Tagged with faq - Personal View Talks http://www.personal-view.com/talks/discussions/tagged/faq/feed.rss Sat, 04 May 24 14:19:31 +0000 Tagged with faq - Personal View Talks en-CA The PV Beginner's Guide to Making Music - With Your Computer (For Video and Film People) http://www.personal-view.com/talks/discussion/11823/the-pv-beginners-guide-to-making-music-with-your-computer-for-video-and-film-people Fri, 21 Nov 2014 22:16:41 +0000 thepalalias 11823@/talks/discussions @Vitaliy_Kiselev asked if I could make a beginner's guide to making music using your computer (and possibly a keyboard) that's designed for people coming from a background shooting and editing video. So I'll be chipping away that big idea in little bits and pieces, starting today - with MIDI keyboards. But first, here's the short bio - since I'm currently working on this page instead of building up a site at http//www.perlichtman.com like I "should be" doing. ;)

My name's Per Lichtman. Most of you know me as @thepalalias, the creator of the audio settings used in the majority of settings available for PTool in recent years. I think PV is a great resource and joined in 2011. I also compose , produce and engineer music professionally, have my B.A. in Music Theory/Composition, have consulted for several music tech companies and am editor/contributor at http://www.soundbytesmag.net and before that at Wusik Sound Magazine (WSM).

There are users in the forum that have worked in music longer than I have and have great things they can contribute to the discussion so hopefully they'll chime in, too. Either way, we're about to help you get your feet with making music.

Part 1: An Introduction to MIDI and to MIDI Keyboards

What is MIDI?

Before we get to the really fun stuff, there's a few terms to get out of the way - and the big one is MIDI. For the past few decades, writing music on a computer has most often involved MIDI. The name MIDI is an acronym: Musical Instrument Digital Interface. During the 80s the standard was created to make sure that products from different manufacturers could communicate with each other. A MIDI signal does not carry a sound (unlike a headphone cable, for instance) but instead carries musical information - for instance, what pitches to play, how long to hold them and how loud they should be.

The thing I use MIDI for the most is to record the notes I play on keyboard into a program called a DAW. You may already have a DAW like Garageband, Reaper, Sonar, Cubase, Logic, Studio One or ProTools, but we'll cover those in a another post. The important thing about a DAW for the way we use MIDI is that it both lets you edit what you record - so that you can change notes, move them around or delete them, etc. Another important thing is that a DAW can use plug-ins to turn those notes into sounds and audio recordings. In fact you can do it all on your computer with just a mouse and computer keyboard if you want - but a lot of people (myself included) prefer to be able to play the notes in on a MIDI keyboard at least some of the time. So since you want to use the MIDI keyboard to "control" your DAW, all you really need is a MIDI "controller keyboard."

What is a MIDI Controller Keyboard?

All a MIDI controller keyboard has to do is send MIDI to another device (in our case, a computer). They do not necessarily have to be able to make sound on their own, though many do (like my old Yamaha P-60 "digital piano"). Since (generally speaking) a computer is more flexible in regards to adding new sounds than a keyboard is, I do not recommend spending more on a keyboard to get more sounds. That's for people that want to use their keyboard on stage and we'll talk more about it later. Just don't let a salesman convince you that you need an expensive keyboard with lots of sound to get realistic sounds on your computer. If you have a keyboard already, start by using that - the more you know before you spend money, the better you'll know what you actually need.

*Different Types of Keyboard Feel

MIDI controller keyboards are typically made to look like either pianos or organs, which are two instruments that feel entirely different to use. Many organs use what's called an unweighted keyboard, where the keys give virtually no resistance to your finger and our very easy to press down and play quickly. Acoustic pianos vary greatly in their feel but consistently use what's called a "weighted action" where there is a significant resistance against your fingers because the keys are actually moving hammers that strike strings - and those hammers weigh something. MIDI keyboards come with both weighted and unweighted feels, as well as a common compromise between the two called semiweighted. Finding out which of the three keyboard types is right for you is the first step in picking a keyboard.

The Pros and Cons of Different Keyboard Feels

Different people are going to want different things out of a keyboard so I'll try and explain the pros and cons instead of making a blanket recommendation. First, I'll cover weighted keyboards.

If you want to go back and forth between playing your keyboard and playing a real piano, then I would advise you to get a heavy, fully weighted keyboard. These keyboards are designed to mimic the feel of a piano and the heavier they are, the easier it is to build and maintain muscles (and muscle control) that will translate into your playing on a real piano. These keyboards are generally heavier to carry than either unweighted or semi-weighted models making them less ideal if portability is an issue.

Semi-weighted keyboards are designed to have a touch that doesn't directly emulate a piano, but still provides some resistance. If you don't plan on playing an acoustic piano much or just happen to like the feel of a semi-weighted keyboard better, then these can be a great option. This is the middle road and you'll find a huge number of options available.

Unweighted keyboards are the cheapest to manufacture, the lightest to carry and can be made much smaller than other models. For all these reasons, many people get them as either their first keyboard, or as a second "travel keyboard". These keyboards feel nothing like a real piano at all and tend to frustrate pianists looking for "something to practice on". I know this from experience. ;)

The keyboard weight also affects how you play. Some professional stage keyboardists have commented that they find it easier to play quick ornaments, like trills, on unweighted and semi-weighted keyboards than on weighted ones, especially in certain popular genres. Conversely, most pianists I've talked to find it much more difficult to play classical music on anything other than a fully weighted keyboard.

A Few Thoughts on Keyboards I've Used

Within each feel there's going to be a lot of variation, not only from manufacturer to manufacturer but also from model to model. In terms of the heaviest feels, I would to certain models by Yamaha and Roland (more on that in a future post), while my experience with lighter feels is less extensive. I still use a Yamaha P-60 that I received as a gift over a decade ago, so it's not like buying a digital camera. If you get one you like, you can keep it a long time.

One of the lightest keyboards I've personally used is a Korg Microkeys with a very limited range. This is not a keyboard I play because I like the feel - it's a keyboard I use when I want something light and tiny to take with me somewhere. It's inexpensive, so I don't worry about breaking it or having it stolen in the same way I would with a "favorite" keyboard, so there's something to be said for that, too.

*How Many Keys?

The length of a keyboard is primarily determined by two things: the number of keys and the size of the keys. A normal full size piano has 88-keys so MIDI keyboards normally max out at 88-keys. 88-keys covers a range of 7 octaves and two semitones in standard western tuning. There are also 76-key (6 octaves and 2 semitones), 61-key (5 octave), 49-key (4 octave), 37-key (3 octave) and 25-key (2 octave) keyboards.

The fewer keys there are on the keyboard, the less space it needs to take up. At the same time, as the number of keys decreases, so does the range you can play in. Many acoustic instruments (including the human voice) have ranges that exceed three octaves, so if you're using a 25-key keyboard, you may find that you start your melody line on one end of the keyboard and then hit the other end before you reach the top of your line. That's why many small keyboards use transpose buttons.

Transpose buttons let you change the range your keyboard plays in at any time. This is a helpful workaround, but it still means one of your hands off the keys to change the setting - and we haven't even gotten into adding chords to that melody. For that reason, I would say that unless you really need to save space (or are very tight on money), that it's easier to play on keyboards with a minimum of 49-keys.

Key Size

As mentioned before, another big size factor is the size of each individual key. Standard or full size keys are designed to fit the size and spacing of a concert piano. However, some keyboards use keys that are a fraction of full size. If you're used to playing on an acoustic piano, these will feel cramped and you'll have to adjust your technique every time you go back and forth between full-size and reduced size. These are the big disadvantages.

The advantages of the smaller keys are that keyboards that use them can be manufactured to be smaller, often at a lower cost (which sometimes translates into a lower price for the consumer). If money and/or space are the biggest part of your decision making process, then feel free to consider them. But if you have the goal of eventually playing piano, you can give yourself a headstart by choosing full-size keys.

How do MIDI Keyboards Connect to A Computer?

The simplest way to connect a MIDI keyboard to your computer is to get one that can use a USB cable to send notes to the computer. Many new keyboards support this method and it means you won't have to buy any additional hardware. Devices that use this approach typically either use a standard USB driver or come with one you'll have to install. As long as you have a compatible driver for the operating system you use, you can take the keyboard and a USB cable and go from one computer to another without additional hardware.

Some keyboards have MIDI cable ports instead of USB cable ports (or in addition). The simplest way to connect these to your computer is to get a combination cable/MIDI interface, like the Roland UM-One, M-Audio Uno or Art M-Connect. I haven't used any of those models, but they run $30-50 USD a piece and allow you to connect your device directly to any computer with a USB port and operating system that the product's driver support.

MIDI ports can also be connected to a MIDI interface within certain audio interfaces or to a dedicated MIDI interface. If you already paid money for a professional or prosumer audio interface that has these ports, you can just a standard MIDI cable - which start as low as $6-7 USD.

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BlackMagic: FAQ maintenance topic http://www.personal-view.com/talks/discussion/3011/blackmagic-faq-maintenance-topic Wed, 25 Apr 2012 18:51:58 +0000 Vitaliy_Kiselev 3011@/talks/discussions We now have FAQ about upcoming Black Magic Cinema Camera:

http://www.personal-view.com/faqs/blackmagic-cinema-camera/blackmagic-cinema-camera-faq

I am making this topic to help maintaining it in always actual state.

Let me know any questions or information that you have.

P.S. If you want to help me maintain it on Wiki send me PM.

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GH1 Firmware Hack FAQ http://www.personal-view.com/talks/discussion/117/gh1-firmware-hack-faq Fri, 20 May 2011 09:42:26 +0000 zcream 117@/talks/discussions GH1 has the best recorded image out of ANY camera less than 10K. Here is my article about installing the firmware for noobs.

The article also appears here.
http://www.mishra.tv/wordpress/?p=95

This is a very simple tutorial that will attempt to organize everything for first time users.

Video is essentially a sequence of still images taken 24,25,30,50 or 60 times a second. Also, during a video recording there is a spatial relationship between successive stills. The camera records in 2x formats – AVCHD and MJPEG.

MJPEG records video as a sequence of JPEG stills (also called an intraframe codec). Hence, it can be easily edited on any computer. On the flipside, it is less efficient than AVCHD for storage. Both the GH1/GF1 only record 30p videos in MJPEG.

AVCHD uses the spatial relationship to record each frame as a DIFFERENCE of stills (called an interframe codec). This encoding is called a Group of Pictures (GOP) encoding. So, the sensor takes its snapshots which it passes to the encoder. The encoder takes the first snapshot, saves it as a still, and calls it an I-frame. The next few frames are encoded as a difference frame, encoding only the regions that have changed. These are called P-frames. There are also D and B frames, that are variations on this theme. If there is lots of movement (i.e. foliage on a windy day, or ocean current), the encoder gets stressed trying to calculate P-frames. This causes errors while using your camera.

Finally, we need to understand colorspace. If you have ever painted, you know that all colors are composed of the primary RGB (Red-Blue-Green) spectrum. So, a basic representation of a color image involves at least 3 values for R, G and B. Depending on the color depth (8,16 or 32-bit), this can mean 24, 48 or 96-bits per pixel. That is a LOT of information. Hence, another colorspace is used for encoding stills and video – called YCrCb. The intensity of light on a pixel is called luma, and the color value (a composite of Red, Green, Blue) is called chroma. In practice we only need 3 values, Y (luma) Cr (Y – Red) and Cb (Y-Blue). The value of green can be derived from these 3 values. Now, the human eye is more sensitive to luma than chroma. So, a common scheme is to reduce the sampling for Cr and Cb. This is called 4:2:2 colorspace, where luma is sampled at twice the rate of chroma. A more efficient alternative is to sample Y at twice the rate of Cr and Cr at twice the rate of Cb. This is called 4:2:0 sampling. Obviously 4:2:2 sampling will stress the sensor circuitry and cause more errors.

MJPEG can offer 4:2:2 or 4:2:0 sampling, while AVCHD can only offer 4:2:0 sampling.

Finally we need to understand interlaced vs progressive footage. Consider standard NTSC rates of 60i or 30p. In progressive mode, a sequence of 30 still images are written to disk in 30p mode. In interlaced mode, the encoder reads the odd or even lines on each image. Thus even though the sensor is sending out 30 images each second, the encoder takes each image and encodes the odd lines on odd frames, and even lines on even frames. In interlaced mode, there are 60 calls to the encoder to write 1920×540 resolution images per second. In progressive mode, there are 30 calls to the encoder to write 1920×1080 resolution images per second. Obviously a progressive encoding for the progressive image generated by the sensor is more efficient but also more stressful for the encoder.

Having read this, lets start with the hack.

1. Use a Windows PC for this. Things can work with Parallels or other emulators on a mac. Winebottler can cause a problem where the bottom part of the hack utility (with options for various hack settings) is not seen.

2. Download the LATEST version of ptool from here. https://www.personal-view.com/faqs/gh2-hack/ptool-software Unzip it into a GH1 hack directory

3. In the past, we had to modify each individual setting. It was a tedious task to setup a GH1 or GF1. Now we can have multiple settings files that can be used, as long as they are in the same directory as the ptool. Check out the Ptool FAQ and the various settings available.

4. Now I will offer what I do for my shoots. I use AVCHD as its the only choice for 24p/25p footage. 30p is pointless unless all you need is to post videos on Vimeo. There are 3 hacks, available for the GH1 which offer Reliable, Turbo and Extreme modes of the hack (my terms). I use 3 cheap SD cards, some 16MB cards I have lying around. Format them in the camera and load 1 setting per card as shown in the FAQ above. Use a sharpie to write down Reliable, Turbo and Extreme. The 3 settings are provided the lpowell.

They are :
Reliable 2 - 40Mbps Reliable In-Camera Playback Patch - highest reliability for all camera models and all SD card types
Direct Reliable patch download.

Blackout-Powell Native 24p Patch v2

Extreme - 100Mbps Max Latitude Native 24/25p Patch v2- GH1 only, Class 10 SD cards, Native 24p FHD, 30p SH mode

All three patches are switchable between NTSC and PAL modes, and support multiple language selection, unrestricted recording time, and third-party batteries.


The robustness is obviously less for Extreme and Turbo than Reliable. At night, or for places indoors use the Extreme patch. If it does not work, use the Turbo patch. For dense foliage, or clip with running water use the Reliable patch. lpowell has stated that the Extreme patch is at least as robust if not more than the Turbo patch. Since the patch is new, I may update this information after it has been widely tested.

5. After recording, you may decide to view the video files for errors or out of curiosity. Please download cbrandin’s StreamParser - for more fun.]]>
Wiki discussion http://www.personal-view.com/talks/discussion/1644/wiki-discussion Tue, 06 Dec 2011 01:41:37 +0000 cyfernoa 1644@/talks/discussions
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