search

ebu / ear-production-suite

The EAR Production Suite is a set of VST® plugins and tools for producing immersive and personalizable audio content suitable for any Next Generation Audio codec. It is based on the Audio Definition Model (ITU-R BS.2076) and the ITU ADM Renderer (ITU-R BS.2127) and enables monitoring on any ITU-R BS.2051 loudspeaker configuration.
https://ear-production-suite.ebu.io/
GNU General Public License v3.0
102 stars 20 forks source link

ADM BWF export to provide timecode reference #39

Open rsjbailey opened 3 years ago

rsjbailey commented 3 years ago

Chris Pike:

In a broadcast workflow, insertion of timecode reference into the exported ADM BWF file would be very helpful. The BWF BEXT chunk has a TimeReference parameter (https://tech.ebu.ch/docs/tech/tech3285.pdf). The start time in audioObjects should probably also reflect this.

Tom Nixon:

An alternative would be to represent this in the ADM (with the audioProgramme start time). This approach is recommended by BS.2088 (bw64), which says that the BEXT chunk shouldn't be used. There's some more information about how this should work in BS.2388 (ADM usage guidelines) too.

I'm not sure if this is implemented anywhere? Perhaps it should be a user choice.

Chris Pike:

I was hoping you'd know more :) Whilst 2088 says the BEXT chunk shouldn't be used, it might be that implementations expect it. So user choice is worth considering. I guess we should investigate how this info will be used, and by what, before implementing.

Richard Bailey:

Is this use case where a multitrack has been recorded during an OB using Reaper, and we're directly exporting from that session to an ADM?

How would timecode be used in this context as I'm a bit hazy.

Do you just record LTC to a spare audio track so you can line things up at a later date, or do you actually sync reaper to incoming timecode via the play button right click menu?

If it's the latter, how does that work in terms of timeline offsets (i.e. if you start recording at +2 hours is there a lot of empty space at the start of the session?)

LTC looks pretty straightforward so if it's already being recorded we could probably just directly decode it from some user-specified track on export (don't hold me to that :))

Simon Highfield:

Currently the use case is this: LTC is received on a MADI input The reaper timeline ‘chases’ (follows) the timecode input. When audio is recorded, it is ‘time stamped’. I believe this means that the time code that recording started at, is embedded in the BWF metadata. The LTC does not need to be recorded as an audio file.

...

In terms of empty space, that’s completely normal. The LTC in the truck (and a lot of other places) is ‘time of day’ time code. So in the DAW session there’s hours between the rehearsals and the performance (both of which are recorded ad edited together).

...

From https://github.com/bbc/rd-iic-audio-reaper_adm/issues/19

WernerBleisteiner commented 3 years ago

Hi! If it get's down to discuss applicability if BWF bext chunk in ADM, would you mind having a look also at my question, please? https://github.com/ebu/ear-production-suite/issues/22 Thanks