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Just a question about distribution (January 2018)

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NG
noggin Founding member
Slightly unrelated but factual none the less, The Big Brother highlights shows are played out live from the MCR onsite just like a live show, presumably because they edit so close to TX time.

This isn't uncommon - quite a lot of short-turnaround sport reversions are played from EVS to TX because the file wouldn't make it to server on time.


Yes - and even if Playout offer a line recording facility there are often limits to the turnaround time. At one point I believe Red Bee wanted 3x duration of your show clear at the end of the line feed before the TX point. (So a 30 minutes show had to finish feeding 90 minutes before TX)

It's often easier to keep a skeleton crew on to TX a pre-record as a 'live play-in' as a result.
HA
harshy Founding member
I'd only compare transport streams (and the video decoded from them on the same platform and display) - anything else is adding too many variables.

I’ll try recording the Briefing from BBC World News HD and BBC News HD get it trimmed down so they are both exact length, the one thing I am expecting there is the BBC World News HD file to be larger then the BBC News HD one as the bitrate on BBC World News HD always hovers on the 8.3mbps mark.


Just to be clear I meant the visual quality of the bitstream - not the file size. Bitrate doesn't tell you the whole story unless you are comparing the same encoders with the same configurations (and running the same firmware)

Is the BBC News HD recording from DSat or DTT?

I was going to record the Astra 28.2e transmission and the 19.2e bbc World News hd recording of the same programme and see if there is anything visually different.
SI
simpfeld
Slightly unrelated but factual none the less, The Big Brother highlights shows are played out live from the MCR onsite just like a live show, presumably because they edit so close to TX time.

This isn't uncommon - quite a lot of short-turnaround sport reversions are played from EVS to TX because the file wouldn't make it to server on time.


Yes - and even if Playout offer a line recording facility there are often limits to the turnaround time. At one point I believe Red Bee wanted 3x duration of your show clear at the end of the line feed before the TX point. (So a 30 minutes show had to finish feeding 90 minutes before TX)

It's often easier to keep a skeleton crew on to TX a pre-record as a 'live play-in' as a result.


There is an interesting show about behind the scenes of Celebrity Big Brother. This is a link to it:

http://www.channel5.com/show/celebrity-big-brother-behind-the-scenes/

but seems down just now...
But on that it seemed to be the case that they played the recorded highlights show across in real time, but the commentary said it had to be delivered an 3 hours before (or something like that).

I'd have thought these days for a recorded show it would either be real time played out from the site or a file transfer. Not this i.e. playing out a recording in real time, for the other side to record in real time.

9 days later

HA
harshy Founding member
I’ll try recording the Briefing from BBC World News HD and BBC News HD get it trimmed down so they are both exact length, the one thing I am expecting there is the BBC World News HD file to be larger then the BBC News HD one as the bitrate on BBC World News HD always hovers on the 8.3mbps mark.


Just to be clear I meant the visual quality of the bitstream - not the file size. Bitrate doesn't tell you the whole story unless you are comparing the same encoders with the same configurations (and running the same firmware)

Is the BBC News HD recording from DSat or DTT?

I was going to record the Astra 28.2e transmission and the 19.2e bbc World News hd recording of the same programme and see if there is anything visually different.


I finally got round to it sorry, so a recording at 19.2e and 28.2e, i made an uncompressed capture at the precise frame from both channels and then put it together in this html document, simply hover over the image with your mouse and you should be able to see theres more detail in the BBC World News HD picture over the BBC News one, the one thing however i didnt expect was that the BBC World News capture has more colour then the BBC News one, this to me proves there is some filter used on the BBC UK channels that compresses the HD a little too much and whatever filter is being used is slightly reducing the colour too.

https://www.dropbox.com/s/670aoetk7oxael8/harshy.zip?dl=0
NG
noggin Founding member

Just to be clear I meant the visual quality of the bitstream - not the file size. Bitrate doesn't tell you the whole story unless you are comparing the same encoders with the same configurations (and running the same firmware)

Is the BBC News HD recording from DSat or DTT?

I was going to record the Astra 28.2e transmission and the 19.2e bbc World News hd recording of the same programme and see if there is anything visually different.


I finally got round to it sorry, so a recording at 19.2e and 28.2e, i made an uncompressed capture at the precise frame from both channels and then put it together in this html document, simply hover over the image with your mouse and you should be able to see theres more detail in the BBC World News HD picture over the BBC News one, the one thing however i didnt expect was that the BBC World News capture has more colour then the BBC News one, this to me proves there is some filter used on the BBC UK channels that compresses the HD a little too much and whatever filter is being used is slightly reducing the colour too.

https://www.dropbox.com/s/670aoetk7oxael8/harshy.zip?dl=0


There won't be a separate filter - it will be a function of the H264 encoders used in each chain. Saturation can be influenced by changes in luminance/chrominance compression as heavier compression will alter them differentially (which means the RGB result is different)

Afraid I won't be downloading a Word Doc - but if you want to upload separate PNGs ?
HA
harshy Founding member
Yeah sure I’ll reupload the two uncompressed pngs tonight Smile
HA
harshy Founding member
Hello noggin, here are the two uncompressed pngs for comparison

*

*
MY
MY83
You just happened to pick the one frame where the presenter looks completely stoned out of her skull...
HA
harshy Founding member
MY83 posted:
You just happened to pick the one frame where the presenter looks completely stoned out of her skull...

Well newsreading is a serious business and it’s better to capture a frame with many elements so it can be compared.
RK
Rkolsen
Could the better PQ on the World News feed be a result of it also being used to feed cable (and other MVPD) headends?
HA
harshy Founding member
Maybe, it is a channel that shares with Al Jazerra News English HD, it seems to be static at 8.3mbps maybe not enough bitrate for cable?
NG
noggin Founding member
Maybe, it is a channel that shares with Al Jazerra News English HD, it seems to be static at 8.3mbps maybe not enough bitrate for cable?


Would depend if the cable companies can remux without recoding I guess.

Will have a look at the PNGs in detail when I get a chance.

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