Frame Rate Changed When Save In COPY Mode

[oldtrarunner]

I’m trying to trim the start of a .wmv file created by an IBM SmartCloud Meeting. I’m using avidemux in Copy mode for both video and audio. I’m using AVI Muxer, Muxing Format: AUTO, for the output format. When I save the video, even if I do not trim, the output does not seem to preserve the input frame rate, and the file plays at 150x speed, making it unusable.

My avidemux is release 2.6.6.

MediaInfo shows the following for the input file.

General
Complete name : C:\keith\work\GWU\tagup_21jan2014.wmv
Format : Windows Media
File size : 19.8 MiB
Duration : 59mn 38s
Overall bit rate mode : Constant
Overall bit rate : 46.5 Kbps
Maximum Overall bit rate : 3 494 Kbps
Encoded date : UTC 2014-01-21 18:59:23.192

Video
ID : 2
Format : VC-1
Format profile : Advanced@L2
Codec ID : WMVA
Codec ID/Info : Windows Media Video
Codec ID/Hint : WMV
Description of the codec : Windows Media Video 9 Advanced Profile
Duration : 59mn 40s
Bit rate mode : Constant
Bit rate : 2 048 Kbps
Width : 1 280 pixels
Height : 800 pixels
Display aspect ratio : 16:10
Frame rate : 0.100 fps
Nominal frame rate : 15.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Compression mode : Lossy
Bits/(Pixel*Frame) : 20.000
Stream size : 874 MiB
Language : English (US)

Audio
ID : 1
Format : WMA
Format version : Version 2
Codec ID : 161
Codec ID/Info : Windows Media Audio
Duration : 59mn 38s
Bit rate mode : Constant
Bit rate : 1 411 Kbps
Channel(s) : 1 channel
Sampling rate : 16.0 KHz
Bit depth : 16 bits
Stream size : 602 MiB
Language : English (US)

MediaInfo shows the following for the output file.

General
Complete name : C:\keith\work\GWU\avidemux\xxx.avi
Format : AVI
Format/Info : Audio Video Interleave
File size : 11.8 MiB
Duration : 27s 200ms
Overall bit rate : 3 636 Kbps

Video
ID : 0
Format : VC-1
Codec ID : WMVA
Codec ID/Info : Windows Media Video
Codec ID/Hint : WMV
Duration : 23s 867ms
Bit rate : 4 023 Kbps
Width : 1 280 pixels
Height : 800 pixels
Display aspect ratio : 16:10
Frame rate : 15.000 fps
Bit depth : 8 bits
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.262
Stream size : 11.4 MiB (97%)

Audio
ID : 1
Format : WMA
Format version : Version 2
Codec ID : 161
Codec ID/Info : Windows Media Audio
Duration : 27s 200ms
Bit rate : 16.0 Kbps
Channel(s) : 1 channel
Sampling rate : 16.0 KHz
Bit depth : 16 bits
Stream size : 53.1 KiB (0%)
Interleave, duration : 1404 ms (21.06 video frames)

It seems obvious that the problem is the Frame Rate changing from 0.100 for the input to 15.000 for the output. Is there anything I can do to get this to work? Does avidemux simply not support this unusual 0.100 Frame Rate?

Thanks for your help.

[poisondeathray]

Use asfbin to trim wmv

[oldtrarunner]

Thanks for the reply, poisondeathray.

I used afsbin and got a usable result but the split was very ragged. On Windows Media Player it takes about 10 seconds before the video fully renders (it displays immediately as fuzzy). Using VLC media player, it takes 28 seconds before any video renders, and once it renders a bit of the audio is lost (I assume things are just syncing up again and the audio was behind?).

With afsbin, I assume again that the problem is associated with the unconventional 0.100 frame rate. In this case, afsbin says it doesn't have the wmva codec so it can't do precise cutting and will align with the first key frame before the specified time. I would have assumed this would result in a clean cut. Is there anything I can do to help afsbin achieve a better result?

Thanks again for your help.

[poisondeathray]

I suspect your SmartCloud meeting is producing a VFR (variable frame rate) WMV. This means the FPS goes up and down according to activity. When there is little to not activity it might drop down to fractional FPS rates . This is great for saving bandwith and reducing filesizes.

Unfortunately, this also means it's very difficult to edit, and keep in sync , because most editing software assumes CFR (constant frame rates) .

There are probably other issues - mediainfo suggests the filesize is 874MiB + 602MiB for the video & audio , but the actual filesize is 19.8MiB ? There are many things that are peculiar about this . If you can upload it , I can take a closer look

[oldtrarunner]

Yes, I would expect VFR to be used. The video is a recording of presentation materials being streamed on the internet, so size is important.

I've attached the file I've been working with - my first time using an attachment here, let me know if there are any problems!

Thanks.

[poisondeathray]

It is variable, but only minimally so (it doesn't make massive jumps up & down) .

Where did you want to cut in terms of timecodes ? The in/out points say according to a media player ? Cutting won't be exactly precise unless you re-encode the file , but cutting should be possible with ffmpeg which preserves timecodes

Usually, VFR is meant for final delivery . It' s not good for recording slideshows/net meetings/screencasts etc... if the intent was to edit

It's should be possible to reduce the video stream drastically from what you have now using VFR h.264 , because there are only 359 frames, but only 2 are unique . (About 14MB of the 20MB is audio, but 2 video frames would only take a few KB)

[oldtrarunner]

Unfortunately, we are just using the IBM SmartCloud tool as users, we don't have any influence on how it works. This tool provides audio, slides, and webcam video simultaneously, so I think they were using any trick they could think of to cut down on size.

The recordings we normally deal with are to support online classes and the video is started about 15 minutes ahead of the official start of class. There are occasionally technical issues we need to resolve and we need the 15 minute buffer to address them. Following class, we then want to trim off this buffer time so students don't have to deal with it if/when they view the recordings.

In the attached video I was using for testing, I arbitrarily trimmed 6 minutes. But the behavior is he same if I trim nothing and save output. It is particularly interesting that trimming 27 seconds (to see what would happen if I tried to avoid the 28 second delay I was seeing with VLC) results in a file that VLC never renders (well, at least not for several minutes) while Windows Media Player can still play with its "usual" 10 second full rendering delay.

Unfortunately, re-coding the video to a constant frame rate and then editing is not a good option for us. The time and space to use this approach are deal killers.

And some background to help understand our "expectations": The IBM SmartCloud recordings can also be done in .mov. This is our current baseline. We are able to trim these files using QuickTime Pro without getting a ragged start. But we do not like being dependent on this because most of our business is Windows based.

Thanks again for your help. Any ideas you have on how to get a clean trim would be appreciated. I will continue to experiment.

[poisondeathray]

In this case, afsbin says it doesn't have the wmva codec

I'll look into it farther, but the fourcc "WMVA" is no longer supported by microsoft - that might contributing to some of the issues

Codec ID : WMVA

http://www.fourcc.org/wmva/
http://msdn.microsoft.com/en-us/library/windows/desktop/bb970509%28v=vs.85%29.aspx

'WMVA' Content encoded with the older, obsolete version of the Windows Media Video 9 Advanced Profile codec.

Usually WMV3, or WVC1 (WMVA is actually subset of WVC1) is normally used. You might be able to "patch" the fourcc to make it "behave" like a normal video, or see if your software can record directly in WVC1 (it might be called "VC-1" there)

[poisondeathray]

What format of quicktime does it record in ? Can you post the mediainfo report for that ?

[poisondeathray]

I'm not getting any noticable startup delay during playback when cutting with asfbin ... in several media players, kmplayer, mpchc, ffplay ,wmp... EXCEPT VLC , which plays audio, but black screen

It might be VLC related issue , or the version of VLC. I tested on 2.0.5

Which is interesting, because VLC relies on ffmpeg libraries, yet ffplay is able to play the cut samples fine....

Seeking is fine/snappy in the media players on the cut sample, except WMP, which seems to incur audio issues when seeking

What version of asfbin are you using ?

[oldtrarunner]

Easiest question first. I'm using asfbin version 1.8.2.903.

While we don't own the software being used to generate the recordings, I can (and will) pass along you recomendations to IBM and maybe they will act. They do make period upgrades to the tool.

Thanks for testing a broader set of players. I picked the ones I thought the students would be most likely to use. But if VLC really is just an outlier, then maybe it is not as big of a concern. I guess I'll have to find a Mac somewhere and see how the trimmed files play there.

The .mov files generated by the IBM SmartCloud have the following MediaInfo.

General
Complete name : C:\keith\work\GWU\12573041d79505d6324a72f0a0472d1a b4e98283_1.mov
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt
File size : 34.5 MiB
Duration : 1h 3mn
Overall bit rate : 76.2 Kbps
Encoded date : UTC 2014-01-22 23:20:08
Tagged date : UTC 2014-01-22 23:20:08

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L2.2
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=10
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1h 3mn
Bit rate : 12.2 Kbps
Width : 1 280 pixels
Height : 800 pixels
Display aspect ratio : 16:10
Frame rate mode : Variable
Frame rate : 0.225 fps
Minimum frame rate : 0.002 fps
Maximum frame rate : 66.667 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.053
Stream size : 5.50 MiB (16%)
Title : Visual Stream
Language : English
Encoded date : UTC 2014-01-22 23:20:08
Tagged date : UTC 2014-01-22 23:20:08

Audio
ID : 2
Format : ADPCM
Format profile : U-Law
Codec ID : ulaw
Duration : 1h 3mn
Bit rate mode : Constant
Bit rate : 64.0 Kbps
Channel(s) : 1 channel
Sampling rate : 8 000 Hz
Bit depth : 16 bits
Stream size : 29.0 MiB (84%)
Title : Audio Stream
Language : English
Encoded date : UTC 2014-01-22 23:20:08
Tagged date : UTC 2014-01-22 23:20:08

The output from the QuickTime Pro trim has the following MediaInfo.

General
Complete name : C:\Users\keith\Downloads\EMSE6589RC2-Nguyen_04a_.mov
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt
File size : 29.0 MiB
Duration : 51mn 8s
Overall bit rate : 79.1 Kbps
Encoded date : UTC 2014-01-23 05:56:07
Tagged date : UTC 2014-01-23 05:56:15
Writing library : Apple QuickTime 7.6.6
com.apple.quicktime.player.movie.audio.m : (Binary)

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L2.2
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=10
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 51mn 8s
Source duration : 1h 3mn
Bit rate : 12.8 Kbps
Width : 1 280 pixels
Height : 800 pixels
Display aspect ratio : 16:10
Frame rate mode : Variable
Frame rate : 0.225 fps
Minimum frame rate : 0.002 fps
Maximum frame rate : 66.667 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.056
Stream size : 4.65 MiB (16%)
Source stream size : 5.50 MiB (19%)
Language : English
Encoded date : UTC 2014-01-22 23:20:08
Tagged date : UTC 2014-01-23 05:56:15

Audio
ID : 2
Format : ADPCM
Format profile : U-Law
Codec ID : ulaw
Duration : 51mn 8s
Bit rate mode : Constant
Bit rate : 64.0 Kbps
Channel(s) : 1 channel
Sampling rate : 8 000 Hz
Bit depth : 16 bits
Stream size : 23.4 MiB (81%)
Language : English
Encoded date : UTC 2014-01-22 23:20:08
Tagged date : UTC 2014-01-23 05:56:15

[poisondeathray]

I would say the majority of "non techy" people on Windows use wmp as the default player - because they don't know any better . (It's a poor player with many issues)

VLC is probably the next most popular, but the newest version still has black screen with cut files. Not sure why

It seems to me a growing proportion of students opt to get Macs / Macbooks for their own computers (maybe they are more "cool" ? ) , but most institutional and educational systems (at least in Canada) are still Windows based

[oldtrarunner]

What would you consider to be a good player for WMV-type files? We make recommendations to our students, though I don't know how much we really influence them (they are grad students and some can be a bit stubborn). We certainly can say DO NOT use VLC if that is the only problem.

I was pro-Windows until I got my last laptop a few month ago (my 2004 Inspiron finally blew a gasket). It came with Windows 8. It took me three days to make it look like a PC. Convinced me to consider a Mac for next time.

I've passed the asfbin trimmed file along to someone who will try it on a Mac. I'll let you know what they find.

Thanks.

[oldtrarunner]

The file trimmed using asfbin plays fine on Mac using QuickTime!

I'm still interested in your recommendation of a good WMV player.

Thanks.

[poisondeathray]

MPCHC would probably be a good choice for WMV / ASF . There is a portable version (doesn't need installation or messing with system registry)

[oldtrarunner]

Thanks. I went ahead and downloaded the portable MPCHC as you suggested. It looks like a nice project that worked well with my trimmed WMV file. But I got the impression from reading some of the comments that it might also play MOV, however it did not. Is there some additional action I can take for it to play MOV?

[poisondeathray]

Yes you can configure the internal or external filters . "Internal" means not system installed in this case, and internal to MPCHC

Right click , Options => Internal Filters => Under Source Filters, make sure MOV is checkmarked . Under transform filters, h.264 should already be enabled (h.264 because mediainfo says your MOV uses h.264)

[oldtrarunner]

I have an MP4/MOV Source Filters entry that is checked and an H264/AVC Transform Filters entry that is checked. I assume these are the correct entries. I'll attach a snapshot.

My previous post may not have been precise enough. The player opens and says it is playing but nothing ever renders and the progress bar never moves. I played with the buttons a bit (guerrilla style) with no change. So perhaps the problem is related to these MOVs not being quite customary.

On a positive note, the next generation of the IBM SmartCloud tool has a new Meetings option and this version records WMV using a different codec. The following is from MediaInfo.

Video
ID : 2
Format : VC-1
Format profile : MP@HL
Codec ID : WMV3
Codec ID/Info : Windows Media Video 9
Codec ID/Hint : WMV3
Description of the codec : Windows Media Video 9 - Professional

When I trim these new recording with asfbin, the start is not ragged when viewed with WMP. Other issues with the next generation tool prevent us from using it now. But at least it is clear that IBM has the technology to improve the current tool, so we will request that.

[poisondeathray]

Codec ID : WMV3

That's the more common fourcc I mentioned earlier, which MS has wide support for


Not sure about your specific MOV's . Quicktime/MOV's are a PITA on Windows, source of many problems, gamma shifts. If you can update the IBM software and it works with splitting ok that would be the way to go

[oldtrarunner]

That's the plan!

Thanks again for all your help. I hope I won't be torturing you again soon.

[poisondeathray]

It's no problem at all . I was only asking about the mov as a "plan b" , but unlike the report for the wmv, nothing in the mediainfo for the mov suggests anything abnormal