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digitalscoobiedoo

Listed below are comments made by digitalscoobiedoo between Thursday, 10th December 2009 and Monday, 21st December 2009.

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BBC HD Picture Quality: some myths laid to rest 00:59am on 21 Dec 2009 There are a lot of folks raising complaints on here to www.bbc.co.uk/complaints and getting fobbed off with a standard response. Just to let you know if you have the right to a specific reply from senior management to any points you raise. Just say their standard response doesn't solve your problem and asked for it to be raised with Senior management, and then subsequently if that doesn't satisfy you, BBC Trust.
BBC HD Picture Quality: some myths laid to rest 10:54pm on 16 Dec 2009 I know a lot of new people are reading this blog today. The link below takes you to a summary I did of the technical facts behind the picture quality getting worse.

http://www.zen97962.zen.co.uk/downloads/BBC_HD_bitrate_cuts_Powerpoint_2003_iss2.pdf

(thanks to Paul G for hosting)
BBC HD Picture Quality: some myths laid to rest 10:24pm on 13 Dec 2009 Mike - Disagree. They haven't altered it at all.
BBC HD Picture Quality: some myths laid to rest 10:01pm on 13 Dec 2009 Re next FOI
Suggest keeping the wording as unspecific as possible - e.g. Any discussion internally within the BBC - including but not limited to emails - around HD picture quality since July/August. So for instance, a Producer or Director may have complained to someone in the technical department about how their program looks on screen.
The Hitchhiker's Guide to Encoding: And Another Test...(Or PSNR and all that...) 8:20pm on 10 Dec 2009 Sorry , above post I got mpeg 2 and 4 the wrong way around.
The Hitchhiker's Guide to Encoding: And Another Test...(Or PSNR and all that...) 8:20pm on 10 Dec 2009 @mikerb
I think that's pretty much what they did. The 2:1 figure comes from the EBU I think but they also state that 12.1 Mbps minimum is required for non intensive 1440 broadcasts. Bear in mind that the old BBC HD level 16mbps was a BBC , not EBU derived setting. This in itself was substandard setting IMO, so the BBC have tried to half a substandard setting in the siwtch from mpeg 4 to mpeg 2. And the result - the negative reaction from viewers we have seen over the past 4 months?
The Hitchhiker's Guide to Encoding: And Another Test...(Or PSNR and all that...) 7:29pm on 10 Dec 2009 I've thought of a new question to add to the list if you don't mind:

1. Why was the higher bit-rate not sustainable?

2. Why can't we have a short period back on the higher bit-rate as a simple test?

3. Why can't the satellite transmissions be statistically multiplexed to make better use of the available bandwidth on the transponder?

4. Why is BBC HD being transmitted in Scandinavia at a higher resolution and a higher bit-rate than that being transmitted to the licence paying public in the UK?

5. Will the BBC be increasing the bitrate in the near future? Yes?No

6. Will the BBC be changing the picture format to 1920x1020? Yes/No

7. Will the BBC be introducing a variable bitrate? Yes/No

NEW:
8. What happened to picture quality when you tested higher bitrates on the new encoder?
The Hitchhiker's Guide to Encoding: And Another Test...(Or PSNR and all that...) 7:20pm on 10 Dec 2009 If these questions aren't answered I suggest we go down the Freedom of Information act route - that way they will have to be answered in 20 working days at least.

1. Why was the higher bit-rate not sustainable?

2. Why can't we have a short period back on the higher bit-rate as a simple test?

3. Why can't the satellite transmissions be statistically multiplexed to make better use of the available bandwidth on the transponder?

4. Why is BBC HD being transmitted in Scandinavia at a higher resolution and a higher bit-rate than that being transmitted to the licence paying public in the UK?

5. Will the BBC be increasing the bitrate in the near future? Yes?No

6. Will the BBC be changing the picture format to 1920x1020? Yes/No

7. Will the BBC be introducing a variable bitrate? Yes/No
The Hitchhiker's Guide to Encoding: And Another Test...(Or PSNR and all that...) 6:55pm on 10 Dec 2009 Andy,

There don't seem to be any tests on the core topic of all the complaints - BITRATES. i.e. whether restoring higher bitrates will improve the picture quality.

You mention one test on high noise material where you did vary bitrate but no tests on normal material -say sports or natural history which we know is difficult to encode.

Have you tested what happens to the picture quality when you increase the bitrate or must I go down the Freedom of Information Act route again?

If you haven't done tests that would suggest you put cost before picture quality on the HD channel.

So, have you tested what happens when you increase the bitrate?
The Hitchhiker's Guide to Encoding: And Another Test...(Or PSNR and all that...) 6:42pm on 10 Dec 2009 Can someone technical comment on the methodology used here?

I thought that to select a bitrate you need to do this: (excuse the simplistic language here, I've forgotten the correct terms):

1. Run unencoded source material to establish a benchmark
2. Adjust the bitrate on the new encoder in steps (say 1 mpbs)
3. Measure the deterioration in picture quality at each bitrate level.
4. Select the bitrate that gives 1 or 2 levels of deterioration, no more than this

I can't see from Andy's blog where different bitrates where compared on the new encoder- or am I missing something?

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