VMX Audio Problems
Nair wrote:
Matt, I don't think this is a viable solution for us. Can you boost the
audio level prior to upload? We are aware of the process. The lack of
manpower and time being the reason. Thanks,
Náir
M. S. Náir
Technical Director,
(Technology & IT Solutions)
ORCA Media Inc.
89 Main St, City Center
Montpelier, VT 05602
Phone: (802) 224 9901
Fax : (802) 223 0432Kenric Wrote:
Kenric wrote:
Not sure, I'm asking Nair this question. I don't think we have time to check every program that comes down on VMX; we assume that the the person doing the uploading has checked that the program is ready for air.
Oh, I just got this week's mass DVD in the mail.
Kenric Kite
ORCA Media
89 Main Street, City Center
Montpelier, VT 05602
www.orcamedia.net
(802) 224-9901
kkite@orcamedia.net
On Jul 1, 2008, at 11:39 AM, Matthew Goudey wrote:
Just checked the file. It is really low on the original. So, if you want, once you get the MPEG2 from the VMX you could run it through Compressor with an audio gain and boost the level. If you decide to do this let me know and I will make a quick video tutorial on how to if you don't already know.
Matt
On Jul 1, 2008, at 11:22 AM, Kenric Kite wrote:
Thursday would be much better, especially this week. Thank you!
On another matter, we are running "The Cost of the War" series yesterday and today (it's on right now) and there is very low audio. Not really audible, even when the TV is turned up all the way.
Kenric Kite
ORCA Media
89 Main Street, City Center
Montpelier, VT 05602
www.orcamedia.net
(802) 224-9901
kkite@orcamedia.net
On Jul 1, 2008, at 10:54 AM, Matthew Goudey wrote:
Tell me when you need it by and I will get it on the VMX by that day.
On Jul 1, 2008, at 9:44 AM, Kenric Kite wrote:
Matt,
no apologies, pleeeeeze! I just want to know if the diocese is now using VMX or still sending out. The problem for us is that Friday is a bit late for getting it.
Kenric Kite
ORCA Media
89 Main Street, City Center
Montpelier, VT 05602
www.orcamedia.net
(802) 224-9901
kkite@orcamedia.net
On Jul 1, 2008, at 9:39 AM, Matthew Goudey wrote:
My mistake Kenric, sorry.
I uploaded the video on Friday, but did not get to publish the page until yesterday. So, it was there, on the VMX server, but not able to be downloaded because I was a slacker... I will make sure that does not happen again. I will make sure they are available by Friday for download.
Again, I am very sorry about this. I am still trying to figure out an efficient way of uploading all our content and having it available immediately.
Won't happen again.
Matt
On Jul 1, 2008, at 9:33 AM, Kenric Kite wrote:
Matt,
Just got my VMX daily digest. The Catholic Mass there is listed as 6/29/08, which has passed. The Masses we receive through the mail are for the Sunday upcoming. Does this mea we are now to download the most recent VMX file, or is the diocese still sending out videos? They have not contacted me about it.
Thanks,
Kenric Kite
ORCA Media
89 Main Street, City Center
Montpelier, VT 05602
www.orcamedia.net
(802) 224-9901
kkite@orcamedia.net
Our audio is normalized at
Our audio is normailzed at VCAM but some of our content can lean toward
the low side. Seeing as VCAM and ORCA might represent opposite ends of
the db range perhaps it would be beneficial for all VMX users if we
continue this conversation and run some tests. One that comes to mind
is; if we each were to upload a test clip of bars and tone at -12db,
then download and transcode each others test clip and see if -12db is
maintained. If not we obviously have a larger issue. But if there's no
problem, and if we felt up to it, we could even go as far as testing
the db level of the clip once cablecast. This could possibly shed some
light on any serious inconsistencies in our server settings if there
are any.
Check your server settings
Check your server settings at ORCA. I was
told that the VMX shows from ORCA are a little HOT on the audio side.
So if they play fine for you, you may be playing back at a low audio
setting. Then if you bring in a show that is normalized at -12 db
(digital equivalent to 0db analog) it will sound low for you.
Our audio is normalized here, after much experimentation and adjustment to our server settings.
I will make a video tutorial for those interested in using
Compressor for adjusting any overdriven or underdriven audio.
Compressor comes with the Final Cut Studio suite of applications, and
only Compressor 3 (FCPStudio 2) can do what I am talking about.
But as a note, it is the responsibility of all access centers to
normalize their audio BEFORE posting to the VMX site. If anyone needs
help figuring out how to normalize, post it here. Individual emails are
way less effective, as here, any and all members can respond with
solutions.
Thanks for any contributions to this thread.
Matt Goudey
Video Technology Coordinator
Vermont Community Access Media
208 Flynn Ave Suite 2G
Burlington, VT 05401
802.651.9692
Hey I like this test idea.
Hey I like this test idea. I'll post a test clip of bars and tone at -12db from here later today. Rebecca Padula, Channel Coordinator Lake Champlain Access Television rebecca@lcatv.org www.lcatv.org 802-862-5724
Great job being on the
Great job being on the ball, Rebecca. I just downloaded your tone and ran it through the gamut. Here are my preliminary findings.
-12dbTone uploaded from LCATV. Downloaded by VCAM. Original MP4 file maintained -12db level on download. Audio extraction elevated the level to -9db and VMX transcode with audio normalization lowered levels to a final -24db. This is a problem.
Another interesting fact of this process is that the tone is not constant after the "normalization" process. The exrtraction wavers from -9 to -8, and the final wavers from -22 to -23. The original stays constant at -12.
I will be running some more tests on some actual file, comparing the mp4 with the mpeg2 files.
I will also be posting a bit in the general discussion forum about what steps need to be taken to help fix this. We are, all of us, going to have to work together on this. Keep our eyes and ears out in the other forum.
Thanks.
Matt
Matt Goudey
Video Technology Coordinator
Vermont Community Access Media
208 Flynn Ave Suite 2G
Burlington, VT 05401
802.651.9692
Thanks for working on this.
Thanks for working on this. I've been doing some testing and have changed a few things today, but I don't know that it is completely solved yet. But here's the update:
1. The normalization application, though the documentation strictly states that the default is -12dbfs, when running the bars and tone through it (which start at -12), they come out at -9. So it was applying a +2.76db gain. I added a flag in to normalize to -14.76, tested it out, and the bars and tone remain at -12db. I then integrated this change into the VMX application.
2. The MPEG-2 application was buggy and had not taken the most recent change I applied, and was thus still applying a volume adjustment in the transcode. I removed this and rebuilt the application.
3. For better logging, I changed some of the log file names. I have documented this in it's own post that is a sticky at the top of the technical support forum. Definitely check this out.
Can you please run a VMX update (the version should say 1.5.1 after you update) and test this again? The issue is that the MPEG-2 transcode is still somehow adjusting the audio. I tested going back to MPEG-4 instead of MPEG-2 and the file stays at -12. But something in the MPEG-2 conversion is screwing it up. I have been working on this all morning and haven't been able to resolve it. If you want to try to help me out, here's the basic process:
- run the VMX update
- delete the log files associated with the LCATV bars and tone file
- run the MPEG2 button on the VMX app. This will leave you with a 'Audio.wav' file and the final LCATVtonetest.mpg file in VMX/MPEG2/ folder. At this point, I am running terminal ffmpeg commands and trying to play with them to see where I can get. This command will put a new MPEG-2 file in the same folder called 'commandtest.mpg'.
From here, you can open the terminal application and run this command:
/Applications/ffmpegx.app/Contents/Resources/ffmpeg -i ~/Pando\ Packages/Singles/ToneTestLCATV.mp4 -i ~/VMX/MPEG2/Audio.wav -map 0:0 -map 1:0 -f vob -deinterlace -vcodec mpeg2video -muxrate 10080000 -b -maxrate -acodec mp2 -ar 48000 -ab 224 -ac 2 -r ntsc -ildct -ilme -bf 2 -g 15 -s 640x480 -aspect 4:3 -bufsize 224 -y ~/VMX/MPEG2/commandtest.mpg
That is running the same command the VMX application uses to create an MPEG-2 file. There are a bunch of audio options in there, but the only thing that is supposed to mess with gain/levels is the -volume flag, which we are not using.
In the above command, everything after the -f flag is related to the MPEG2 file.
If you want to see a list of all possible ffmpeg options and what the flags mean, you can type this into the terminal (it will spit out a huge options list):
/Applications/ffmpegx.app/Contents/Resources/ffmpeg
OK, I've uploaded the VMX
OK, I've uploaded the VMX update. Upload some test tones and I'll let you know what I get.
P.S. what are you using to playback and test these files, final cut?? or is there a meter in quick time somewhere that I'm missing.
Rebecca Padula, Channel Coordinator Lake Champlain Access Television rebecca@lcatv.org www.lcatv.org 802-862-5724
I use Quicktime or MPEG
I use Quicktime or MPEG Streamclip to convert the audio to AIFF (PCM) and then drop that into FCP to use the meters.
Matt Goudey
Video Technology Coordinator
Vermont Community Access Media
208 Flynn Ave Suite 2G
Burlington, VT 05401
802.651.9692
Cool, I've got MPEG
Cool, I've got MPEG Streamclip working and can check AIFF files with my meters in Premiere. As a test I extracted audio from the recently posted "Button Up Vermont Panel" and it's on the hot side, running between -12db and 0. I think this was an ORCA production.
If you want to continue with some tone testing, I can now also contribute findings.
Rebecca Padula, Channel Coordinator Lake Champlain Access Television rebecca@lcatv.org www.lcatv.org 802-862-5724
If it's going between -12
If it's going between -12 and 0, that is a huge variation. it should vary between about -20 for room tone and max out at about -6 for peaks, maybe -4 at best. The average audio should be wavering between -14 and -10. That is normalized at -12. Where are the bulk of the sounds leveling at? Keep in mind, you can upload tone, and then download your own tone to do testing with Premier. If you create -12 tone, comress it, then upload it. Download it from Pando, convertit with Streamclip, then load it back into Premier and see if it is still -12. If so, you're all set. If not, post your results here.
But keep in mind this has nothing to do with your server settings for your playback. The real test is to compress a -12 tone to whatever codec your server uses (most likely mpeg2), then convert the audio to AIFF and check it, just to make sure the compression didn't change the levels (Apple's Compressor adds a +6db adjustment to MPEG2 program streams, so you have to add a -6db filter on compression) then, if all checks out, load that -12 tone into your server, use a calibrated audio meter to check your direct output from your server and make sure the meter still reads -12.(You can calibrate your meter by hooking it up to a playout deck, sending -12 tone from Premier, make sure the deck reads -12, and then adjust the meter to read -12. Then you know you have the proper settings all the way around.)
If all this is done and you still hear loud or soft audio when you monitor your channel on a television using the cable comeback, then you have to deal with how your output is being modulated by your cable provider. You can call them, broadcast -12 tone on your machine, make sure your output from the server is -12 with the meter, tell them you are sending -12 and to set your modualation accordingly. They should be able to do this fairly quickly if you've done your homework.
All in all, the process of testing took a while, but once we got to the normalization process it only took an hour or so.
Matt Goudey
Video Technology Coordinator
Vermont Community Access Media
208 Flynn Ave Suite 2G
Burlington, VT 05401
802.651.9692
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