L3 Extended Diploma in Games Design Unit 73: Sound for Computer Games Year 1

Aims:
P2 Understand the methods and principles of sound design and production

Research and explain when you would use the following sound formats and why?

Sound file formats
Uncompressed: eg wav, aiff, au, smp, voc.
Lossy compression: eg mp3, ra, and vox.

Uncompressed file formats such as wav and aiff will be used on platforms such as blu-ray discs as they can handle having much larger files on them. Uncompressed files will not lose any data, which means that they are much larger files, but the sound quality will be much higher and you also will not lose any data from the sound. This format is ideal for platforms that can handle files of a larger size, and generally are seen on Blu-ray discs and CD's, and will be played on higher end consoles such as PS4 and the Xbox One.

Lossy compression is more suitable for platforms that cannot handle large file sizes, such as the sounds for mobile games and older, retro games. Lossy compression compresses the original file to around 1/10th of the size of the original, which means it loses a lot of data but is a much smaller file size. They are ideal for mobile games which need to be smaller in size due to the technical limitations of the mobiles.

Audio Sampling 
How can resolution and bit-depth constrain file size?

Bit depth is the number of bits of information in each sample, and it directly corresponds to the resolution of each sample. By raising the bit depth of the file, the resolution will also rise, and thus you will have a higher quality of sound. However, this comes at the cost of increasing the file size to compensate for the increased bit depth and resolution. This means that by having a higher bit depth you will have a higher resolution and quality of your sound, but the file size will be much larger, meaning that you have to be careful where you use sounds with higher bit depth. For example, a Blu-ray disc can support up to 24 bits per sample, which means it can have a higher sound resolution and quality, and can also handle the higher file size.

2. Explain what the following words mean:  

Sample rate: The amount of samples carried per second, it can be measured in both Hz or Khz.
Mono: Sound that only comes from one channel, and goes out to two speakers.
Stereo: Sound that comes from two channels to two speakers.
Surround: Sound that comes from multiple channels, and that goes to multiple speakers surrounding the listener.

Audio Limitations of Games Platforms

How can the following information limit the recording of sound?

DSP - Digital Signal Processor: Digital Signal Processing (DSP) is the study of digital representation of signals. This is a technique intended to analyze and process real time signals (or analog signals). Analog signals are those, which are represented for all values of time. Digital Signals are obtained from analog signals by a process called Sampling, which involves extracting sample values of the analog signals at regular intervals of time. This process is called Analog-to-Digital Conversion and the system performing this activity is called the Analog-to-Digital Converter (ADC). 

The following are a few of the limitations of Digital Signal Processing. 

1. Processing of signals involves more power consumption
2.  Processing of signals beyond higher frequencies (beyond GHz) and below lower frequencies (a few Hz) involves limitations
3. Information is lost because we only take samples of the signal at intervals .

RAM - Random Access Memory: Random-access memory (RAM)  is a form of computer data storage. A random-access memory device allows data items to be accessed (read or written) in almost the same amount of time irrespective of the physical location of data inside the memory.

For larger projects you will need a lot more RAM, but for smaller projects you can usually get away with having smaller amounts of RAM such as 4GB.

File Formats: File formats limit the recording of sounds in multiple ways. For example, file formats such as MP3 are compressed a lot in order to decrease the file size, meaning that you lose a lot of the information on the file when it is being recorded, whereas uncompressed file formats such as WAV allow you to record without losing any data, which gives a much higher sound quality. Furthermore, file formatting can be limited to what operating system you are using as WMA can only be used when recording on a windows machine.

Audio Output: Mono output can sound flat and boring, whereas surround sound is much more immersive for the listener. However, the issue with surround sound is that it takes a very specific set up to use, and also cannot be used with certain platforms for games, such as mobile games. Mono doesn't sound the greatest but can generally be used on most platforms. Stereo sound is a good all rounder the can be used on the majority of platforms and offers a decent listening experience with a much easier set-up, but does not offer the same immersive experience of that of surround sound.

PCM - Pulse Control Modulation: The samples are very dependent on time, meaning that you need a very accurate clock on hand in order to create the best sound. Furthermore, between the samples nothing else is taken, meaning that it might miss some information and therefore lower the quality of the sound. Finally, not choosing a value that is not correct to the analogue level for each sample can leave to errors

Audio Recording Systems 

In what types of scenario may you use the following audio recording equipment?

Multi-track recording - A method of sound recording that allows for the separate recording of multiple sounds sources or sound sources at different times to create a cohesive whole. Multitrack recording was a significant technical improvement in the sound recording process, because it allowed studio engineers to record all of the instruments and vocals for a piece of music separately. This allowed the engineer to adjust the levels and tone of each individual track, and if necessary, redo certain tracks or overdub parts of the track to correct errors or get a better "take."

MIDI-Multi instrument interface - MIDI is a protocol which can send a message to a specific instrument, meaning it tells the instrument what sound to use. With just a cable, you could play one keyboard and hear the sound of both keyboards without having to press the keys of the second keyboards.

DAT - DAT (Digital Audio Tape) is a standard medium and technology for the digital recording of audio on tape at a professional level of quality. A DAT drive is a digital tape recorder with rotating heads similar to those found in a video deck. Most DAT drives can record at sample rates of 44.1 kHz, the CD audio standard, and 48 kHz. DAT has become the standard archiving technology in professional and semi-professional recording environments for master recordings. Digital inputs and outputs on professional DAT decks allow the user to transfer recordings from the DAT tape to an audio workstation for precise editing. The compact size and low cost of the DAT medium makes it an excellent way to compile the recordings that are going to be used to create a CD master.

Analogue - Has a more real sound quality than digital as it hasn't been converted and lost data from changing form the analogue to digital. However, is more likely to have noise and interference when recording. It is also more expensive to use that digital. Good for when you want sounds to feel more authentic and real. 

Software plug-ins -  Can be used to emulate different sounds, and be used to create different music and sounds without having to record as it is all included in the software. Examples include software like Audacity and Adobe Audition.

Software Sequencer - Software sequencer is a class of application software providing a functionality of music sequencer, and often provided as one feature of the DAW or the integrated music authoring environments. The features provided as sequencers vary widely depending on the software; even an analog sequencer can be simulated. The user may control the software sequencer either by using the graphical user interfaces or a specialized input devices, such as a MIDI controller.