manner as well, where the VX1000 has a convenient audio level control. Audio level indicators are more accurate on the VX1000. We found under the pressures of field use, with the TRV-900 one tended to use the automatic mode, comprimising quality, rather than deal with the complexity of getting to the manual adjustments. On the contrary, the VX1000 can be run in manual mode quite conveniently.
3. The on-off switch has been simplified and the handy Betacam "standby" mode available on the VX1000 as Photo Mode, is not available. Professional Standby.
4. Because the camera is smaller, steadying the camera while handholding a shot is a challenge, and the stabilization can't make up for the extra movement.
Low light performance suffers compared to the VX1000, probably due to the 1/4" chips (vs. 1/3") used on the -900.
5. When shooting handheld, for any reasonable stability and for visibility under outside lighting, one must use the conventional viewfinder. This is smaller than the VX1000 viewfinder, and harder to see, especially if you wear glases.
Yes the technology in the TRV-900 is newer, but the implementation is better suited to non-exacting users.
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