Adam Garstone
Getting past the Geeks
Amazingly, life as a professional editor is not all red carpets and lunch with Charlize Theron. Sometimes we have to do some work and show that, not only are we gifted and beautiful, but that we also know stuff. Sadly, one of the best ways of showing that you don’t know stuff is for your latest prime-time, hit TV programme to fail tech review. People tend to shout at you too as, for some reason known only to the scheduling departments of major broadcasters, tech reviews happen about seven seconds before the programme is supposed to air and, gifted and beautiful though you are, you are unlikely to be able to fix the problems in time.
Of course you need to check for the obvious things – missing clips, timeline gaps leading to black flashes, badly rendered graphics and so on, but technical reviews dig a little deeper than that.
Photosensitive Epilepsy
One of the most common reasons why programmes are rejected is that they fail the Harding test. This is actually a series of tests, named after Professor Graham Harding from Aston University, that look for video that may trigger photosensitive epilepsy in a viewer. It’s a big topic, but to be safe look for anything that might flash in your sequence, like flash photography, explosions or just rapid edits. If the flashes are nine frames or more (at 25fps) apart you don’t need to worry about their intensity or how much screen area they cover or how red they are and so on - they should be safe. Some badly anti-aliased CGI can product 25Hz inter-line flicker (particularly horizontal lines) which can be another cause of failure. Epilepsy can also be triggered by repeated bars of light – generally five or more – especially if they move or flash. This can happen even if the bars are made of other elements, like polka dots. Interestingly, a close-up of the flag of the United States of America can, reputedly, cause some people to have a seizure. If there’s a joke in there, I’ll leave it to you to devise.
If you are interested in more details, check out:
http://www.ofcom.org.uk/consult/condocs/Broadcasting_code/broadcasting_code/annex8/#content
Video Levels and Gamut
I’m sure you are all familiar with FCP’s Scopes – they can be found in Tools->Video Scopes (or press Alt 9). Because I am old and remember when these things were real cathode ray tubes, I prefer the display in green – right (or ctrl) click on one of the scopes and select Green from the contextual menu. As you are grading in FCP, make sure you keep an eye on the scopes as your programme will fail tech review if luma (waveform monitor) strays outside the range -1% to 103% and chroma (vectorscope) exceeds 105%.
It can be useful to turn on the Canvas Range Checking too – select the Canvas window and go to View->Range Check->Both in the menus. A green tick in the Canvas window means all is well, a yellow exclamation triangle means danger (though you might still be broadcast safe – check those scopes – as there is no way to adjust the sensitivity of the Range Checking display to our broadcast standard).
Final Cut is shipped with a Broadcast Safe filter (Effects->Video Filters->Color Correction->Broadcast Safe or select it from the Effects tab in the Browser). Like most video legalisers it just clamps video outside a preset range (though it does try to have a soft knee) so can do nasty things to your highlights and colour saturation. Imagine the effect of washing your favourite Ted Baker shirt in Domestos – I wouldn’t recommend it, but it can be a handy safety precaution if you are in a hurry (the Broadcast Safe Filter – not Domestos). The ‘Normal’ preset should do the job.
Aspect Ratio
Aspect ratio seems obvious - most prime-time TV is now commissioned in 16:9 Full Height Anamorphic (FHA). Letterboxing 16:9 in a 4:3 frame is unacceptable as many TVs recognise the black bars and zoom the image, annoying the viewer and undermining the artistic intent of the programme. You can also get into problems mixing 16:9 and 4:3 (archive footage, for instance) – most commissioners insist that you zoom up the 4:3 archive, effectively making a 16:9 window on the 4:3 footage, rather than having sidebars. Where you really need to pay attention is with Safe Areas. For most 16:9 TV in the UK, safe areas must be set for 14:9. Sport programming, and most Americans, insist on 16:9 programmes having 4:3 safe areas. Unfortunately, the safe areas shown by selecting View->Show Title Safe from FCP’s menus don’t comply to the EBU specification though, being American, they do show 4:3 ticks on 16:9 sequences. If you want to get it right, there is a plug-in from Digital Heaven called DH_WideSafe that does the job, with correct action and title safe areas and a nice interface. Go to www.digital-heaven.co.uk/dh_widesafe.
Audio levels
Another slight problem with FCP is its audio meters. Actually, thinking about it, it’s not really FCP’s fault. Before digital audio arrived, broadcasters like the BBC were used to using Peak Programme Meters (PPMs). These had ballistics that allowed for analog transmission characteristics – if an audio signal overmodulated for a short time, you couldn’t hear the effect and so a PPM allows for it. Then the world turned digital – an overmodulated signal (i.e. greater than 0dBFS) sounds horrible, but the BBC had lots of PPMs kicking around that they couldn’t afford to throw away, even though a peak meter like FCP’s makes more sense with a digital signal.
So they came up with a way of relating their old PPMs to the digital signal that allowed for some headroom. A continuous tone at -18dBFS on FCP’s meter will read PPM 4 on the BBC’s meters. This is the nominal mix level for your programme (and the line-up tone level that we use on the videotape we send to the broadcaster). That same, continuous tone at -10dbFS will read PPM 6. This is the maximum level for your audio. Unfortunately for FCP, real audio is more complicated than tones. If you mix using FCP’s meters – keeping a nominal -18dBFS and no excursions above -10dBFS – your programme will probably be too ‘quiet’ on the broadcasters PPMs. The peaks in the audio that you see so well on FCP’s meters are missed by the PPM, making you overestimate the levels.
Sadly, that means you need an EBU/BBC PPM to mix audio, accurately, for broadcast, and FCP doesn’t come with one. Fortunately, there are a couple of third party solutions that fit the bill – though they are a bit fiddly to use.
Audiofile Engineering (www.audiofile-engineering.com) make a fantastic product called Spectre. It contains a host of different audio meters, including BBC PPMs, which will work with FCP and Logic, though not Soundtrack Pro. It costs US$79 and is available directly from their website. There is a similar product called PPMulator+ from Raw Materials Software (now distributed by Z-Plane – http://products.zplane.de) which costs £75.41. I find Spectre easier to use with FCP.
You’ll need to route the audio output from FCP to your meter. Download and install the free application Soundflower from http://soundflower.googlecode.com/files/Soundflower-1.5.1.dmg. This excellent application gives you a virtual input and output inside your Mac, so you can now launch FCP and set the audio to output through Soundflower (2ch) by selecting it from the FCP menu View->Audio Playback. From Spectre->Preferences… set the input to Soundflower (2ch) and the output to your normal audio output device. You have now inserted the Spectre meter between FCP and the Mac’s outputs. The only downside of Spectre is that there isn’t an “Always on Top” setting for the meter window, so you’ll need to clear some screen real estate for it. Remember, mix to a nominal PPM4 and don’t let your audio stray above PPM6. The most common viewer complaint in TV is not being able to hear dialogue so don’t drown your ‘talent’ in music and effects. If they are particularly annoying, use a swimming pool or a well filled bath.
Line up signals, Bars and tone, Clock
By convention, programmes always start at timecode 10:00:00:00, mostly because timecode can’t cope with midnight, so it’s best to keep well clear of it. Before the programme we need some line up signals and programme identification, as follows:
The clock must be circular in the appropriate aspect ratio. To a certain extent, these leader requirements and the Ident will vary from commission to commission – Sky, for instance, like 100% bars. The Ident usually contains at least the Programme Title, a unique identifying number, the aspect ratio and some contact details.
Note that, once again, the leader in Final Cut’s File->Print to Video… just doesn’t cut it. You’ll need to use Effects->Video Generators->Bars and Tone->Bars and Tone (PAL Full Frame) or More Bars and Signals. The tone in the Bars and Tone generator is at -12dBFS, so don’t forget to change the level to -18dBFS. Similarly, FCP’s clock is no good, so you’ll need to source a better one – if you are preparing material for a broadcaster, they’ll probably have one they can give you.
The programme audio should fade in and out gracefully and there should be a freeze frame (often the last ‘page’ of the credits) or a ‘living hold’ for 10 seconds. If the Programme is an insert into a live show, you’ll usually need 2 seconds of video at the start of the programme, without cuts and before any dialogue or other important audio starts. That gives the live vision mixer enough time to roll the tape (or playout server) and cross fade to your material. For SD, most broadcasters expect your delivery format to be Digi Beta.
Technical Review for HD TV
HD technical requirements are mostly the same as SD with a few fairly obvious additions:
Most HD broadcasters allow you 10-25% of non-HD material in your HD programme. Interestingly, standard definition, for them, includes HD captured on lower end cameras such as anything HDV, any camera with a sensor smaller than ½”, Super 16mm film, NLE CODECs with bit rates below 160Mbps, and anything that can’t do 1080i/p except the Panasonic VariCam which gets special dispensation, for some reason. Frame based recording formats under 100Mbps and intra-frame formats below 50Mbps are also considered SD.
Personally, I doubt that these restrictions will outweigh budget constraints, in the long run (though we are stuck with them at the moment). When DV was launched, these same broadcasters announced that it wasn’t broadcast quality and no programme originated on DV would be acceptable. They now have entire departments set up solely to lend DV cameras to productions in order to keep filming costs down.
Obviously, your HD programme may well need a 5.1 audio mix. The delivered format should have stereo on channels 1 and 2, as with SD, with the 5.1 encoded using Dolby E on tracks 3 and 4. Encoded tracks should be:
Track 1 : Left front
Track 2 : Right front
Track 3: Centre
Track 4 : LFE
Track 5: Left surround
Track 6: Right surround
Tracks 7 and 8 aren’t used.
There is a lot of talk about the processing delays with Dolby E, and whether your audio should be delayed or advanced to cope with this – don’t do it. The audio on the delivery tape should be in sync with the video – it’s up to the broadcaster to make sure that they cope with the decoding delays when they play the tape out. Of course, FCP doesn’t encode Dolby E, and the encoders are really expensive, so you’ll need to talk to whomever does your playout about how they would like the audio delivered. Your final delivery tape is usually HDCam SR.
There was a time when no-one liked geeks. They wore funny glasses and corduroy and school children poked them with sticks. Sharp sticks.
Geeks, of course, now run the world and geekdom is the new rock and roll (my IT manager says). So all this technical stuff may seem a little dull in comparison to Charlize Theron, but the geeks are the gatekeepers and they will fail your programme if you don’t stick to their rules.
Of course you need to check for the obvious things – missing clips, timeline gaps leading to black flashes, badly rendered graphics and so on, but technical reviews dig a little deeper than that.
Photosensitive Epilepsy
One of the most common reasons why programmes are rejected is that they fail the Harding test. This is actually a series of tests, named after Professor Graham Harding from Aston University, that look for video that may trigger photosensitive epilepsy in a viewer. It’s a big topic, but to be safe look for anything that might flash in your sequence, like flash photography, explosions or just rapid edits. If the flashes are nine frames or more (at 25fps) apart you don’t need to worry about their intensity or how much screen area they cover or how red they are and so on - they should be safe. Some badly anti-aliased CGI can product 25Hz inter-line flicker (particularly horizontal lines) which can be another cause of failure. Epilepsy can also be triggered by repeated bars of light – generally five or more – especially if they move or flash. This can happen even if the bars are made of other elements, like polka dots. Interestingly, a close-up of the flag of the United States of America can, reputedly, cause some people to have a seizure. If there’s a joke in there, I’ll leave it to you to devise.
If you are interested in more details, check out:
http://www.ofcom.org.uk/consult/condocs/Broadcasting_code/broadcasting_code/annex8/#content
Video Levels and Gamut
I’m sure you are all familiar with FCP’s Scopes – they can be found in Tools->Video Scopes (or press Alt 9). Because I am old and remember when these things were real cathode ray tubes, I prefer the display in green – right (or ctrl) click on one of the scopes and select Green from the contextual menu. As you are grading in FCP, make sure you keep an eye on the scopes as your programme will fail tech review if luma (waveform monitor) strays outside the range -1% to 103% and chroma (vectorscope) exceeds 105%.
It can be useful to turn on the Canvas Range Checking too – select the Canvas window and go to View->Range Check->Both in the menus. A green tick in the Canvas window means all is well, a yellow exclamation triangle means danger (though you might still be broadcast safe – check those scopes – as there is no way to adjust the sensitivity of the Range Checking display to our broadcast standard).
Final Cut is shipped with a Broadcast Safe filter (Effects->Video Filters->Color Correction->Broadcast Safe or select it from the Effects tab in the Browser). Like most video legalisers it just clamps video outside a preset range (though it does try to have a soft knee) so can do nasty things to your highlights and colour saturation. Imagine the effect of washing your favourite Ted Baker shirt in Domestos – I wouldn’t recommend it, but it can be a handy safety precaution if you are in a hurry (the Broadcast Safe Filter – not Domestos). The ‘Normal’ preset should do the job.
Aspect Ratio
Aspect ratio seems obvious - most prime-time TV is now commissioned in 16:9 Full Height Anamorphic (FHA). Letterboxing 16:9 in a 4:3 frame is unacceptable as many TVs recognise the black bars and zoom the image, annoying the viewer and undermining the artistic intent of the programme. You can also get into problems mixing 16:9 and 4:3 (archive footage, for instance) – most commissioners insist that you zoom up the 4:3 archive, effectively making a 16:9 window on the 4:3 footage, rather than having sidebars. Where you really need to pay attention is with Safe Areas. For most 16:9 TV in the UK, safe areas must be set for 14:9. Sport programming, and most Americans, insist on 16:9 programmes having 4:3 safe areas. Unfortunately, the safe areas shown by selecting View->Show Title Safe from FCP’s menus don’t comply to the EBU specification though, being American, they do show 4:3 ticks on 16:9 sequences. If you want to get it right, there is a plug-in from Digital Heaven called DH_WideSafe that does the job, with correct action and title safe areas and a nice interface. Go to www.digital-heaven.co.uk/dh_widesafe.
Audio levels
Another slight problem with FCP is its audio meters. Actually, thinking about it, it’s not really FCP’s fault. Before digital audio arrived, broadcasters like the BBC were used to using Peak Programme Meters (PPMs). These had ballistics that allowed for analog transmission characteristics – if an audio signal overmodulated for a short time, you couldn’t hear the effect and so a PPM allows for it. Then the world turned digital – an overmodulated signal (i.e. greater than 0dBFS) sounds horrible, but the BBC had lots of PPMs kicking around that they couldn’t afford to throw away, even though a peak meter like FCP’s makes more sense with a digital signal.
So they came up with a way of relating their old PPMs to the digital signal that allowed for some headroom. A continuous tone at -18dBFS on FCP’s meter will read PPM 4 on the BBC’s meters. This is the nominal mix level for your programme (and the line-up tone level that we use on the videotape we send to the broadcaster). That same, continuous tone at -10dbFS will read PPM 6. This is the maximum level for your audio. Unfortunately for FCP, real audio is more complicated than tones. If you mix using FCP’s meters – keeping a nominal -18dBFS and no excursions above -10dBFS – your programme will probably be too ‘quiet’ on the broadcasters PPMs. The peaks in the audio that you see so well on FCP’s meters are missed by the PPM, making you overestimate the levels.
Sadly, that means you need an EBU/BBC PPM to mix audio, accurately, for broadcast, and FCP doesn’t come with one. Fortunately, there are a couple of third party solutions that fit the bill – though they are a bit fiddly to use.
Audiofile Engineering (www.audiofile-engineering.com) make a fantastic product called Spectre. It contains a host of different audio meters, including BBC PPMs, which will work with FCP and Logic, though not Soundtrack Pro. It costs US$79 and is available directly from their website. There is a similar product called PPMulator+ from Raw Materials Software (now distributed by Z-Plane – http://products.zplane.de) which costs £75.41. I find Spectre easier to use with FCP.
You’ll need to route the audio output from FCP to your meter. Download and install the free application Soundflower from http://soundflower.googlecode.com/files/Soundflower-1.5.1.dmg. This excellent application gives you a virtual input and output inside your Mac, so you can now launch FCP and set the audio to output through Soundflower (2ch) by selecting it from the FCP menu View->Audio Playback. From Spectre->Preferences… set the input to Soundflower (2ch) and the output to your normal audio output device. You have now inserted the Spectre meter between FCP and the Mac’s outputs. The only downside of Spectre is that there isn’t an “Always on Top” setting for the meter window, so you’ll need to clear some screen real estate for it. Remember, mix to a nominal PPM4 and don’t let your audio stray above PPM6. The most common viewer complaint in TV is not being able to hear dialogue so don’t drown your ‘talent’ in music and effects. If they are particularly annoying, use a swimming pool or a well filled bath.
Line up signals, Bars and tone, Clock
By convention, programmes always start at timecode 10:00:00:00, mostly because timecode can’t cope with midnight, so it’s best to keep well clear of it. Before the programme we need some line up signals and programme identification, as follows:
| Timecode | Picture | Sound |
| 09:58:00:00 | EBU 75% or 100% bars | 1kHz stereo tone -18dBFS (PPM4) 48kHz sample rate |
| 09:59:30:00 | Clock and Ident | Optional step tone |
| 09:59:50:00 | Clock and Ident | Silence |
| 09:59:57:00 | Black | Silence |
| 10:00:00:00 | Programme picture | Programme audio (48kHz) |
The clock must be circular in the appropriate aspect ratio. To a certain extent, these leader requirements and the Ident will vary from commission to commission – Sky, for instance, like 100% bars. The Ident usually contains at least the Programme Title, a unique identifying number, the aspect ratio and some contact details.
Note that, once again, the leader in Final Cut’s File->Print to Video… just doesn’t cut it. You’ll need to use Effects->Video Generators->Bars and Tone->Bars and Tone (PAL Full Frame) or More Bars and Signals. The tone in the Bars and Tone generator is at -12dBFS, so don’t forget to change the level to -18dBFS. Similarly, FCP’s clock is no good, so you’ll need to source a better one – if you are preparing material for a broadcaster, they’ll probably have one they can give you.
The programme audio should fade in and out gracefully and there should be a freeze frame (often the last ‘page’ of the credits) or a ‘living hold’ for 10 seconds. If the Programme is an insert into a live show, you’ll usually need 2 seconds of video at the start of the programme, without cuts and before any dialogue or other important audio starts. That gives the live vision mixer enough time to roll the tape (or playout server) and cross fade to your material. For SD, most broadcasters expect your delivery format to be Digi Beta.
Technical Review for HD TV
HD technical requirements are mostly the same as SD with a few fairly obvious additions:
Most HD broadcasters allow you 10-25% of non-HD material in your HD programme. Interestingly, standard definition, for them, includes HD captured on lower end cameras such as anything HDV, any camera with a sensor smaller than ½”, Super 16mm film, NLE CODECs with bit rates below 160Mbps, and anything that can’t do 1080i/p except the Panasonic VariCam which gets special dispensation, for some reason. Frame based recording formats under 100Mbps and intra-frame formats below 50Mbps are also considered SD.
Personally, I doubt that these restrictions will outweigh budget constraints, in the long run (though we are stuck with them at the moment). When DV was launched, these same broadcasters announced that it wasn’t broadcast quality and no programme originated on DV would be acceptable. They now have entire departments set up solely to lend DV cameras to productions in order to keep filming costs down.
Obviously, your HD programme may well need a 5.1 audio mix. The delivered format should have stereo on channels 1 and 2, as with SD, with the 5.1 encoded using Dolby E on tracks 3 and 4. Encoded tracks should be:
Track 1 : Left front
Track 2 : Right front
Track 3: Centre
Track 4 : LFE
Track 5: Left surround
Track 6: Right surround
Tracks 7 and 8 aren’t used.
There is a lot of talk about the processing delays with Dolby E, and whether your audio should be delayed or advanced to cope with this – don’t do it. The audio on the delivery tape should be in sync with the video – it’s up to the broadcaster to make sure that they cope with the decoding delays when they play the tape out. Of course, FCP doesn’t encode Dolby E, and the encoders are really expensive, so you’ll need to talk to whomever does your playout about how they would like the audio delivered. Your final delivery tape is usually HDCam SR.
There was a time when no-one liked geeks. They wore funny glasses and corduroy and school children poked them with sticks. Sharp sticks.
Geeks, of course, now run the world and geekdom is the new rock and roll (my IT manager says). So all this technical stuff may seem a little dull in comparison to Charlize Theron, but the geeks are the gatekeepers and they will fail your programme if you don’t stick to their rules.
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