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Paul Rogati
weird playback speed
on Aug 31, 2009 at 3:16:45 pm

I have a new configuration - using a G5 Power Mac (2x2GHz, 4GB RAM, running OS 10.5.8), a AJA Kona LH input card ingesting component video and analog audio.

While recording, everything seems fine - video and audio are monitoring normally. But when I play back the recorded file (H.264) the audio is a chipmunk with the video playing normal speed.

I downgraded the Kona drivers from 6.0.3 to 5.1. Now the playback (in QT Player) seems to be the reverse, with fast video playback and normal audio, but playback is inconsistent with replays.

Anyone know what might be going on? - Paul


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Paul Rogati
Re: weird playback speed
on Aug 31, 2009 at 3:49:36 pm

I'm thinking it might be a Kona issue rather than a Wirecast issue: I installed QuickTime Broadcaster to see if the behavior was any different. It isn't. Thanks. - Paul


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Craig Seeman
Re: weird playback speed
on Aug 31, 2009 at 4:08:06 pm

It may well be the Kona card. Can you try a camera with firewire input?
Please post complete setup specs including all versions of software and hardware. Make sure you're using Wirecast 3.5.4.



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Paul Collins
Re: weird playback speed
on Sep 10, 2009 at 5:06:41 pm

With H.264 streams and recordings, whether Wirecast or QT Broadcaster, there seem to be audio settings that cause problems like this. Try different sample and bit rates! I'm still trying to find the rhyme or reason for this, but certain rates have caused severe audio sync and speed problems (and loss of audio for some but not all streaming viewers).

Web/cablecasting: http://ashlandtv20.com
Software Development: http://www.gracion.com


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Paul Rogati
Re: weird playback speed
on Sep 10, 2009 at 6:27:16 pm

Thanks for the post Paul. I was beginning to think I was creating unique problems. One thing I discovered is that the weird audio speed shows up on the record Mac (in this case with the AJA card), but will play fine on another Mac. I'm thinking that implicates the Kona, but I have issues like you mention with other configurations. I have a handful of Wirecast system setups - some straight Firewire in, one using a Blackmagic card, and one with an AJA Kona LH. I am about to embark on adding HDV to two new setups (oh joy!). - Paul


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Craig Seeman
Re: weird playback speed
on Sep 10, 2009 at 6:52:02 pm

Paul,
Let me know ASAP when you find which settings cause this in Wirecast and test in QTB with the same settings. They're both using Apple's codecs so it may be reproducible in both.



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Paul Rogati
Re: weird playback speed
on Sep 29, 2009 at 4:22:30 pm

I apologize for my slow responses. Once the school year started I have little time to test. Here is an interesting round of data. Yesterday I made a recording with the same settings I had used a week ago with no problems, but this time the audio was slooow. My starting settings were H.264, 15fps, AAC audio at 128kbps, 44.1kHz with Better compression.

Excuse the jump because I discovered something today. I was able to correct the audio with Amadeus Pro and when I went to recombine the fixed audio track with the normal speed video track in QTPro I discovered the following Durations in the file properties:
File - 1:36:48.51
Video Track - 0:48:24.30
Sound Track - 0:48:24.30
Hinted Video - 0:48:24.30
Hinted Sound - 1:36:48.51

I have another post in this forum about Hint tracks getting messed up, usually the audio hint track is missing, so I'm suspecting there might be a correlation.

Back to compression settings. Once I noticed the aberrant audio, I made a series of test recordings, and the setting that made a difference was stereo/mono: mono recorded normally, stereo recorded slow. But what I didn't test (based on today's discovery) was recording and NOT having Wirecast hint the file in real time.


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Paul Rogati
Re: weird playback speed
on Sep 29, 2009 at 6:57:46 pm

Addendum: system details

Mac mini 2.26 GHz, 4GB RAM, OS 10.5.8
Wirescast 3.5.4 with HDV option
Canon VIXIA HV40


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Paul Collins
Re: weird playback speed
on Oct 2, 2009 at 4:37:06 am

I try to keep hinting off, as my recordings are not directly published without some sort of conversion. The problem recordings I got with "chipmonk" fast sound speed were probably not hinted, and certainly the good recordings I've gotten lately with stereo AAC recording are not hinted.

Web/cablecasting: http://ashlandtv20.com
Software Development: http://www.gracion.com


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Paul Collins
Re: weird playback speed
on Sep 10, 2009 at 9:35:54 pm

I'll check later when I have time. You'd think if simply using certain encoding settings caused these problems, we already have heard about it. Maybe it only happens with slower frame rates (such as 10 and 15 FPS, which I use)--I think someone else mentioned this in connection with a slow rate.

Web/cablecasting: http://ashlandtv20.com
Software Development: http://www.gracion.com


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Craig Seeman
Re: weird playback speed
on Sep 16, 2009 at 6:08:01 pm

Maybe this is a sample rate issue.

Check to see what sample rate you're recording with Wirecast.
Test with 32kHz, 44.1kHz, 48kHz and see if the results differ.

If Quicktime Broadcaster shows the issue and the file playback changes from system to system and the Kona is impacting it, I'm thinking it might be system vs file sample rate.



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Paul Collins
Re: weird playback speed
on Sep 21, 2009 at 5:16:19 pm

I did a brief test streaming 15 FPS video with MPEG-4 audio 48kbps/24kHz sampling, mono. Opened the stream in QuickTime Player 7.6.4 and the audio was chipmunked (sounded like 2x speed). On a hunch, I changed to stereo audio and then the audio was correct. Could be a coincidence, but interesting.

Web/cablecasting: http://ashlandtv20.com
Software Development: http://www.gracion.com


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Craig Seeman
Re: weird playback speed
on Sep 21, 2009 at 5:31:49 pm

I think someone also mentioned that mono results in chipmunk but stereo is OK.
I'm wondering if there's another correlate.
Can you try doing the same thing at 30fps using the same sample and bit rate and tell me what happens?



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Paul Collins
Re: weird playback speed
on Sep 22, 2009 at 3:59:03 pm

Craig, 30 FPS didn't make any difference. I could make chipmunk sound mode (approx. 2x audio playback speed) come and go by switching between mono and stereo with other settings the same. So I guess there's a bug with mono mode in either the AAC encoder (MPEG-4 audio setting) or decoder in QuickTime.

Web/cablecasting: http://ashlandtv20.com
Software Development: http://www.gracion.com


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Craig Seeman
Re: weird playback speed
on Sep 22, 2009 at 4:42:17 pm

Thanks for that. I sent this info to Telestream so I'd suspect they'll have a fix in the not too distant future.

BTW what version of Quicktime are you using?



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Paul Collins
Re: weird playback speed
on Sep 22, 2009 at 5:36:00 pm

This is with QuickTime 7.6.4 both on broadcasting Mac and receiving Mac. Seems like this might be a QuickTime rather than a WireStream issue - I've been seeing audio problems using QuickTime Broadcaster as well. I I'll try to post a bug report when I can.

Web/cablecasting: http://ashlandtv20.com
Software Development: http://www.gracion.com


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Robert Broad
Re: weird playback speed
on Jan 12, 2010 at 11:30:42 pm

Hi there, we just ran into this bug and after a few hours of troubleshooting SDP files etc, and only THEN finding this thread, we can confirm that the stereo/mono thing is the culprit.

One thing we did notice along the way, however, is that Wirecast does not seem to write as much information to it's SDP files as Quicktime Broadcaster, in particular the lines that specify the audio bit rate etc. Not sure if this has anything to do with it...

Anyways, thanks for the thread!

Robert.

Intel 2.4 GHz MBP
Mac OS 10.5.7
Wirecast 3.5.2
AV in: Built-in Firewire


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Craig Seeman
Re: weird playback speed
on Jan 13, 2010 at 12:27:46 am

Always stay current with updates. They are bug fixes. Wirecast should be on 3.5.6 and you should update your OS to 10.5.8.



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Robert Broad
Re: weird playback speed
on Jan 13, 2010 at 10:16:56 am

True enough. Just updated everything and now there are a bunch of new issues. sigh... ;-)

Intel 2.4 GHz MBP
Mac OS 10.5.8
Wirecast 3.5.6
AV in: Built-in Firewire & Epiphan VGA2USB LR


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Paul Rogati
Re: weird playback speed
on Jan 13, 2010 at 6:50:40 pm

An update, focused on the one system I have that uses the Kona LH card (Mac Pro G5, 2 GHz DP, 4 GB RAM, OS 10.5.8). Over semester break I did what updates I could - Wirecast to 3.5.6, Kona drivers to 7.1, Mac OS updates. As I geared up for the new semester, I did a recording and playback behavior was wacky (it played faster than real time and sometimes there was audio but sometimes not), and I could hear the audio cut in and out while monitoring. After several tests Wirecast crashed and I could not get it to launch without crashing (I tried deleting prefs, re-installing, downgrading to 3.5.4 and even Kona 6.0.3). Getting desperate I emailed Telestream support and they said "Wirecast does not support video capture cards". This got me to thinking (plus I was anxious to get things working for classes today). So I just uninstalled the Kona drivers - which meant I had to use a different camera that gave me Firewire, but I had one - and Wirecast came back to life and appears to be working well again. I will update with observations, but I now feel I was recording all Fall on the edge of incompatibility between Kona and Wirecast. I think I will abandon the LH card. - Paul



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Paul Rogati
more data
on Jan 27, 2010 at 4:11:33 pm

Another system: Mac mini 2.26 GHz Core 2 Duo, 4 GB RAM, OS 10.5.8, Wirecast 3.5.6.

Record settings: H.264 (Main), 512x288 pixels, best quality (no bit rate constraint), 30 fps, key frame every 90, audio 64 kbps 44.1 kHz "best" 16 bit mono
Stream setting: LAN - H.264 default

Last week I started both the record and stream and tried to watch the stream remotely. The stream started with chipmunk audio and then the audio ceased, so I gave up watching. The lecture recorded fine.

This week I decided to leave things as is and just record. The audio in the recording was exactly double speed - I was able to change the timing to 50% in Amadeus Pro and now have a good file. So with no change in setting, one week recorded fine and the next didn't.

I noticed the RTP Payload in the Packetizer settings was H.264 Video (which seems to be the default). I have had success in the past changing that to QuickTime, so I have changed that and nothing else. I will keep you posted. - Paul


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