I had rather hoped that this thread would become redundant, through the new software update ridding us of this problem, but the Humax list of changes does not mention this fault. I notice that other posters have already reported this fault, with the new software in the new software thread. I have also been able to easily produce it using the new software.
For those not familiar with this fault, I suspect that it is present in all boxes, though it only seems to come out in limited circumstances on certain transmitters.
For anyone who want to check if their box may occasionally produce "no sound" recordings on second recordings only on Mux2 channels, the most reliable test is to:-
1. start an instant (manual) recording 1 on More4 (ch13) - not near to the end of a program
2. start an instant (manual) recording 2 on E4 (ch14) - again not near to the end of a program
3. allow both recordings to run for one minute
4. stop both recordings
5. play the More4 recording 1 - this will have sound
6. play the E4 recording 2 - if you have the fault this will normally have no sound.
I say it will "normally" have no sound, as very occasionally this test produces a recording 2 with sound. I have not yet figured out if this is totally random, or if there is a pattern to this.
This is usually not when I have first switched the box on, but later in the day, after I have done other recordings etc. It is possible that some action in using the box can prevent this fault occurring.
Got my box 3 weeks ago, tried recording E4/More4 with tuner 2 half a dozen times. Every time no sound.
Upgraded the S/W yesterday, still no sound.
The current high pressure weather system means I can receive a signal from a distant transmitter - Huntshaw Cross. Got sound for the first time. (My normal transmitter is Caradon Hill, Cornwall).
Tried Caradon again - No sound.
CHANGED THE AUDIO LANGUAGE TO SCOTTISH GAELIC - got sound for the first time!!!!!!!!
Changed back to English - got sound.
In & out of standby - got sound.
Power cycled - No sound.
Changed to Scottish - got sound.
Power cycled while still set to scottish - no sound.
Changed to English - got sound.
So changing the Audio Priority after every time the box is disconnected the mains should fix it.
The fault is would appear to be transmitter related. Caradon Hill is one of the transmitters that was without ITV News until ITV4 started 3 weeks ago. Its the same Mux as well. Must be some setting not set correctly at the transmitter?
I have tried some tests today to try to work out a pattern to this fault, though not quite as many as Barry, who mentioned in the new software thread that he had done 60.
I was also interested in what peggle had discovered above and will try playing around with the settings that he has mentioned.
I have however discovered one thing myself. That is that there is a timing issue in relation to this problem. I normally start the second recording within about 20 or so seconds from the first.
Today I thought that I would try leaving the second recording a bit longer and I have discovered that if you leave around 4 to 5 minutes before starting the second recording you get sound on recording 2.
This may explain why although it is easy to replicate this fault under test conditions, it is not reported very often by users in the normal day to day use of their box.
The fault may only occur in practice when two recordings are started fairly close together.
Perhaps those with an understanding of the technicalities of the box could explain why the fault can behave in this way.
Edit - small point for peggle. When you record More4 and E4 together you are only using one tuner. This point came up earlier in this thread. However the fault also occurs when recording another mux on tuner1 and a mux2 channel, normally E4 or More4 but also Quiz Call, on tuner2.
Others have reported failed ITV and C4 recordings but I have not had that yet.
Well done clanchief, for finding this out. When I get my unit back from Humax, I will try this out. I think that like me, you are trying to pin point exactly under what conditions this 'no sound' occurs, because it is an enigma as to why some of us can exactly replicate it, even though we are at different transmitters, yet others can't. So I will try this, however, I often do have two recordings beginning at exactly the same time, this will occur surely more often than someone beginning a recording five or six minutes after another, as most programs have the same start/ stop times, or doesn't the 'no sound' problem ever occur with timer recordings, is it only with manually set recordings?
peggles solution does not work for me, and I use Plymton which is a relay of Caradon.
clanchief solution of leaving longer does not work for me either, just left 5 mins between starting rec on More 4 and rec on E4......... no sound on E4.
It is important to note that I can only replicate no sound when carrying out instant recordings. I have now recorded over 100 today, and as yet can find no correlation as to why the 2nd recording has no sound the majority of the time.
Well done clanchief, for finding this out. When I get my unit back from Humax, I will try this out. I think that like me, you are trying to pin point exactly under what conditions this 'no sound' occurs, because it is an enigma as to why some of us can exactly replicate it, even though we are at different transmitters, yet others can't. So I will try this, however, I often do have two recordings beginning at exactly the same time, this will occur surely more often than someone beginning a recording five or six minutes after another, as most programs have the same start/ stop times, or doesn't the 'no sound' problem ever occur with timer recordings, is it only with manually set recordings?
Good point GG that people will quite ofren set up two recordings to start at the same time using the timers. However the fault is most often reported when people have used the instant manual recording method.
Also the fault only seems to occur for me when either More4 or E4 (or Quiz Call, which I can't be too bothered with) is recording2. In real live use of the box this probably does not happen very often for most people with programs that start at the same time.
I did early on in my use of the box have a "no sound" recording with timed recordings of More4 and E4 startying at the same time. I have only tried to replicate this once and that failed. The problem with doing tests using the timers is that it takes a lot of time and thus patience, even more than with instant recordings.
clanchief solution of leaving longer does not work for me either, just left 5 mins between starting rec on More 4 and rec on E4......... no sound on E4.
Barry
Pleased to see that you are also on the case of this fault as it is clearly a very tricky one to work out.
In relation to my suggestion of leaving a 4/5 min gap, I should have made it clear that for this to work it seems to depend on what channel you leave the box on during this 5 mins.
The one consistent thing that I have found, 4 times so far, is that if a new program starts on E4, which I am using for recording 2, during that 4/5 min gap, I have always so far got sound on recording 2.
Edit - small point for peggle. When you record More4 and E4 together you are only using one tuner. This point came up earlier in this thread. However the fault also occurs when recording another mux on tuner1 and a mux2 channel, normally E4 or More4 but also Quiz Call, on tuner2.
Others have reported failed ITV and C4 recordings but I have not had that yet.
Sorry I wasn't clear enough. On all my tests I have had a BBC channel on tuner 1 and EITHER E4 or More4 on tuner 2.
I realise after wading through this thread that a lot of water has gone under the bridge here, but I'll reiterate what I wrote earlier this morning. Thankfully Brian9200 directed me here.
I set my box to record Lost (E4) and The Real CSI (C5) last night, at the exact same start time.
As we had guests that were leaving as Lost was starting, I hit the pause button to stop at the beginning of Lost - by the time I got back, the box had entered play again because of the other recording I forgot about - It had run out of tuners, I guess.
I was too tired to wait for the programme to finish before viewing (Chase play please!!), so I thought I'd give it a miss and watch a few minutes this morning - No sound on the E4 recording!! Perfect sound on the C5 programme however.
I've since switched the box off and back on, etc. to no avail. There is no sound on this particular recording at all. Not good.
This is the first time this has happened since I bought the box at the beginning of the month.
Sorry I wasn't clear enough. On all my tests I have had a BBC channel on tuner 1 and EITHER E4 or More4 on tuner 2.
Understood peggle, I misinterpreted your post.
I have tried your solution but unfortunately it does not work for me, at least not consistently.
I have also run some more tests over the last couple of days and discovered that I was not correct in suggesting that the time difference between the two recordings can affect whether or not you get a no sound recording 2.
The point was however relevant as, what appears to affect if you get a no sound recording 2 is not the time difference between starting the two recordings, but what you do in between.
If go straight from More4 to E4 by pressing the channel up button and doing nothing else whatsoever, immediately after bringing the box out of standby I could consistently create no sound on E4 as recording 2. When running tests to see if a leaving a time gap made any difference I began to notice that it was not the time gap but whether or not a new program started on E4 during this time gap or whether or not I used the box to do other things while waiting that made the difference.
I have found that various actions such as playing a program from the playlist, muting and bringing back the sound and bringing up the program guide, both when on the channel of recording1 and the channel of recording2, before starting recording2, will usually, but not every time, produce sound on recording 2. Changing back and forward between the two channels several times when doing this seems to make a successful recording more likely. If I also change to a number of other channels across the different muxes if becomes certain, at least so far.
This is a workround of sorts, but not a very good one, as it is not totally predictable and involves doing too many random things. So I have been trying to isolate a reliable workround which only requires pressing about 3 buttons but so far have not succeeded.
A warning is that it is easy to think that you have found a simple workround when you haven't. The reason is the way that this fault appears to behave, at least in my experience so far. As far as I can see it operates like a software switch, which when "off" creates the no sound condition on recording 2. By doing the things that I described above, or some of them, you can turn the switch "on". If you simply then, without doing anything else, rerun the more4/E4 recording tests you will not need to do any intermediate actions to get sound on recording2. The switch appears to stay on until you use the box for other things i.e. do some of the actions above, or switch the box back to standby, which can apparently reset the switch to off.
All this makes this fault very difficult and frustrating to test for the conditions when it occurs. I am perfectly willing to believe that my provisional conclusions above are partially or even completely wrong and Barry or someone else will be along soon to "burst my bubble" again, though I will welcome that if they can throw some more light on this puzzle at the same time.
One secondary point that I have noticed today is that there is no EPG info on E4 for today on any of my boxes. I have not today so far been able to create any no sound recordings on E4, whereas I have been able to do so on More4, which has normal EPG information. This may or may not be a coincidence, I have no way of knowing either way.
I realise after wading through this thread that a lot of water has gone under the bridge here, but I'll reiterate what I wrote earlier this morning. Thankfully Brian9200 directed me here.
Thankfully, I work from home, so I can run tests if need be - Though it seems plenty has been done here already.
What's the next step?
Welcome to the small and happy band of "no sound" testers on this forum JDub800.
It is pretty certain that there is some incompatibility between this box and mux2 transmissions, which causes this fault. Only Humax and/or ITV/C4 can actually fix this fault, but if they were to read this forum and this thread it would probably help them to do this.
In the meantime it would be nice to isolate a simple workround to prevent the fault occurring. This does not seem to be an easy task.
One secondary point that I have noticed today is that there is no EPG info on E4 for today on any of my boxes.
This has been particularly bad this week. Even after the machine has been on for a few hours, quite a few channels only appear to be showing half loaded data.
I feel I can't trust the EPG on CH4, E4, etc at the moment - Quite annoying!
Hi clanchief, just letting you know that I had a nosey round the back of my computer today,and no I haven't got a serial port apart from the one that my monitor is coupled to, I have only rsb ports, so I am glad that I sent mine in. Also have been reading all the posts about many having problems downloading the new software, so heaven only knows what sort of a mess I might have made of it!! Have gone and bought that serial cable as well!!!
GG
I thought all PCs had a serial port. May be some very modern PCs do not?
I no laptops often had no serial port for many years to save on space.
Do you have an old PC or a friend or relative? Don't forget you can always take the Humax to a PC instead of the other way round = you only need to plug the humax mains lead and serial lead in = don't need an aerial or scart lead.
Like spoon261, I thought that all PCs had serial ports, though they are not very often used these days.
However for interest I have just checked the PCs here. The two fairly old desktops and the two older laptops do. The one fairly new laptop does not. One small point is that on the older laptops the serial port is hidden under a flap and some people might not realise that it is there.
You seem to have 3 options for future software upgrades.
1. Wait for the over the air upgrade
2. Follow spoon261's suggestion and use a friends computer.
3. Use a USB converter as has been discussed in this forum.
btw the connector for the monitor is quite different from a serial port and only can be used for that purpose, but you probably know that already.
This has been particularly bad this week. Even after the machine has been on for a few hours, quite a few channels only appear to be showing half loaded data.
I feel I can't trust the EPG on CH4, E4, etc at the moment - Quite annoying!
BTW, thanks for the welcome... :cool:
One suggestion for you JDub800, which may or may not work.
When my box came back from Humax this week with both the firmware and the software upgraded the EPG seemed to be working rather badly.
Then I noticed a recommendation from Barry on this forum (thanks Barry for that) to do a factory reset after all software upgrades. I did this and this seemed to greatly improve the EPG loading and updating.
Do note you will then have to put back any of your own preffered settings or changes for widescreen aspect ratio etc. I think you may also lose any reservations that you have set up for recordings, though I am not sure as I did not have any set up at the time. I can confirm though that all recordings that you have already made are not lost by doing this.
The E4 and E4+1 poor EPG data recently seems to be simply due to C4 not keeping the info up to date and nothing to do with the Humax or other freeview boxes.
Like spoon261, I thought that all PCs had serial ports, though they are not very often used these days. .
Well mine hasn't. At the back it has VGA video connection (used by the monitor) a network connector, 2 modem connectors, integrated sound connectors, 5 USB 2.0 connectors + 2 more of these at the front of the tower. At the bottom, there are fiiled in spaces where you can fit a DVI video card and /or a VGA video card, and if fitted, it looks like these may have serial ports, but they aren't fitted on mine, so it looks like if I wanted to download the software in future, that I would have to get a serial to USB cable, or wait for an OTA download.
GG
Those ARE your serial ports - serial ports can be used for a lot more besides connecting modems though but I guess that's their most usual function and maybe why the manufacturer labelled them as such.
The things that don't have serial ports any more are laptops (which is a shame as that's the kind of computer it's easiest to bring to the front room to connect to a PVR!). But, as noted previously, it's fairly easy to get USB-serial converters anyway.
Then I noticed a recommendation from Barry on this forum (thanks Barry for that) to do a factory reset after all software upgrades. I did this and this seemed to greatly improve the EPG loading and updating.
Those ARE your serial ports - serial ports can be used for a lot more besides connecting modems though but I guess that's their most usual function and maybe why the manufacturer labelled them as such.
The things that don't have serial ports any more are laptops (which is a shame as that's the kind of computer it's easiest to bring to the front room to connect to a PVR!). But, as noted previously, it's fairly easy to get USB-serial converters anyway.
Cliff
yes but Cliff, my modem ports on the tower are just telephone connectors where you would plug a telephone into the internal modem, my external modem is connected to one of the USB connections, I honestly don't have any serial connection at all.
GG:)
What I can't understand is why haven't Humax used the USB route for software downloads? Can you explain Cliff? I have used my front USB connectors (2.0) to download to my harmony remote and my Mobile, so I know that its quite easy. If this is the new way to transfer why haven't Humax used this? GG
In a piece of CE electronics you usually have a small program that runs in the first few seconds after switch on and all this program knows how to do is find the "big program", load it into DRAM memory (possibly from some "secondary storage" that's not directly accessible to the CPU) and then execute it. It probably also has routines to communicate with the outside world to receive a new copy of the "big program" and write it into that storage area (maybe nand flash, maybe NOR flash, maybe SPI interfaced memory, maybe even a hard drive?)
For it to communicate it can either be written to use only about 10 lines of C and operate a UART which is the device that "talks" up an RS232 serial cable or it could be written to communicate via USB or perhaps even via an ethernet MAC interface using TCP/IP. But USB support can run to many K of code and ethernet/TCP/IP code can be larger still.
Given that (a) the storage of this initial "bootloader" may be very limited (perhaps as small as just 16K) and (b) while everything else in the box can be riddled with bugs because the "big app" can be replaced, the bootloader can never be, you cannot risk having a single bug in it so small and simple is the order of the day.
Having said that because the size of (a) is getting larger and the stability of USB/net code for (b) is robust these days there is a move to make larger bootloaders with more intelligence. The main reason for this is actually because "big apps" continue to get bigger and passing 32MB of application code over an RS232 at 115,200 baud could take about 3000 seconds which is a LONG time and every second you spend in the factory programming these things costs money. In the old days when you could flash an app in 5 minutes it was OK - if you had a line that could program 10 boxes in parallel you could do 120 boxes per hour, 2,880 a day, 20,000 per week. But if the transfer now takes 50 minutes you could only program 2,000 per week and hence the need to use a faster transfer mechanism like USB or ethernet and "hang the added complexity in the bootloader"!
A PVR probably has about 4-8Mb of code in it and can have the image transferred in about 5-10 minutes which is still in the realms of acceptability for factory costs.
Comments
For those not familiar with this fault, I suspect that it is present in all boxes, though it only seems to come out in limited circumstances on certain transmitters.
For anyone who want to check if their box may occasionally produce "no sound" recordings on second recordings only on Mux2 channels, the most reliable test is to:-
1. start an instant (manual) recording 1 on More4 (ch13) - not near to the end of a program
2. start an instant (manual) recording 2 on E4 (ch14) - again not near to the end of a program
3. allow both recordings to run for one minute
4. stop both recordings
5. play the More4 recording 1 - this will have sound
6. play the E4 recording 2 - if you have the fault this will normally have no sound.
I say it will "normally" have no sound, as very occasionally this test produces a recording 2 with sound. I have not yet figured out if this is totally random, or if there is a pattern to this.
This is usually not when I have first switched the box on, but later in the day, after I have done other recordings etc. It is possible that some action in using the box can prevent this fault occurring.
Got my box 3 weeks ago, tried recording E4/More4 with tuner 2 half a dozen times. Every time no sound.
Upgraded the S/W yesterday, still no sound.
The current high pressure weather system means I can receive a signal from a distant transmitter - Huntshaw Cross. Got sound for the first time. (My normal transmitter is Caradon Hill, Cornwall).
Tried Caradon again - No sound.
CHANGED THE AUDIO LANGUAGE TO SCOTTISH GAELIC - got sound for the first time!!!!!!!!
Changed back to English - got sound.
In & out of standby - got sound.
Power cycled - No sound.
Changed to Scottish - got sound.
Power cycled while still set to scottish - no sound.
Changed to English - got sound.
So changing the Audio Priority after every time the box is disconnected the mains should fix it.
The fault is would appear to be transmitter related. Caradon Hill is one of the transmitters that was without ITV News until ITV4 started 3 weeks ago. Its the same Mux as well. Must be some setting not set correctly at the transmitter?
I was also interested in what peggle had discovered above and will try playing around with the settings that he has mentioned.
I have however discovered one thing myself. That is that there is a timing issue in relation to this problem. I normally start the second recording within about 20 or so seconds from the first.
Today I thought that I would try leaving the second recording a bit longer and I have discovered that if you leave around 4 to 5 minutes before starting the second recording you get sound on recording 2.
This may explain why although it is easy to replicate this fault under test conditions, it is not reported very often by users in the normal day to day use of their box.
The fault may only occur in practice when two recordings are started fairly close together.
Perhaps those with an understanding of the technicalities of the box could explain why the fault can behave in this way.
Edit - small point for peggle. When you record More4 and E4 together you are only using one tuner. This point came up earlier in this thread. However the fault also occurs when recording another mux on tuner1 and a mux2 channel, normally E4 or More4 but also Quiz Call, on tuner2.
Others have reported failed ITV and C4 recordings but I have not had that yet.
peggles solution does not work for me, and I use Plymton which is a relay of Caradon.
clanchief solution of leaving longer does not work for me either, just left 5 mins between starting rec on More 4 and rec on E4......... no sound on E4.
It is important to note that I can only replicate no sound when carrying out instant recordings. I have now recorded over 100 today, and as yet can find no correlation as to why the 2nd recording has no sound the majority of the time.
Also the fault only seems to occur for me when either More4 or E4 (or Quiz Call, which I can't be too bothered with) is recording2. In real live use of the box this probably does not happen very often for most people with programs that start at the same time.
I did early on in my use of the box have a "no sound" recording with timed recordings of More4 and E4 startying at the same time. I have only tried to replicate this once and that failed. The problem with doing tests using the timers is that it takes a lot of time and thus patience, even more than with instant recordings.
Pleased to see that you are also on the case of this fault as it is clearly a very tricky one to work out.
In relation to my suggestion of leaving a 4/5 min gap, I should have made it clear that for this to work it seems to depend on what channel you leave the box on during this 5 mins.
The one consistent thing that I have found, 4 times so far, is that if a new program starts on E4, which I am using for recording 2, during that 4/5 min gap, I have always so far got sound on recording 2.
Sorry I wasn't clear enough. On all my tests I have had a BBC channel on tuner 1 and EITHER E4 or More4 on tuner 2.
I realise after wading through this thread that a lot of water has gone under the bridge here, but I'll reiterate what I wrote earlier this morning. Thankfully Brian9200 directed me here.
My system details are as follows: -
Transmitter: Crystal Palace
Signal: 65/100
Micom: 2.02
Thankfully, I work from home, so I can run tests if need be - Though it seems plenty has been done here already.
What's the next step?
Understood peggle, I misinterpreted your post.
I have tried your solution but unfortunately it does not work for me, at least not consistently.
I have also run some more tests over the last couple of days and discovered that I was not correct in suggesting that the time difference between the two recordings can affect whether or not you get a no sound recording 2.
The point was however relevant as, what appears to affect if you get a no sound recording 2 is not the time difference between starting the two recordings, but what you do in between.
If go straight from More4 to E4 by pressing the channel up button and doing nothing else whatsoever, immediately after bringing the box out of standby I could consistently create no sound on E4 as recording 2. When running tests to see if a leaving a time gap made any difference I began to notice that it was not the time gap but whether or not a new program started on E4 during this time gap or whether or not I used the box to do other things while waiting that made the difference.
I have found that various actions such as playing a program from the playlist, muting and bringing back the sound and bringing up the program guide, both when on the channel of recording1 and the channel of recording2, before starting recording2, will usually, but not every time, produce sound on recording 2. Changing back and forward between the two channels several times when doing this seems to make a successful recording more likely. If I also change to a number of other channels across the different muxes if becomes certain, at least so far.
This is a workround of sorts, but not a very good one, as it is not totally predictable and involves doing too many random things. So I have been trying to isolate a reliable workround which only requires pressing about 3 buttons but so far have not succeeded.
A warning is that it is easy to think that you have found a simple workround when you haven't. The reason is the way that this fault appears to behave, at least in my experience so far. As far as I can see it operates like a software switch, which when "off" creates the no sound condition on recording 2. By doing the things that I described above, or some of them, you can turn the switch "on". If you simply then, without doing anything else, rerun the more4/E4 recording tests you will not need to do any intermediate actions to get sound on recording2. The switch appears to stay on until you use the box for other things i.e. do some of the actions above, or switch the box back to standby, which can apparently reset the switch to off.
All this makes this fault very difficult and frustrating to test for the conditions when it occurs. I am perfectly willing to believe that my provisional conclusions above are partially or even completely wrong and Barry or someone else will be along soon to "burst my bubble" again, though I will welcome that if they can throw some more light on this puzzle at the same time.
One secondary point that I have noticed today is that there is no EPG info on E4 for today on any of my boxes. I have not today so far been able to create any no sound recordings on E4, whereas I have been able to do so on More4, which has normal EPG information. This may or may not be a coincidence, I have no way of knowing either way.
It is pretty certain that there is some incompatibility between this box and mux2 transmissions, which causes this fault. Only Humax and/or ITV/C4 can actually fix this fault, but if they were to read this forum and this thread it would probably help them to do this.
In the meantime it would be nice to isolate a simple workround to prevent the fault occurring. This does not seem to be an easy task.
This has been particularly bad this week. Even after the machine has been on for a few hours, quite a few channels only appear to be showing half loaded data.
I feel I can't trust the EPG on CH4, E4, etc at the moment - Quite annoying!
BTW, thanks for the welcome... :cool:
GG
I thought all PCs had a serial port. May be some very modern PCs do not?
I no laptops often had no serial port for many years to save on space.
Do you have an old PC or a friend or relative? Don't forget you can always take the Humax to a PC instead of the other way round = you only need to plug the humax mains lead and serial lead in = don't need an aerial or scart lead.
Like spoon261, I thought that all PCs had serial ports, though they are not very often used these days.
However for interest I have just checked the PCs here. The two fairly old desktops and the two older laptops do. The one fairly new laptop does not. One small point is that on the older laptops the serial port is hidden under a flap and some people might not realise that it is there.
You seem to have 3 options for future software upgrades.
1. Wait for the over the air upgrade
2. Follow spoon261's suggestion and use a friends computer.
3. Use a USB converter as has been discussed in this forum.
btw the connector for the monitor is quite different from a serial port and only can be used for that purpose, but you probably know that already.
When my box came back from Humax this week with both the firmware and the software upgraded the EPG seemed to be working rather badly.
Then I noticed a recommendation from Barry on this forum (thanks Barry for that) to do a factory reset after all software upgrades. I did this and this seemed to greatly improve the EPG loading and updating.
Do note you will then have to put back any of your own preffered settings or changes for widescreen aspect ratio etc. I think you may also lose any reservations that you have set up for recordings, though I am not sure as I did not have any set up at the time. I can confirm though that all recordings that you have already made are not lost by doing this.
The E4 and E4+1 poor EPG data recently seems to be simply due to C4 not keeping the info up to date and nothing to do with the Humax or other freeview boxes.
GG
The things that don't have serial ports any more are laptops (which is a shame as that's the kind of computer it's easiest to bring to the front room to connect to a PVR!). But, as noted previously, it's fairly easy to get USB-serial converters anyway.
Cliff
Menu, 4, (Enter password 0000), 4 = Default Setting.
GG:)
In a piece of CE electronics you usually have a small program that runs in the first few seconds after switch on and all this program knows how to do is find the "big program", load it into DRAM memory (possibly from some "secondary storage" that's not directly accessible to the CPU) and then execute it. It probably also has routines to communicate with the outside world to receive a new copy of the "big program" and write it into that storage area (maybe nand flash, maybe NOR flash, maybe SPI interfaced memory, maybe even a hard drive?)
For it to communicate it can either be written to use only about 10 lines of C and operate a UART which is the device that "talks" up an RS232 serial cable or it could be written to communicate via USB or perhaps even via an ethernet MAC interface using TCP/IP. But USB support can run to many K of code and ethernet/TCP/IP code can be larger still.
Given that (a) the storage of this initial "bootloader" may be very limited (perhaps as small as just 16K) and (b) while everything else in the box can be riddled with bugs because the "big app" can be replaced, the bootloader can never be, you cannot risk having a single bug in it so small and simple is the order of the day.
Having said that because the size of (a) is getting larger and the stability of USB/net code for (b) is robust these days there is a move to make larger bootloaders with more intelligence. The main reason for this is actually because "big apps" continue to get bigger and passing 32MB of application code over an RS232 at 115,200 baud could take about 3000 seconds which is a LONG time and every second you spend in the factory programming these things costs money. In the old days when you could flash an app in 5 minutes it was OK - if you had a line that could program 10 boxes in parallel you could do 120 boxes per hour, 2,880 a day, 20,000 per week. But if the transfer now takes 50 minutes you could only program 2,000 per week and hence the need to use a faster transfer mechanism like USB or ethernet and "hang the added complexity in the bootloader"!
A PVR probably has about 4-8Mb of code in it and can have the image transferred in about 5-10 minutes which is still in the realms of acceptability for factory costs.
Cliff
GG;)