AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Week 10 - Transmission of digital audio in broadcast product |
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Transmission of digital audio in broadcast production<br>
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<p>The following concepts are to be researched this week:</p>
<p>• <a href="http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&oe=ISO-8859-1&c2coff=1&client=pub-8263957883925270&cof=FORID%3A1%3BL%3Ahttp%3A%2F%2Fwww.audiocourses.com%2Fimages%2Flogo2.gif%3BLH%3A50%3BLW%3A300%3BGL%3A1%3BBGC%3AFFFFFF%3BT%3A%23000000%3BLC%3A%23000000%3BVLC%3A%23000000%3BALC%3A%23000000%3BGALT%3A%23000000%3BGFNT%3A%23999999%3BGIMP%3A%23999999%3BDIV%3A%23FF8400%3BLBGC%3AFF8400%3BAH%3Acenter%3BS%3Ahttp%3A%2F%2Fwww.audiocourses.com%3B&domains=audiocourses.com&q=digital%2Baudio%2BWire&btnG=Search&sitesearch=">Wire</a>
</p>
<p>• <a href="http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&oe=ISO-8859-1&c2coff=1&client=pub-8263957883925270&cof=FORID%3A1%3BL%3Ahttp%3A%2F%2Fwww.audiocourses.com%2Fimages%2Flogo2.gif%3BLH%3A50%3BLW%3A300%3BGL%3A1%3BBGC%3AFFFFFF%3BT%3A%23000000%3BLC%3A%23000000%3BVLC%3A%23000000%3BALC%3A%23000000%3BGALT%3A%23000000%3BGFNT%3A%23999999%3BGIMP%3A%23999999%3BDIV%3A%23FF8400%3BLBGC%3AFF8400%3BAH%3Acenter%3BS%3Ahttp%3A%2F%2Fwww.audiocourses.com%3B&domains=audiocourses.com&q=digital%2Baudio%2Btelephony&btnG=Search&sitesearch=" target="_blank">Digital
telephony</a> </p>
<p>• <a href="http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&oe=ISO-8859-1&c2coff=1&client=pub-8263957883925270&cof=FORID%3A1%3BL%3Ahttp%3A%2F%2Fwww.audiocourses.com%2Fimages%2Flogo2.gif%3BLH%3A50%3BLW%3A300%3BGL%3A1%3BBGC%3AFFFFFF%3BT%3A%23000000%3BLC%3A%23000000%3BVLC%3A%23000000%3BALC%3A%23000000%3BGALT%3A%23000000%3BGFNT%3A%23999999%3BGIMP%3A%23999999%3BDIV%3A%23FF8400%3BLBGC%3AFF8400%3BAH%3Acenter%3BS%3Ahttp%3A%2F%2Fwww.audiocourses.com%3B&domains=audiocourses.com&q=digital%2Baudio%2BMicrowave%2Band%2Bradio%2Blinks&btnG=Search&sitesearch=" target="_blank">Microwave
and radio links</a> </p>
<p>• <a href="http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&oe=ISO-8859-1&c2coff=1&client=pub-8263957883925270&cof=FORID%3A1%3BL%3Ahttp%3A%2F%2Fwww.audiocourses.com%2Fimages%2Flogo2.gif%3BLH%3A50%3BLW%3A300%3BGL%3A1%3BBGC%3AFFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3AFFFFFF%3B&q=digital%2Baudio%2BSatellite&btnG=Search" target="_blank">Satellite</a></p>
<ul>
<li><a href="http://www.google.com/custom?q=Audio%2BProduction%2BFor%2BThe%2BInternet&btnG=Search&hl=en&lr=&ie=ISO-8859-1&oe=ISO-8859-1&c2coff=1&client=pub-8263957883925270&cof=FORID%3A1;L%3Ahttp%3A//www.audiocourses.com/images/logo2.gif;LH%3A50;LW%3A300;GL%3A1;BGC%3AFFFFFF;T%3A#000000;LC%3A#000000;VLC%3A#000000;ALC%3A#000000;GALT%3A#000000;GFNT%3A#999999;GIMP%3A#999999;DIV%3A#FF8400;LBGC%3AFF8400;AH%3Acenter;S%3Ahttp%3A//www.audiocourses.com;&domains=audiocourses.com" target="_blank">Audio
Production For The Internet</a></li>
</ul>
<p>General Links:</p>
<p><a href="http://www.google.com/custom?domains=audiocourses.com&q=Transmission%2Bof%2Bdigital%2Baudio%2Bin%2Bbroadcast%2Bproduction&sitesearch=audiocourses.com&sa=Search&client=pub-8263957883925270&forid=1&channel=6163154558&ie=ISO-8859-1&oe=ISO-8859-1&cof=GALT%3A%23000000%3BGL%3A1%3BDIV%3A%23FF8400%3BVLC%3A000000%3BAH%3Acenter%3BBGC%3AFFFFFF%3BLBGC%3AFF8400%3BALC%3A000000%3BLC%3A000000%3BT%3A000000%3BGFNT%3A999999%3BGIMP%3A999999%3BLH%3A50%3BLW%3A300%3BL%3Ahttp%3A%2F%2Fwww.audiocourses.com%2Fimages%2Flogo2.gif%3BS%3Ahttp%3A%2F%2Fwww.audiocourses.com%3BFORID%3A1%3B&hl=en" target="_blank">Audiocourses.com
search</a></p>
<p><a href="http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&oe=ISO-8859-1&c2coff=1&client=pub-8263957883925270&cof=FORID%3A1%3BL%3Ahttp%3A%2F%2Fwww.audiocourses.com%2Fimages%2Flogo2.gif%3BLH%3A50%3BLW%3A300%3BGL%3A1%3BBGC%3AFFFFFF%3BT%3A%23000000%3BLC%3A%23000000%3BVLC%3A%23000000%3BALC%3A%23000000%3BGALT%3A%23000000%3BGFNT%3A%23999999%3BGIMP%3A%23999999%3BDIV%3A%23FF8400%3BLBGC%3AFF8400%3BAH%3Acenter%3BS%3Ahttp%3A%2F%2Fwww.audiocourses.com%3B&domains=audiocourses.com&q=Transmission%2Bof%2Bdigital%2Baudio%2Bin%2Bbroadcast%2Bproduction&btnG=Search&sitesearch=" target="_blank">Google
Search</a></p>
<p> ;;</p>
<p>Questions:</p>
<p>1. Explain the basic difference between downloading text & graphics files
as compared to the streaming of a sound file over the internet.</p>
<p>2. Describe the process of creating a DVD master</p>
<p>3. Explain the authoring process in creating a DVD for full production film.</p>
<p>4. Describe,. with particular regard to the method of billing, the DIVX system.</p>
<p>5. Discus briefly the problems of Data Streaming on the Internet.</p>
<p>6. What is Eureka 147?</p>
<p>7. Describe the current state of DAB in the UK</p>
<p>8. What is SDARS?</p>
<p>9. Explain the term repeater.</p>
<p>10. Explain Lossy data compression.</p>
<p>11. What is meant by the The psychoacoustic model?</p>
<p>12. What is ASIASTAR?</p>
<p>13. Describe how IP Telephony works. (<a href="http://www.intel.com/network/csp/resources/white_papers/4070web.htm" target="_blank">link</a>)
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It's all in the ears. - Learn the concepts not the software.
Audio Courses is a way into the music business for you
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Mon Nov 08, 2004 6:57 am |
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iNSTiNCT2765
Joined: 05 Nov 2003
Posts: 60
Location: Denmark |
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Week 10 – Transmission of Digital Audio in Broadcast Production
1. Explain the basic difference between downloading text & graphics files
as compared to the streaming of a sound file over the Internet.
The basic difference here is that when downloading text or graphic files, the files are downloaded completely to the computer before you can use them as where a streaming sound file is played as it is downloading. When streaming, a large data bandwidth and buffer to make sure that the streaming is smooth and without any pauses due to retransmission or error correction.
2. Describe the process of creating a DVD master
Creating a DVD master is more complex than just creating a CD master. The process includes:
Audio And Video Preparation/Encoding:
The audio and video data is encoded using a MPEG2 compression method. This reduces the data rate and saves space on the disc without any loss in the quality of the media. Video is encoded using the MPEG2 Variable Bit Rate Video Encoder, which reduces the video data while obtaining the maximum quality by leaving out redundant visual information and giving more bits for complex scenes and less for simple scenes. The MPEG2 Variable Bit Rate Audio Encoder is used to encode multichannel audio (5.1 or 7.1).
Subtitling/Disc Definition:
All included language versions of the subtitles are formatted in the Disc Definition stage with the other basic information about the disc.
Multiplexing:
The multiplexer takes all the audio/video and subtitle data and combines it into one single digital data stream.
Disc Building:
The encoded and multiplexed data is used by disc building software to create a final disc image. Here, information such as file structuring, synchronization of time codes, disc branching details for interactivity and disc content specified at the Disc Definition stage are combined.
Simulation:
Before the disc is pressed in volumes for manufacturing, a computerised simulation of the disc playback is carried out to confirm the data on the disc is correct.
Channel Encoding:
After the simulation has verified that the data on the disc is correct and the disc image has been created, error correction data must be added to the data stream. This is called channel encoding and it writes the DVD formatted data stream to the Laser Beam Recorder, which is used to cut the glass master DVD.
3. Explain the authoring process in creating a DVD for full production film.
A full production film DVD usually also includes extra features, alternative scenes, different languages, and interviews besides the actual movie. And the movie has simple scenes, with not much happening visually and complex scenes, where a lot is happening which each need different amounts of the data bandwidth. The authoring process involves allocating the available bandwidth to the different strands of the film, which ensures that the maximum data rate is not exceeded. The data is then compressed, checked and the master DVD is created from this.
4. Describe, with particular regard to the method of billing, the DIVX system.
A DIVX system is used to view DIVX discs. These discs can be bought for a very low price but only allow one viewing. The DIVX system communicates with a central billing office through a modem and every time you want to watch the movie again, it will be charged to your account. Of course a DIVX disc that has unlimited viewing can also be purchased but they are more expensive than the pay-per-view type.
5. Discus briefly the problems of Data Streaming on the Internet.
As the quality of the streamed material increases, the size of the material also increases. And unlike when downloading material, the data needs to be accessed during streaming and not after it is fully downloaded to the hard disk. Therefore, when streaming the data, a large data bandwidth and buffer need to be available to ensure that the data (for example: MP3), doesn’t have any pauses during the stream.
6. What is Eureka 147?
Eureka is a technical body that represents many technical projects. The 147th project Eureka has pursued is DAB (Digital Audio Broadcasting), which is then labelled Eureka 147. This project developed and introduced a new digital transmission system that is in worldwide use and seen by many as the future of radio. DAB receivers can receive almost CD quality audio without any interference. DAB can also carry video, text pictures and data.
7. Describe the current state of DAB in the UK
The current state of DAB in the UK is that it covers 80% of the population.
8. What is SDARS?
SDARS (Satellite Digital Audio Radio System) is a broadcasting network that uses satellites as well as terrestrial transmitters where a satellite transmission is blocked (tall buildings in urban areas). The receiver therefore has two antennas. One is a monopole receiver, optimised for terrestrial reception and the other is for satellite reception and is a circularly polarized.
9. Explain the term repeater.
A repeater is a device that receives a digital signal, regenerates it and passes it on so the signal can reach further away. In digital communication systems, repeaters are placed between 2000 to 6000 meters apart since the digital signal will dissipate quicker than an analogue signal where repeaters are placed at 18000-meter intervals.
10. Explain Lossy data compression.
Lossy data compression is a format of compression where the decompressed file might not sound like the original. This is done to save space and is used when streaming audio over the Internet and is also used in telephony. The original data is compressed using a codec where some data is left out because it is redundant such as audio data that is masked. In telephony the audio bit-depth is converted to 8-bit and of course cannot be reconstructed to 16-bit sounding data at the other end.
11. What is meant by the psychoacoustic model?
The psychoacoustic model provides high quality lossy data compression by describing which parts of a digital audio signal can be compressed aggressively or removed all together without any loss in quality of the audio. This is used in most modern audio compression systems and techniques. It is used in MP3’s, Ogg Vorbis, Minidisc’s and in digital radio such as DAB.
12. What is ASIASTAR?
AsiaStar is the second satellite launched by Worldspace. It was launched March 21, 2000 and has a geostationary orbital position of 105 degrees East. It provides 50+ channels of high quality digital audio and multimedia programming directly to portable receivers that have built-in 4-inch dish antennas. AsiaStar covers most of Asia, including China, India, Indonesia, Philippines and Thailand.
13. Describe how IP Telephony works.
IP telephony uses the Internet to connect two computers together so the users can chat with each other in full duplex real-time. This of course requires a full-duplex soundcard in each computer. (a little strapped for time on this question, but I will add more to it tomorrow)! |
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Sun Nov 14, 2004 12:50 pm |
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