Forums › Home Theatre (incl HTPC) › NON-freeview TV sound quality has deteriorated

Batman

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# 20786 5-Apr-2008 23:14

In the last few weeks i swear i am hearing a super heavily compressed VBR sound from tv1 tv2 and tv3 off the airwaves! anyone knows why that's happened? hrrmph - why would BOTH tvnz and canwest do that at the same time? we;re in christchurch - wondering if it's a program engineering thing or a transmission issue or somewhere in the middle

Involuntary autocorrect in operation on mobile device. Apologies in advance.

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# 121726 7-Apr-2008 10:33

Satellite Freeview? It's been fine on my Topfield. Location shouldn't matter as long is you're in NZ. What's your signal level and quality like? Picture breaking up any?

cyril7

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# 121733 7-Apr-2008 11:56

He is refering to NON-FreeView, ie analog off air, not satellite or DTT.

Cyril

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# 122257 9-Apr-2008 09:37

Whoops. Sorry about that. Can't believe I missed that in the title! I can't hear any weird stuff on my small TV with bunny ears. Are you playing the audio through your TV speakers, or a home theatre/stereo?

richms

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# 122491 10-Apr-2008 11:08

I havent noticed anything recently, but my HT is still disconnected till I get around to moving furniture around. It sounds as bad as ever on the tvs inbuilt speakers.

Richard rich.ms

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# 122564 10-Apr-2008 16:08

It wouldnt suprise me if they have done something to the sound on analog to make it worse then the crap thats coming thru dvb-t at the moment so people dont feel they are being ripped off.

Same thing happened in the states when they started HD audio on radio stations, they started feeding the analog off the encoded and decoded data so that it didnt sound better then low bitrate aac, which FM should do, and nicam is better then FM by quire a bit.

Richard rich.ms

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# 122598 10-Apr-2008 16:53

richms: It wouldnt suprise me if they have done something to the sound on analog to make it worse then the crap thats coming thru dvb-t at the moment so people dont feel they are being ripped off.

Same thing happened in the states when they started HD audio on radio stations, they started feeding the analog off the encoded and decoded data so that it didnt sound better then low bitrate aac, which FM should do, and nicam is better then FM by quire a bit.

You need to have a word with the guy here - http://www.geekzone.co.nz/forums.asp?ForumId=83&TopicId=20902

He think the AAC bitrate is way too high and should be dropped to 48Kbit.

Perhaps you should check your software as the HE-AAC sounds better than the MP2 Audio on DTH for me.

Generally known online as OpenMedia, now working for Red Hat APAC a Technology Evangelist and Product Manager. Still playing with MythTV and digital media on the side.

richms

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# 122602 10-Apr-2008 16:57

Dropping the rate is just stupid, they should just leave the HE off since the rates are high enough to not be helped by it. Really, what is coming out of whatever I use to decode it is worse then a 32k radio stream off the net. I dont have an official settop to compare to since they are more expensive then a HTPC can be done for, I dont think I will ever have one.

The only MP2 I have to compare it against is a sky feed at a different place on different gear so it cant really be compared, but there are many artifacts on the sky audio, vs the just poor sound on dvb-t I get at home.

Richard rich.ms

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# 122655 10-Apr-2008 20:08

richms: Dropping the rate is just stupid, they should just leave the HE off since the rates are high enough to not be helped by it. Really, what is coming out of whatever I use to decode it is worse then a 32k radio stream off the net. I dont have an official settop to compare to since they are more expensive then a HTPC can be done for, I dont think I will ever have one.

The only MP2 I have to compare it against is a sky feed at a different place on different gear so it cant really be compared, but there are many artifacts on the sky audio, vs the just poor sound on dvb-t I get at home.

Problem is the DVB Spec for H.264 + AAC specifies HE-AAC or HE-AACv2

Annex H (informative):
Guidelines for the Implementation of MPEG-4 High Efficiency AAC and High Efficiency AAC v2 Audio in DVB Compliant Transport Streams

Steve

Generally known online as OpenMedia, now working for Red Hat APAC a Technology Evangelist and Product Manager. Still playing with MythTV and digital media on the side.

paradoxsm

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# 122695 10-Apr-2008 21:56

Interesting, I have heard of the setup in may countries, dropping the expensive data feeds to the Terrestrial stations and then just shoving in a pile of satellite recievers and rebroadcasting it from there.\

Considering the amazingly bad sound radio stations inflict upon us, i'm not surprised at this though!

richms

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# 122705 10-Apr-2008 22:06

It sounds like 103.4 in the waikato does that based on how it sounds so artifacty.

Sky do it for juice in auckland, with all the loverly rainfade messages that come up some times. They must have a special sky box for that feed because I have never seen it lockup like the ones that sky give to customers ;)

Richard rich.ms

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# 122937 11-Apr-2008 20:02

oh well what can i do - just have to accept it :)
those who don't agree i can't spend too much time trying to convince - it HAS become heavily compressed :) some progs more so than others.

Involuntary autocorrect in operation on mobile device. Apologies in advance.

paradoxsm

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# 122945 11-Apr-2008 20:38

I have just got sky installed and hooked up the freeview box, the satellite audio on freeview is superb, no complaints.

Things are so much more advanced now, gone are the days when sound quality mattered, for those of use whom care, the Plinius, Burr-Browns and the Missions will live on for another decade to show the peeps what we enjoyed.

dabade

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# 124177 16-Apr-2008 20:52

SHAME ON YOU FREEVIEW!!

Just to further this discussion a little, I noticed when I set up freeview DVB-T here in Hamilton that the audio was shocking. I assumd it was my decoding, but today I had a look. The TVNZ stations are broadcasting in AAC, but with a pathetic 50-60 Kbps. I kid you not, My god, a 7Mbit h.264 video, and add telephone quality audio? - what are they thinking! Maybe those that noticed a drop in analog broadcast audio are actually receiving a analog rebroadcast of the digital stream.

Incidentally, TV3 was at 128Kbit (acceptable, for a 2 channel AAC stream), and c4 had a slightly lower video bandwidth (6mbit) but beefed up the audio to 130-150 Kbit AAC (good for them, being a music channel!).

At any rate - these are all far from DVD's at 384kbit (even if it is ac3 5.1). SHame on you tvnz/kordia/freeview, wowing us with beautiful HD, and then backstabbing us with crap audio.

paradoxsm

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# 124193 16-Apr-2008 22:06

Satellite love....... stick with what you know. apart from a couple of the lo-fi sky channels the audio and video quality is superb even though it's not uber high resolution..

openmedia

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# 124216 16-Apr-2008 22:50

dabade:
SHAME ON YOU FREEVIEW!!

Just to further this discussion a little, I noticed when I set up freeview DVB-T here in Hamilton that the audio was shocking. I assumd it was my decoding, but today I had a look. The TVNZ stations are broadcasting in AAC, but with a pathetic 50-60 Kbps. I kid you not, My god, a 7Mbit h.264 video, and add telephone quality audio? - what are they thinking! Maybe those that noticed a drop in analog broadcast audio are actually receiving a analog rebroadcast of the digital stream.

Incidentally, TV3 was at 128Kbit (acceptable, for a 2 channel AAC stream), and c4 had a slightly lower video bandwidth (6mbit) but beefed up the audio to 130-150 Kbit AAC (good for them, being a music channel!).

At any rate - these are all far from DVD's at 384kbit (even if it is ac3 5.1). SHame on you tvnz/kordia/freeview, wowing us with beautiful HD, and then backstabbing us with crap audio.

For more details on HE-AAC see http://en.wikipedia.org/wiki/HE-AAC

TV One + TV 2 are 720p video and HE-AAC+ audio, Generally they average about 8Mbit for video, but audio can vary between 128 and 60K.

Media works has more capcity for TV3 and C4 as they only have two active channels on their mux.

Now you aren't really comparing apples with apples here as AC-3, AAC, HE-AAC, HE-AAC+, MP3 and MP2 are all quite different and have very different quality for the same bitrate.

Steve

Generally known online as OpenMedia, now working for Red Hat APAC a Technology Evangelist and Product Manager. Still playing with MythTV and digital media on the side.

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Annex H (informative):Guidelines for the Implementation of MPEG-4 High Efficiency AAC and High Efficiency AAC v2 Audio in DVB Compliant Transport Streams

Annex H (informative):
Guidelines for the Implementation of MPEG-4 High Efficiency AAC and High Efficiency AAC v2 Audio in DVB Compliant Transport Streams