2 questions about Sequence Settings: Starting Timecode & Editing Timebase

[Juan Todoli]

Just swimming into the Sequence Settings I notice 2 details that I don't have too much clear.


a)

Why Starting Timecode (in Seq. Settings/Timeline Options) starts at 01:00:00:00 by default? I'm missing out something or I'm wrong (by logic) that, in general, any sequence starts at cero time? What does this 01 means?


b)

Why previously configured my custom easy setup and having choosen the Sequence & Capture Presets in the A/V Settings both in 24 fps, I have no notice about this exactly 24 number nor in the easy setup neither in the editing timebase pop up menu at the Sequence Settings/General/Editing Timebase? Always appears 23,98 in all menus I open and have to change manually. Did I forget something?


Thanks in advance.

[Juan Todoli]

Forgot to expose my workflow:

Simply Capture in HDV and transcode to Prores 422 to authoring for web in HD 720p.

I do not work whit any PAL or NTSC systems (refering to the problem about the 23,98 fps, if applicable witn down-converting issues).

Thanks.

[Devin Termini]

It doesn't really matter if the sequence time code starts at 1 hour. You can change it so that it starts at zero if you like.

It has been done this way in the past so that post houses and production companies can set up their VTR's to record beginning at 1 hour. Actually they would program them to start at 59 minutes then lay in black, color bars, slate, and countdown. Then they would be ready for the first frame of video to drop at exactly 1 hour.

Delivering to the web makes this a useless feature.

With regard to your 23.98 issue - there very few cameras that actually record at 24fps. Since you're recording on HDV, you don't have one of these cameras. Your frame rate is 23.98.

[Juan Todoli]

Thank you for the explanation Devin. Perfectly understood.


And regarding the 24p recording mode, cam's manual in his main features says:

"720/24p shooting function ussing the 2:3:2:3 pulldown".

My camera is a JVC GY HD110E


Then the pulldown generate 23,98 instead 24?


Thanks again.

[Andy Mees]

a) Why Starting Timecode (in Seq. Settings/Timeline Options) starts at 01:00:00:00 by default? I'm missing out something or I'm wrong (by logic) that, in general, any sequence starts at cero time? What does this 01 means?

Remember that traditional tape based systems require cueing and the trouble with having any programme start time at 00:00:00:00 is that any such cueing could confuse the tape transport system eg if the tape is rewound just 1 sec before a zero programme start then the apparent timecode value would appear be 23:59:59:00 and hence the transport system would think it needs to rewind the tape a further 23 hours 59 minutes and 59 seconds to find zero (whereas in this example the actual programme start is just 1 second forward of the cue point).

For this reason, programme start times are never traditionally set at 00:00:00:00 ... and fwiw 01:00:00:00 is simply the nominal timecode traditionally preferred and used for programme start time in the US market (for tape based video content).


b) Why previously configured my custom easy setup and having choosen the Sequence & Capture Presets in the A/V Settings both in 24 fps, I have no notice about this exactly 24 number nor in the easy setup neither in the editing timebase pop up menu at the Sequence Settings/General/Editing Timebase? Always appears 23,98 in all menus I open and have to change manually. Did I forget something?

Tricky. Although time bases are often referred to as "24" fps and "30" fps the actual time bases in those instances are (approx) 23.98 fps and 27.97 fps respectively. This is due to the dropframe mechanism used in NTSC systems to compensate within timecode for the carriage of color information in a signal originally designed for black and white transmission. Hmmm .. search for "dropframe" and "SMPTE" for more accurate descriptions of what is going on.


Hope it helps
Andy

[Juan Todoli]

Thanks very much about the "cueing" explanation. Perfectly understood.


But...

Originally Posted by Andy Mees

Although time bases are often referred to as "24" fps and "30" fps the actual time bases in those instances are (approx) 23.98 fps and 27.97 fps respectively. This is due to the dropframe mechanism used in NTSC systems to compensate within timecode for the carriage of color information in a signal originally designed for black and white transmission.

Yes, I knew about it.

As I exposed, I do not work with any intermediate NTSC system any moment or similar to "transcode" or adapt my footage in this sense. I produce in 24p (if my camera really support this "pure", still don't certain know as you has noticed about HDV), edit in a 24p timeline & delivery directly to the web in 24p.

That's my doubt about ussing 23,98 in any moment taking in acount my simple workflow.

Thanks very much for you help.

[Perrone Ford]

Your camera does not shoot true 24fps. It shoots 23.976.

Simple.

[Juan Todoli]

Lessons learnt.

Thanks guys.