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Hall Of Fame
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Discussion Starter · #1 ·
The HR20, sometimes moves the rear channels to the front and drops the front, I have seen this on 2 different Dolby Digital decoder systems vendors (Sony and Philips) and I have seen it only happen on MPEG4 Streams from my local NBC and CBS feeds. I use component video and toslink/spdif for audio.

I have experienced this a few times and until last night I thought it might be a local encoding problem or a D* reencoding problem.

Last night I decided to watch my thrus night recording of ER and it started off playing the rear audio out the front channels and the front channels were missing, e.g. no voices just the background soundtrack that normally would come out the rear channels are now coming from the front channels.

We are lying in bed just bummed that it looks like we are going to miss this episode because the audio was messed up. Just to see if the non Dolby track was there I went into the setup menu and turned off Dolby Digital, and the audio track started playing normally. Ok well it isn't DD but, we can at least watch the show now. Then I said to myself, this POS has been a buggy nightmare let me turn the DD back on and see if the problem is still there with the DD sound track. I turned it back on and the audio was fine in full DD, I rewound it to the beginning of ER and the original DD soundtrack was fine, fronts in the front and rears in the rear.

The problem was not a local NBC encoding problem it was how the HR20 was miss handling the DD stream. I know other have experienced DD problems, try turning it of and on in your settings menu to see if it fixes your problem.

DirecTV, please fix your code.
 

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btmoore said:
The HR20, sometimes moves the rear channels to the front and drops the front, I have seen this on 2 different Dolby Digital decoder systems vendors (Sony and Philips) and I have seen it only happen on MPEG4 Streams from my local NBC and CBS feeds. I use component video and toslink/spdif for audio.

I have experienced this a few times and until last night I thought it might be a local encoding problem or a D* reencoding problem.

Last night I decided to watch my thrus night recording of ER and it started off playing the rear audio out the front channels and the front channels were missing, e.g. no voices just the background soundtrack that normally would come out the rear channels are now coming from the front channels.

We are lying in bed just bummed that it looks like we are going to miss this episode because the audio was messed up. Just to see if the non Dolby track was there I went into the setup menu and turned off Dolby Digital, and the audio track started playing normally. Ok well it isn't DD but, we can at least watch the show now. Then I said to myself, this POS has been a buggy nightmare let me turn the DD back on and see if the problem is still there with the DD sound track. I turned it back on and the audio was fine in full DD, I rewound it to the beginning of ER and the original DD soundtrack was fine, fronts in the front and rears in the rear.

The problem was not a local NBC encoding problem it was how the HR20 was miss handling the DD stream. I know other have experienced DD problems, try turning it of and on in your settings menu to see if it fixes your problem.

DirecTV, please fix your code.
It could just as well be the ENCODE side of the MPEG-4 from your HD Locals. I wouldn't be so quick to put it on the HR20. Local MPEG-4 providers are having a real tough time in a lot of markets getting things straight.

I've seen the same thing in local HD OTA for over a year ...they really don't have their act straight yet. I'm betting this has nothing to do with the HR20 at all.

(There's plenty to blame it for, this just may not be one of 'dem things)
 

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AllStar
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This actually happens to me also. I've tested it with both OTA and the HR20. It's really bad with my local NBC affiliate.

Its so bad that I have disabled Dolby Digital in the HR20.

I would say it is definitely on the affiliates end. I can't believe that as long as HD and AC-3 (Dolby Digital) has been around that it's still this crappy.

Pretty pathetic.
 

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Discussion Starter · #4 ·
hasan said:
It could just as well be the ENCODE side of the MPEG-4 from your HD Locals. I wouldn't be so quick to put it on the HR20. Local MPEG-4 providers are having a real tough time in a lot of markets getting things straight.

I've seen the same thing in local HD OTA for over a year ...they really don't have their act straight yet. I'm betting this has nothing to do with the HR20 at all.

(There's plenty to blame it for, this just may not be one of 'dem things)
If it was an encoding problem, it would be repeatable because the stream would be stored as corrupted on the disk, GIGO.

The reason it is the HR20 is because turning DD off and then back on fixed the problem. This means that the DD stream on the disk is good and somthing in the HR20 system is getting confused and assigning the wrong DD channel to the wrong speakers.

Get it, it is not the encoding, the exact same recording did work just by turning on, off and back on the dolby digital in the HR20.
 

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Godfather
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One of the first issues noticed with my HR20 (never before mentioned) were anomalies with DD. After a day or so, I simply turned off Dolby Digital on the HR20 and allowed my receiver to perform the decoding. Been pretty satisfied ever since but understand that if your receiver won't decode DD there will likely be issues.

John
 

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Godfather
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I don't have this problem; however, I will say that the NBC affiliate here does not broadcast their HD programs in DD. They say they can't, but both the ABC and CBS affiliates don't seem to have any problem doing so.
 

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I am not sure it is the HR20 either.

Why... the HR20 is not doing an DD decoding... it is just sending the DD portion of the encoded program out the optical. It is the Amplifiers responsibility to decode it.

It is possible that why it is different when you rewind and play again, is something in the DD stream didn't decode properly the first time on the Amplifier side of things.

But as far as I know, none of the Receivers (be it the HR20, HR10, H20, T3, ect...) actually decode the Dolby Digital.

If that was the case, it would then be able to insert the sound effects when on a program with Dolby Digital sound, and as far as know, none of the products can do that..
 

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btmoore said:
If it was an encoding problem, it would be repeatable because the stream would be stored as corrupted on the disk, GIGO.

The reason it is the HR20 is because turning DD off and then back on fixed the problem. This means that the DD stream on the disk is good and somthing in the HR20 system is getting confused and assigning the wrong DD channel to the wrong speakers.

Get it, it is not the encoding, the exact same recording did work just by turning on, off and back on the dolby digital in the HR20.
If the problem goes away when you toggle DD on and off, the next time you come across this issue please do me a favor and try hitting one of the trickplay buttons- pause or the 2-6 second jumpback button. If it 'fixes' the sound the same as toggling DD on/off then we can definitely say this is a bug. I'm tracking a series of DD bugs that were introduced by the D8 patch but so far they've just been confined to the Mpeg2 channels- if the 'trickplay fix' works then the bug is more widespread then I first thought.
 

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Discussion Starter · #10 ·
Earl Bonovich said:
I am not sure it is the HR20 either.

Why... the HR20 is not doing an DD decoding... it is just sending the DD portion of the encoded program out the optical. It is the Amplifiers responsibility to decode it.

It is possible that why it is different when you rewind and play again, is something in the DD stream didn't decode properly the first time on the Amplifier side of things.

But as far as I know, none of the Receivers (be it the HR20, HR10, H20, T3, ect...) actually decode the Dolby Digital.

If that was the case, it would then be able to insert the sound effects when on a program with Dolby Digital sound, and as far as know, none of the products can do that..
If it was not the HR20 and it was the original source stream, then the problem would be repeatable every time you played the stream.

I rewound it a couple of times to see if problem went away, it only went away after I turned off the DD and turned it back on. This is what I have done when the HR20 drops audio sometimes coming out of a FF or pause situation. BTW, I only use SPDIF/TOSLINK for all my systems, and the SAT-T60 has never once had a problem of lost DD audio coming out of a FF or pause situation, this is something else where the HR20 lacks robustness.

I agree the HR20 is not doing a DD decode like a receiver is but it is receiving a sat stream, it is extracting the MPEG4 stream and then decoding that MPEG4 streams video and audio digital data. In that decoding process it is likely that they are creating a malformed DD streams by assigning incorrect channel ID. When the DD decoder aka your audio receiver decodes the stream, audio that was originally assigned to come out the rears have now be assigned to come out the fronts.

If the DD audio channels were assigned incorrectly at the time of encoding, every time you played the stream, no matter what you did, it would always have the rears coming out the front. That is because that is how the data was sent from the original broadcaster. But since the problem was resolved by turning off and back the DD in the setup of the HR20, it is logical to extrapolate that this reset something in the subsystem that extracts the audio from the MPEG4 stream to create a DD stream.

I am not saying that what ever D* is doing to create the MPEG4 streams in the first place might be making it harder for the decoder and code in the HR20 do deal with DD streams in a MPEG4 format, hell it just might, but that is still a D* problem. But It is clear from my experience that the data in the MPEG4 recording did contain the correct information to present accurate 5.1 audio with audio going to the correct channels, so we know it was not NBC as I was eventually able to play ER in 5.1 glory by turning DD off and back on again in the HR20. This leads me to the conclusion that HR20 is the likely cause of the incorrect DD channel assignments.
 

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Discussion Starter · #11 ·
bpayne said:
If the problem goes away when you toggle DD on and off, the next time you come across this issue please do me a favor and try hitting one of the trickplay buttons- pause or the 2-6 second jumpback button. If it 'fixes' the sound the same as toggling DD on/off then we can definitely say this is a bug. I'm tracking a series of DD bugs that were introduced by the D8 patch but so far they've just been confined to the Mpeg2 channels- if the 'trickplay fix' works then the bug is more widespread then I first thought.
I did try rewinding it a couple of times to see if it restarted with channels assigned correctly.

The only DD audio problem I have had with MPEG2 streams have be a no audio situation coming out of a trick play. This is typically fixed by pausing or doing a trick play that restarts the stream. While I don't consider this a big problem it is a problem that needs to be fixed, it is unreasonable to require a trick play to get DD audio to work if it fails coming out of a trick play. In the scale of all the problems with the HR20 IMO this is lower down on the list of things that need fixed ASAP.
 
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