FEC=
Satellite transponders are rather noisy communications therefore there will large be number of errors when a signal is sent through them. Because satellite transmissions are broadcast one way, the receiver cannot send a message to the transmitter to say "I didn't get that last piece of information, please re-transmit it". As a result, Forward Error Correction is used, where the transmitter sends error correction information along with the actual signal so that should errors occur, the receiver can re-generate the bit stream.
When a broadcaster transmit on a satellite, in effect they are primarily alloted certain bandwidth. Therefore if a programmer wanted to transmit two video channels via a transponder, he would use less bandwidth than a service that transmitted four. However, the bandwidth of a transponder is finite and therefore an upper limit is placed on the SR (typically between 28 and 29 MS/s). By reducing the amount of FEC information sent along with the actual data, the number of channels can be increased. However, this then means that errors are harder to correct and that the down link stations must be able to receive a certain signal strength
this what actually consider about FEC transmission , here lot of other things are also considered , modulation , encoding etc....
well picture quality dont really on dependent of FEC , if the FEC error takes place , then simply there is breakup in pic like cracks , like while playing dirty CD, not the blur or washy or pixelation
well all the matter is compression , and encoding , profile and level , framerate , aspect ratio,limunance resulution , chrominance , and video sequence headers
this what i read like this
Satellite transponders are rather noisy communications therefore there will large be number of errors when a signal is sent through them. Because satellite transmissions are broadcast one way, the receiver cannot send a message to the transmitter to say "I didn't get that last piece of information, please re-transmit it". As a result, Forward Error Correction is used, where the transmitter sends error correction information along with the actual signal so that should errors occur, the receiver can re-generate the bit stream.
When a broadcaster transmit on a satellite, in effect they are primarily alloted certain bandwidth. Therefore if a programmer wanted to transmit two video channels via a transponder, he would use less bandwidth than a service that transmitted four. However, the bandwidth of a transponder is finite and therefore an upper limit is placed on the SR (typically between 28 and 29 MS/s). By reducing the amount of FEC information sent along with the actual data, the number of channels can be increased. However, this then means that errors are harder to correct and that the down link stations must be able to receive a certain signal strength
this what actually consider about FEC transmission , here lot of other things are also considered , modulation , encoding etc....
well picture quality dont really on dependent of FEC , if the FEC error takes place , then simply there is breakup in pic like cracks , like while playing dirty CD, not the blur or washy or pixelation
well all the matter is compression , and encoding , profile and level , framerate , aspect ratio,limunance resulution , chrominance , and video sequence headers
this what i read like this
