Calling all audio-saavy folks out there, I want to learn how to use Sony Vegas to create an LFE channel for the DTS audio I have.
The decoding I did got me 5 channel PCM files. The SE audio should be DTS 5.1, the PT audio should be DTS-ES.
The other question I have is this....is Vegas good for this or should I be working with something else to get all the channels set properly for use with other video projects?
Thanks in advance....I hope this wasn't too confusing.
:)
Vegas is great for creating a 5.1 track if you want to sync the track to video. Although you can't export it as a DTS 5.1 file, you can export each track separately as mono uncompressed wav's and import into a DTS encoder. But if it is a 5.1 track then shouldn't you have 6 PCM files and not 5? Or is this what you are asking, that you need to create a LFE channel from scratch?
adywan said:
Vegas is great for creating a 5.1 track if you want to sync the track to video. Although you can't export it as a DTS 5.1 file, you can export each track separately as mono uncompressed wav's and import into a DTS encoder. But if it is a 5.1 track then shouldn't you have 6 PCM files and not 5? Or is this what you are asking, that you need to create a LFE channel from scratch?
Yes....I believe the LFE for DTS audio is supposed to be extracted from the rears.
well if the LFE is contained in the rears then you could filter out any frequency above the LFE range in these channels (sorry i can't remember off hand what this frequency is). Once filtered save it as a wav and import it into vegas as the LFE channel. There use to be a filter in cooleditpro that would do this but i can't remember if audigy or other audio programs have anything similar
Jetrell Fo said:
Yes....I believe the LFE for DTS audio is supposed to be extracted from the rears.
Why do you believe this? Are there specs somewhere you've read (and remember that, AFAIK, theater DTS has totally different specs to home DTS).
While a low-pass filter would give you a LFE track, I have a feeling that there's more to it than that.
If the LFE track is matrix-encoded into the rears, similar to how a Dolby Surround track contains a surround channel matrix-encoded into the front channels, then you would need to run the audio through a theater DTS decoder to extract the intended LFE.
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Moth3r said:
Jetrell Fo said:
Yes....I believe the LFE for DTS audio is supposed to be extracted from the rears.
Why do you believe this? Are there specs somewhere you've read (and remember that, AFAIK, theater DTS has totally different specs to home DTS).
While a low-pass filter would give you a LFE track, I have a feeling that there's more to it than that.
If the LFE track is matrix-encoded into the rears, similar to how a Dolby Surround track contains a surround channel matrix-encoded into the front channels, then you would need to run the audio through a theater DTS decoder to extract the intended LFE.
Its all in the theatrical DTS white paper, I think, although I don't have the link to it. The DTS 6D decoder does a low-pass filter at 80Hz on the surround channels and that is what produces the LFE. The way I extracted it was to put the two surround channels into a stereo file, low pass filter then do a channel conversion to mono with each at 50% vol. so its not too loud. It produces a decent LFE channel that way, although I tend to roll the frequencies above 60Hz off to 80Hz and shelf it there, it gives a 'cleaner' LFE channel.
EDIT: Audacity should be able to do this.
Moth3r said:
Jetrell Fo said:
Yes....I believe the LFE for DTS audio is supposed to be extracted from the rears.
Why do you believe this? Are there specs somewhere you've read (and remember that, AFAIK, theater DTS has totally different specs to home DTS).
While a low-pass filter would give you a LFE track, I have a feeling that there's more to it than that.
If the LFE track is matrix-encoded into the rears, similar to how a Dolby Surround track contains a surround channel matrix-encoded into the front channels, then you would need to run the audio through a theater DTS decoder to extract the intended LFE.
http://www.film-tech.com/warehouse/manuals/DTSPOSTPROD.pdf
http://www.film-tech.com/warehouse/manuals/DTSSTUDIOMIX.pdf
If I've read or interpreted them wrong Moth3r, please let me know, otherwise I based my answer on these manuals.
CapableMetal said:
Moth3r said:
Jetrell Fo said:
Yes....I believe the LFE for DTS audio is supposed to be extracted from the rears.
Why do you believe this? Are there specs somewhere you've read (and remember that, AFAIK, theater DTS has totally different specs to home DTS).
While a low-pass filter would give you a LFE track, I have a feeling that there's more to it than that.
If the LFE track is matrix-encoded into the rears, similar to how a Dolby Surround track contains a surround channel matrix-encoded into the front channels, then you would need to run the audio through a theater DTS decoder to extract the intended LFE.
Its all in the theatrical DTS white paper, I think, although I don't have the link to it. The DTS 6D decoder does a low-pass filter at 80Hz on the surround channels and that is what produces the LFE. The way I extracted it was to put the two surround channels into a stereo file, low pass filter then do a channel conversion to mono with each at 50% vol. so its not too loud. It produces a decent LFE channel that way, although I tend to roll the frequencies above 60Hz off to 80Hz and shelf it there, it gives a 'cleaner' LFE channel.
EDIT: Audacity should be able to do this.
http://forum.videohelp.com/threads/201408-DTS-Theater-Disc-Dynamic-Range-questions
Don't know if any of this is relevant ..... I had tried reaching this BJ_M but I had no luck getting a response.
Very interesting documents. It sounds like, in theatres, the surround channels are played back through a crossover, the bottom end is sent to the subwoofer, with the low-pass filter set at 80Hz.
If you apply a similar filter in software, you should get the LFE channel (DTS call it the subwoofer channel). Technically, you'd also get any surround channel information under 80Hz included in this audio. I don't think this is too much of a concern, but you could improve the separation if you treated the surround channels as a stereo track and applied a non-centered audio removal filter (basically the opposite to a karaoke voice removal filter) before running it though the low-pass filter.
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Well, I just stumbled on this and did some additional research. So, basically, except for the mono releases, they are all surround sound. I always thought Dolby Stereo was just a noise reduced stereo, but it is a 4 channel matrixed surround sound system. That should be interesting to convert into DTS for my GOUT project. There seems to be some question as to whether the LFE should cut off at 80 Hz or 120 Hz, but other than that it is pretty straight forward.