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Audio synchronisation with RAW?

First of all I am so so sorry if this is posted in the wrong place. I am not sure where I should post this exactly? I just know that there are good people here that may possibly point me in the right direction. Again I apologise in advance.

I have now had several experiments trying to synchronise audio with the RAW video in post.

I am used to using the traditional method of recording audio on a external sound recorder (ZoomH2) and using a clapper board to get an audio/visual sync.

I have used this technique to get greatly improved sound when compared to the 5DMKII's inbuilt mic.

I have found it to be pretty reliable and with a visual cue (the clapper board) its pretty easy to align them in most decent NLE's

However I have tried aligning the separate audio with the RAW video and there is something that's not quite right.

A few days ago I just recorded some video with separate audio using clapper board and aligned them but in the video there was nothing else for me to see if the sync was staying in sync. I just made the assumption that everything was fine. Although I could never be sure exactly how good the sync was it just looked ok because all the sounds were happening off screen.

Anyway today I decide to test a little more thoroughly. I just set up a simple shot where I would use the clapper and then I would tap a little beat on a surface and obviously keep my fingers in the frame (so I could see if it was all in sync). I recorded a few takes of the same kind of thing with both RAW video being recorded and my ZoomH2 recording the sound.

I got them on the computer processed the RAW files and import them into After Effects. I then dropped the audio into After Effects and went in to align them. I aligned the sound of the clapper at the frame where the clapper shuts. This is something I have done numerous times before (with the old H264 video) and would usually be confident at this stage, that when I hit play everything will be perfectly (or very nearly perfectly) in sync.

Well this is not so. I am not sure whats happening. Where I have aligned the clap it's perfect but it seems that it must be drifting.

My only conclusion is that there is some mismatch somewhere in the timing of the two. The problem is where would that be?

One thing I would really like to know is that should the 23.976fps be processed as 24fps? (I have tried both and they both drift somehow).

In fact this one has really got me because I can't seem to get the sync whatever I do?

I am wondering maybe if I will have to do a slight pitch shift on the audio or maybe some kind of re-conform of the video. I don't want the additional processing involved but if I could somehow get some workflow that 'worked' then maybe that would help?

I must say at this stage I am lost with this one.

I was wondering if anyone else had any experience of audio synchronisation with the RAW footage?

Any help would be greatly appreciated.

Another RAW video 

http://www.youtube.com/watch?feature=player_detailpage&v=rPKnehmFdh0

I do apologise. More flowers

RAW Test - KomputerBay Professional 32GB 1000x CF UDMA7 - Part II

http://www.youtube.com/watch?feature=player_detailpage&v=RBt9nvER--o

I do apologise. More flowers

RAW Test - KomputerBay Professional 32GB 1000x CF UDMA7 - Part II

http://www.youtube.com/watch?feature=player_detailpage&v=RBt9nvER--o

How long are you able to record for in 1080?

I wasn't able to record in 1080 (I wish! maybe one day  )

1880x840

I rendered out the video 1:1 but in a 1920x1080 frame.

Even though I would obviously prefer 1920x1080 I like what I have at the moment the RAW makes so much difference. I love it!

Thanks again ML!

Today I finally got my KomputerBay Professional 32GB 1000x CF UDMA7 so I tested it ...

1880x840 is about the best I can get.

http://www.youtube.com/watch?feature=player_detailpage&v=Pf9iib286Vs

Today I finally got my KomputerBay Professional 32GB 1000x CF UDMA7 so I tested it ... 

http://www.youtube.com/watch?feature=player_detailpage&v=Pf9iib286Vs

Told you I had the flowers covered  ...

http://www.youtube.com/watch?v=oXle_MnR8OU

I am lazy. Next time I will do the flowers

Its OK I have the flowers covered

OK a better rendered version of my previous YouTube 5DMKII RAW test upload:

YouTube here:

http://www.youtube.com/watch?v=u47aj1h0m6k&list=PLWUV9WfHlRNNBbQ98y3J99YbxWiK-AMSq&feature=player_detailpage

and for the actual file here at mega:

https://mega.co.nz/#!Ut0mxSzJ!ZfuzVXUykfAmarhxQXZqhCRUagFTVBbZFbxwlDE-wsE

While its funny that they are getting H264'd again its much better to start with a non 8 bit image when post processing.

Clients may not need raw but they may need corrections that would fall apart at 8bit... if any of your clients need chroma key and you have to do it in 8 bit 

Totally agree!!! still funny 

Just chuckled to myself. Uploading these lovely RAW videos to YouTube is like sending it back through the 5D h264 algorithm!!!

(actually it probably is h264 compression anyway!?!)

But its still funny getting the very best quality footage to essentially degrade it to bits

These are my little tests. The very short edits are because this is how long I can record at 1880x720. You may also notice some jumping too. Of course this is far from perfect.

http://www.youtube.com/watch?feature=player_detailpage&v=p9uZXUGDJSA

Recorded on the 5DMKII with DURACELL Pro Photo 600x UDMA 16GB CF card. I think the build I was using was the one from the 13th?

I have ordered a Komputerbay 1000x 32Gb and am hoping that it will improve the situation (reading the posts on here I am glad I chose the 32Gb one instead of the 128Gb)

are you referring to the "bit depth visualization"? That "12 bit" image shows a 4 bit per channel bit depth and we're talking about 12 bit/channel here ;-)

Not following you there?

The images (*.dng) files that are being discussed on this forum are 14-bit (apparently). I posted the link to the Cambridge in Colour site just as a good reference to explain bit depth. It makes it pretty clear (at least to me) about the differences in bit depth. I posted the link purely as an information source. I think that such a site is a good resource as regards to digital photography. Some of the fundamental stuff is important for reference (in my opinion anyway)

Hey there
this question has probably already been asked, but whats the great advantage of 14 bit vs. 12 bit RAW recording? If people have problems with 1080p on some cards but get it working nicely with 900p, why can't you just reduce the bitsize and therefore storage / datarate requirements? Sure 14 bit give more colors to work with but I can't imagine any situation where 12 bit is not enough. Am I missing something?

Take a look at this ...

http://www.cambridgeincolour.com/tutorials/bit-depth.htm

I wasn't able to record 1920 x 1080, with earlier builds the buffer kept filling up but doing some testing today with the May 14th build it seemed to sort it out. I didn't stress it out with leave's or trees or anything like that but the frame were busy and it handled it well till i hit the 4Gb limit.

Are you running the latest build?

I want to draw attention to something here. You talk about 'stressing stuff out'. You need to think of RAW as a whole different beast (from compressed formats such as h264). With RAW a 'frame' will always be exactly the same size(in Mb). This means that a highly detailed image will contain exactly the same amount of data as a low detail image (even a blank frame) There is NO compression going on at all so there is no 'stressing'. Whereas compression based formats (h264) vary in size (and of course quality). This is why there is a variability with the image sizes of files in h264.

Just to clarify this you might want to check the file sizes of your RAW (*.dng) frames. You will find that they are always the same size(of course dependent on the resolution). This is the double edged sword that is RAW. On the one hand it has the absolute best quality at the expensive of being so space hungry (I mean in MB/s). Once you can deal with the data rate you should be fine. In simple terms the data requirements are a constant.

Double buffering seems to have fixed 5d2:

Frame dropping starts about 18 seconds in and continues for the rest of the video (as expected)

I am really interested to see 5DMKII stuff and this is some of the first I have seen. I would like to try the build you are using (maybe you could link me to your build?).

Anyway its encouraging footage and I was wondering what CF card you have and write speed you are achieving?

Please people quote numbers!

Keep it up good people. YAY!!

It's very good too see example videos appearing on here. What I am thinking is that it would be nice to see the original compiled videos (as in before YouTube without the YouTube compression ).

Maybe someone (or people) could use a file hosting place like mega (https://mega.co.nz/)  to host the files and link them here?

I would especially like to see what 5DMKII as capable of here.

I congratulate the good work and am willing to test on 600x (Duracell) CF card on the 5DMKII if someone could provide me with a build(?)