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Media Composer Shifts Audio Out of Sync: A Discussion

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Expanding tracks in Pro Tools was like the holy grail to us dialogue editors when it came along.  No more messing about with EDLs and basically having to rebuild the picture editor’s sound arrangement.  When conforming from EDLs, it could take you the best part of a week just to get your session to match what was in the corresponding OMF.  So, the possibility of simply ‘expanding’ a linked AAF to create a perfect copy of the Media Composer audio tracks but with all the separate mic channels reinstated as well was very exciting indeed.

Many a time it works perfectly, but too often the expand seems to work – all the mic channels appear – but there’ll be a fractional and inconsistent discrepancy in sync.  For a while, no-one (that I knew) could seem to figure out why Pro Tools does this – we humble sound editors tend to presume things like this must be our or our tools’ fault  :)

So then you have to either use Titan sync fix to correct the discrepancy (which is fine except for sections with no distinguishable transients for the program to recognise and match) or we have to correct the sync manually ourselves, which basically turns an exciting new feature into a creator of dull, laborious, time-wasting extra work.

This was the prospect facing a work colleague of mine a couple of weeks ago, so he asked me if I’d tweet to see if anybody had any better alternatives to Titan sync fix; it wasn’t working very well for him on this occasion so he was facing the distinct possibility of having to manually sync the session himself.  However, before I put the call out on Twitter, we had one last look at the different clips within the session and compared their original timestamps and suddenly the penny seemed to drop!  It’s the MXF files in the linked AAF that are out of sync, not the original WAV files on the tracks expanded from it – Pro Tools is correct, Media Composer is out – so all this time we’ve been ‘fixing sync’ but by matching the AAF or guide track we’ve actually been pulling our sound out of sync!!!  At least, this is my opinion…..

All is explained below in this almost verbatim (I’ve corrected ‘twitter speak’ in places to help clarity) transcript of the subsequent chat I had on Twitter with Davide Favargiotti in Rome and Doug Murray in the States.  As you’ll see, Davide and Doug are not totally convinced (neither is my work colleague) but to me it seems to be proven by the numbers involved.  Decide for yourselves; feel free to shoot holes in my argument if you can – I want my theory thoroughly road tested by you lot before the start of my next job!

 

MM:  Monday morning question for you all:  anyone got a clever alt solution to loose sync when expanding tracks in PT other than Titan sync fix?

DF: an intern to fix the sync? :)  What recorder did the mixer use? it could be an issue with the recorder.  Nagra and zaxcom have this problem.

MM: I wish! It was a Deva, so your theory is still intact.  :)

DF:  it’s a bug: devas and Nagra don’t close files on frame edges.  MC fill the missing audio – this means that pd and aaf media are different.  Your media could be out of sync +-1 frame.

MM: so if your theory is correct davide then our expanded tracks are actually in sync and the editor’s aaf is out?

DF: nope.  Did he use autosync in MC?  If not, the guide and AAF are in sync.  If he used auto sync, everything could be off.

MM: dunno yet but I presume auto sync is normally used?

DF: check it: take the same clip from AAF and PD.  Go to the end of both files.  The AAF has some ‘silent’ bits at the end?

MM: exactly, the front of the aaf file is snapped to nearest frame then the difference at the end is filled with silence.  Therefore, MC is manipulating orig audio & so isn’t true sync anymore?  The pic hasn’t undergone same shift in MC?

DF: you’re fucked, mate.  :)  it’s a good time to get yourself some apprentice or intern :)

MM:  :D it’s ok I’ve just used Titan fix sync this time but my argument I’m suggesting is did I really need to fix sync?  i.e. are my expanded tracks true sync & the MC AAF is fractionally out of sync?

DF: if the assistant editor manually synced the clip, inside MC everything is in sync. (And all the export too, aaf and gt).  (or better…They have the sync that the assistant editor choose).

MM: so we could test this by getting asst ed to manually sync a scene then check it against our expanded tracks.

DF: …If auto sync was used in MC could be slightly out of sync too.

MM: auto sync isn’t what alters the audio file though?  That just positions it, if audio file wasn’t altered pt would be the same

DF: nope.  Importing audio files into MC alters them, if they aren’t closed on frame edges.

MM: so the case I’m suggesting to you is pt expanded tracks linked to rushes are not out of sync as they & the pic have not been ‘altered’.

DF: the problem is that PT gets the TC from the AAF files.  So you’re relying on something that has frame accuracy at most.  Check this:

http://duc.avid.com/showthread.php?t=345993

MM: going through the duc thread thoroughly, so far I’m with mark franken

DF: So, what’s the correct sync?  PT expanded tracks?  but doesn’t PT get the TC from the AAF?

MM:  exactly, that’s my line of thought.  i.e. that the start position of audio in MC is shifted but it’s orig time stamp remains true, so when we expand tracks, rushes are true.  If this is correct, the pt expand would have to be agreed (with editor) as the main sync reference for sound.  I drew a pic to try to explain what I’m saying better.  Feel free to shoot holes in it if I’m missing something.

P0

DF: I’m not sure.  It could be.  You can’t know for sure how much the file has been moved ahead by MC

MM: True, I don’t know this for sure, but I do know MC is definitely altering the audio file and PT isn’t.  I know MC definitely isn’t absolutely sample accurate orig sync but PT might / could be.  @Avid, can you confirm if this is the case (…no response came…)

MM: Using info in Wave Agent to prove Pro Tools is in sync, and MC is out? See below:

P1

(Doug Murray gets involved in the chat at this stage)

MM: Do you agree that the PT expanded tracks are more accurate sync than the MC AAF, Doug?  & that therefore us dialogue editors shouldn’t be resyncing our expanded tracks to match an out of sync AAF?  Have we been following a false God all this time?  Are we actually the true Gods of Sync?!  :)  If so I’m looking forward to my ADR now being up to half a frame more accurate!

DF: I’m not convinced yet of this new god to worship. :)  I’d like to know where PT gets the pos ref to expand tracks.

MM: Don’t the orig time stamp diffs between the AAF & WAV file prove the WAV is correct?

DM: If the syncing is done in MC, then the AAF is most accurate.  If done elsewhere, then I don’t know.

MM: How so if MC is a frame accurate system dealing with sample accurate data?

DM: If syncing is done in MC with clapboard as the means, then AAF best.  If orig time stamp is means then pd best.

DF: yeah, this makes sense to me too…either case aaf and PT are never in sync (with devas and nagras)

MM: Are you saying if editor manually syncs in MC = AAF most accurate sync? & if he uses auto sync in MC = PD in PT most accurate?

DM: Yes.  That makes sense to me.  TC sample accurate on autosync but AAF sync ref most accurate even if only frame accurate on man.

MM:  Hmm, think I disagree – MC is only frame accurate either way?  I guess I’m saying I’d prefer auto sync as it changes the MXF timestamp relatively, enabling PT WAV to retain it’s true pos ref.  Manual sync doesn’t change the MXF orig timestamp (correct?) so PT WAV will move with it:  out of sync to nearest frame.  We feel safer that way coz our WAV now matches the AAF, but it (& the AAF) are now both fractionally out of sync.  This is all putting aside the additional ambiguities & potential for human error that are possible with manual sync.

DM: Does MC take the 1st whole frame of TC & call it the 1st frame? or the 1st partial frame? i.e. rest amp early or late?

MM: start of clip snaps to start of nearest frame but my understanding is the orig TC stamp stays intact relative to the timeline.  Hence why I believe the wav in PT with it’s unaltered orig time stamp retains it’s correct positioning on the timeline.

DM: Nearest?  I think it’s consistently early or late.  Can’t remember which.  MC def restamps code – which is cause of problem!

MM:  No I think my example in my 2nd pic I tweeted the other day proves MC snaps audio later too, whichever frame edge is nearest.  I agree  MC def restamps orig TC, but relatively, so I’m suggesting it’s a good thing for us rather than a problem as such.

 

So that was our discussion – my conclusion from all this is that, potentially, we (dialogue editors) shouldn’t be automatically resyncing to AAFs made in Media Composer.  Obviously if your audio is out of sync by a few seconds or more then you’ve got a different problem going on but I’d say if your working on a project shot on a Nagra or Deva and the sync is loose by no more than half a frame (early or late) when you expand tracks from an AAF made by Media Composer using autosync then it seems a pretty safe bet to me that the difference in sync is the alteration that Media Composer has made to the sound rushes when loaded in.  Media Composer is out of sync, not Pro Tools, so why follow that as true sync when it could be up to half a frame out of sync?

Please feel free to add your two cents – although I’m talking definitively here, I’m happy to admit I’m wrong if someone else can prove otherwise.  We need to get to the bottom of this problem once and for all!

 

About Time – Dialogue Editing Techniques

Screen Shot 2013-10-13 at 19.58.31

It’s been a while since I last posted about my dialogue editing techniques on a specific film so, with the release of the latest one I worked on, About Time, I thought I’d share some thoughts on a bit of software I experimented with on it -  a relatively new plugin called Unveil by Zynaptiq that I’m sure most of you have already heard of and / or had a play with.

It’s an impressive bit of software:  There are a few different ‘de-reverberation’ plugins available at the moment – the main ones that spring to mind are SPL’s De-Verb and iZotope’s new dereverb module in RX3 – but, in my humble opinion, Unveil is definitely the current frontrunner.

My intention is not to show you how to use it – google will offer up plenty of other sites which have already done that very well – rather, I thought it might be useful to provide a real working example of it’s accepted usage on a mainstream film.

It’s an interesting time for dialogue editing in terms of some of the blurring boundaries between what constitutes part of the editing process and what should be left for the dialogue premix in a dubbing theatre.  Until this point, I’d only made use of Unveil on short pieces of audio; for example, the end of a line that used a different, wider slate or one word where an actor happened to turn his head off mic for a second.  However, on ‘About Time’, one particular scene presented an opportunity to experiment with using it in a bolder manner.

The scene in question was shot in a cafe inside an echoey art gallery space.  The booms weren’t off mic but inevitably sounded rather reverberant, while the radios were bumpy and shashy so couldn’t be used very much for reinforcement.  Here’s where I got to with my final edit (this is just a short section of the scene):

Note, an example of the continually blurring boundary between editing and premixing:  Earlier in the year when I worked on this, I felt differently but if I was editing this scene now I would render a notch of the very clear whine that permeates through this scene.  I would always keep an untreated copy of the edit to hand just in case but with these very clear whines (that appear as an obvious solid line when viewed in a spectrogram) I don’t see the risk of a judicious editor doing the honours and saving a bit of time for the mixer in the theatre.

Anyway, as you can hear, the booms aren’t terrible but they seemed to lack a bit of focus that I was concerned might cause clarity problems once background FX and music were added in the mix.  Therefore, I decided I’d have a go at ‘de-verbing’ the whole scene and offering the result up as an option at the premix so the mixer could choose which he preferred.

So, definitely ‘drier’ but I would say that the reverb reduction does sound a bit unnatural in some ways when heard this exposed.  However, my idea was that this treated version would be given some ‘polish’ by a high end reverb at the premix.  This is exactly what happened; in effect, the reverb was put back on but now clarity and focus could be controlled depending on the type and quantity of it applied.  So, the end result, placed in the context of the final mix as a whole:

Although this de-verbed version of the scene ended up being preferred and used in the final mix on this occasion, this by no means opens the floodgates for me in terms of the regular use of deverberation on my dialogue editing on future films.  The important point to note here is that this exciting development in software technology simply gives us dialogue editors one more card up our sleeve in the pursuit of improving clarity and minimising ADR line counts.  Some of these cards are best played in the edit room, but sometimes they need to be saved for the theatre, to be decided upon in the context of the mix as a whole.  I feel that this is how we can be braver in our editing choices on occasions – as long as you can present an experiment, such as the one I’ve explained here, as a quick, clear and simple A/B comparison to your mixer at the premix then you’re not locking yourself into anything and can make an informed decision together in the big room.

From The Horse’s Mouth

d43755194fa0bd51cffe8667d11dd069adf74e50.620.350.1.0.617.349This weekend, I gave a very short talk at an event in Newcastle, called From The Horse’s Mouth.

It was organised by Tyneside Cinema as part of a short film course they’ve been running for 15-19 year olds in the North-East. The aim was to get a few industry professionals to talk a bit about how they found their way into the industry, with the hope that this might provide some useful advice to the course participants.

I’ll be honest, although I’m happy to give advice whenever asked, the main reason I agreed to talk was as a favour for the organiser, the filmmaker and writer, Ian Fenton, who I know and like from way back when I did the sound for his short film, Flickerman. However, in the end, I think Ian is the one who did me a favour: It was fantastic to get an opportunity to chat with the other speakers who had such diverse roles, like screenwriter, cinematographer, distributor and programmer. How often and how else would you get the opportunity to talk with such a cross-section of the industry?!  I strongly recommend taking up such an offer if you ever get the opportunity – I’m sure I got more out of it than I was able to give.

Anyway, I promised Ian I would post a kind of reading and links list as a resource for any of the participants, should they be interested, so I’ve added it below. Firstly, I thought it might be worth adding a rough transcript of my presentation too.

Fellow pros, please feel free to add any of your own recommended reading, links or advice in the comments section.

TRANSCRIPT OF MY PRESENTATION

How did you get from school to where you are now?

At school, I naturally gravitated towards the arts; particularly English and then, when I went to University in Manchester, I studied History of Art.  While I was at Manchester, I got very into the whole music & DJing / nightclub scene there.  By the time I’d graduated, I’d become interested in learning how to make my own music rather than just playing other people’s, so I signed up to a course at a place called Manchester Midi School which was basically an intro to music production and midi programming.  I absolutely loved it, and emerged from it, a year later, desparate to work in a recording studio.

This inevitably focused my sights on London where, over a period of about 2 years, I picked up dribs and drabs of work experience or very low-paid / unpaid work as a runner at various studios around London (the most significant stint I did was probably running at Livingston Studios when Ry Cooder was mixing Buena Vista Social Club there).  By chance, one opportunity that came my way at the end of that 2 years was a staff job as a runner at a post-production sound facility in Soho called Magmasters.  Unlike running in a music studio, which generally only offered occasional shifts which you were lucky to get 20 quid for, I started at Magmasters for the princely sum of £7500, which enabled me to move to London for the first time, albeit into what was basically a squat in Brixton!

From then on, it was just about hard graft, and trying to be amiable, diligent, humble or confident, depending on the situation.  I made teas for about a year and a half – all the time learning how to use the studios and their hardware.  As a result, I was able to fill in when a sound editor or recordist was off sick or left to work elsewhere.  From there, it just became about working hard to gain more experience, more responsibility and more opportunities.  I’ve done all sorts of post sound roles since then and now work at another, smaller post sound company called Phaze UK, where I now specialise in Dialogue and ADR Editing for films.

What is your role now?

My role as a Dialogue Editor is to firstly take all the location recordings that the Picture Editor has used in his/her cut and make these sound as smooth, fluid and ‘natural’ as possible, so that there are no jarring cuts or distracting bumps and bangs on the characters’ dialogue.  Any lines of dialogue that are unusable, due to noise, clarity or performance, have to be replaced with ‘ADR’ (Automated Dialogue Replacement) which is recorded in a studio with the actor/actress in front of a TV monitor, lipsyncing his/her original lines as they appear in the film.  Finally, I record additional background voices with a ‘Loop Group’ (this is called ‘Crowd ADR’) for any crowd scenes or to cover any spurious background people who can be seen to be talking behind the film’s principal characters.  Once all these stages are complete, I take all this work to a large dubbing theatre to be mixed in conditions intended to replicate how it will sound in a cinema.  My dialogues are mixed together with FX, Foley and Music to create the Final Mix in Surround Sound.

From your own personal experience, what are your 3 top tips for someone who wants to get into the film business? 

  1. Although I’d say a large proportion of people working in post sound are freelance, I would recommend starting off your career / getting your foot in the door via a staff job at a facility or small post soundhouse.  It’s simply a great way of being introduced to the trade, learning the trade and working out what aspect of the industry most interests you.
  2. Don’t chase positions at facilities or soundhouses by simply posting bucketloads of CVs.  I think this has always been a pretty futile endeavour but is particularly so since the internet and social media completely transformed how people connect and get each other’s attention.  Use these tools to create a platform where you show your passion, creativity and commitment.  Network and build relationships.  Get involved in groups, attend events – increase your chances of having a stroke of good luck come your way.
  3. Don’t just focus on learning the specific technical skills of the particular craft that interests you.  For example, with hindsight, I now feel that my English A-Level and History of Art Degree have served me just as well in the film industry as has my Diploma in Studio Recording.  This is because it is just as important to understand the art of storytelling as it is to understand the principles of sound.  Empathy, creativity and your analytical skills are as important as your technical ability.  One of the fascinating things about working on films is that you experience an eclectic variety of subject matter, so an open and enquiring mind is always useful.

RECOMMENDED READING

Dialogue Editing

Career / Attitude

WEBSITES OFFERING FILM SOUND CAREER ADVICE 

RANDOM / MISCELLANEOUS 

Google is such an amazing resource when it comes to researching, chasing leads, etc. – make full use of it!  A relatively short search whilst preparing my talk offered up this eclectic mix of articles, vids and websites that are relevant in a variety of different ways.  Don’t just look for advice from film industry pros – advice from any creative professional can be relevant to your own ambitions in the film industry.

iPad3 ♥ MixPre-D ♥ Auria

After much deliberation, I’m finally up and running with my iPad 3 / Sound Devices MixPre-D sound recording combo!  I only got about half an hour this evening to quickly give it a test run but I’ll share the resulting recordings with you as a rough demo:

My deliberation was due to originally wanting to use the Sound Devices USBPre2 but this setup was beginning to seem rather convoluted due to the USB Battery that would have been required.  I worked out the setup in the diagram below but I’m not 100% convinced it would have actually worked:

The ‘Dr. Bott’ Buss is (as I understand from what I’ve learnt from trawling the internet) simply a device to add into the chain in order to trick the iPad into not thinking the USBPre2 is too much of a power draw (which it isn’t) and rejecting it.  The Denecke is simply for taking the strain of the phantom power away from the iPad so that it’s battery would last longer.

I tweeted this picture a while ago and, after a few ideas and thoughts from others – namely Shaun Farley – Sound Devices themselves chipped in, suggesting I simplify things by using the MixPre-D which has it’s own built-in battery power supply.  Why didn’t I think of that?!  (Don’t answer that).

So now the only addition to the chain is simply the camera connection kit which enables the MixPre-D to link up with the iPad.

Initial tests have given promising results I think; good, clean sound like I’m used to hearing through the 744T.  I’ll do a more thorough variety of recordings over the next few weeks but tonight, unfortunately, I didn’t have a good stereo pair of mics to use recording some room tones, etc. so I’ve stuck with a quick voice record using my U87 and then some exterior train and siren sounds captured using my MKH40.  See what you think.

As for the actual operation of the setup, Auria is great!  If I can get everything packed up appropriately in some kind of bag with the iPad on top then I think I’m on to a winner.  As far as I’m aware, Auria is the first app to enable 96kHz recording on the iPad, which was my original stimulus for trying to achieve this recording setup.  Large meter display; a DAW at your fingertips; export AAFs to Dropbox – it’s hard to find fault really.  However, a couple of tiny bugs that I’ve come across so far:

  1. Listening through the headphones, I had to ‘reset’ this by unplugging and replugging the headphone jack a couple of times.  Once this was when I booted up Auria but wasn’t able to monitor the input until I replugged the headphone jack and then it kicked straight in.  The other time was when I was recording and tugged on the headphone cable too much and it seemed to upset the audio output from the iPad and introduce digital glitching noises until I replugged the headphone jack at which point the glitching stopped straight away (and wasn’t on the recording).  This is another reason to make sure that whatever bag I can get hold of to hold all this setup together has to protect all the USB connections and the headphone jack from any strain or knocks.  By the way, in my view, the most vulnerable connection to protect is the camera connection kit into the iPad (though I didn’t have any problems with it this evening); the USB connection into the MixPre-D feels really solid to me.
  2. A tiny detail which may perhaps be through my own error:  I did some editing in Auria before exporting the session to Dropbox and, strangely, the crossfades I did were carried through into Pro Tools but not the rest of the fades.  Will keep an eye on this next time.
  3. As far as I can tell so far, the settings in the iPad dictate the sampling rate of the recording and the MixPre-D follows suit.  However, when I connected the two devices and opened a 96kHz session in Auria, the MixPre-D continued to say it was set at the default setting of 48 kHz which was a bit unsettling.  However, judging by the final AAF that I opened in Pro Tools, the recordings are indeed 96kHz and 24 bit so surely the MixPre-D did tow the line with the iPad otherwise the recordings would have glitched?

So, after only a quick play this evening, those are my initial impressions.  I’ll keep you posted with any discoveries or bugs that I come across over the coming weeks, and Sound Collectors’ Club members can expect to see a lot more demos coming their way  in the  form of new contributions to various themes.  For starters, I’m planning to take this setup along to record church bells with Raoul in September.  Better get a move on with finding that bag……..

Skirt

As I’m sure many of you are aware, voting for the Vimeo Awards is currently in progress.  I recently discovered that a short film I worked on last year, ‘Skirt’, by the fantastic director, Amanda Boyle,  has been entered in the fashion category.  Please check it out and give it your vote!

Bar a few breaths and a couple of lines of Spanish, the film contains no dialogue but fully utilizes the foley services of the talented team at Park Road Post .  I took care of the background FX, for which I was able to plunder a few recordings from The Sound Collectors’ Club’s Night and Day and Trains: BGs themes.  Members spot them if you can!

UPDATE on 10/6/12:  Skirt won the fashion category!!!!

The Sound Collectors’ Club: Last Theme of 2011

So we’re finishing the year with what will hopefully be a variety of cafe atmoses from around the world.  Full details at: http://thesoundcollectorsclub.wordpress.com/2011/12/01/last-new-theme-of-2011/

Sound Collectors’ Club News

The latest theme:  ‘Protest’ is in progress over at The Sound Collectors’ Club.  For full info, head over to: http://thesoundcollectorsclub.wordpress.com/2011/11/01/new-theme-protest/

Also, the Night and Day collection is now back online – but not in the usual way;  The Sound Collectors’ Club may well move it’s stock from Soundcloud over to Sugarsync.  Check out the full details at:  http://thesoundcollectorsclub.wordpress.com/2011/11/22/night-and-day-reopens-right-on-your-desktop/

Dialogue Editing Videos by John Purcell

A few months back, I started off my series (all 2 of them!  One more to come soon….) of videos about dialogue editing techniques by saying that I didn’t think that dialogue editing was discussed much online – certainly not in comparison to sound design.

Consequently, when I do stumble across such information, as I did just the other day, I feel it’s only right that I do my bit to spread the word.

Apologies if most of you already know about these, but the other day I came across these videos of the man himself, whose book we all constantly refer to – John Purcell – talking a bit about dialogue editing.  I’ve only had a quick look but I thought I’d share them anyway; see what you think of them.

The Sound Collectors’ Club: September’s Theme

The companion collection to June’s theme is in progress over at The Sound Collectors’ Club!  For full info, head over to http://thesoundcollectorsclub.wordpress.com/2011/08/31/septembers-theme/ 

 

The Sound Collectors’ Club: August’s Theme

Quite a simple theme in progress this month over at The Sound Collectors’ Club, after quite a tricky one in July.  For full info, head over to http://thesoundcollectorsclub.wordpress.com/2011/08/02/augusts-theme/


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