Posts Tagged ‘virtualdub’

Free way to trim a WMV File

Friday, August 12th, 2011

The other day I wanted a 5 minute segment from a WMV, Windows Media Video, file. To be more precise, the codecs used are WMA2 for audio and WMV3 for video, according to VLC.

My normal tools of choice for taking clips from video are VirtualDub, and Avidemux. Unfortunately, both of these tools failed on the WMV file. Both could preview the input file, but neither was able to create a new video file that worked. I tried both the fast “copy” method, and the full re-compress method. This didn’t surprise me too much, neither application is known to work very well with Microsoft WMV files, and I think I’ve run into this issue in the past. Both work great for AVI, MP4, and various other files that I’ve worked with over the years.

I really wanted this video clip, so I did some searching for some new tools to use.  I found AsfBin, which is free for non-commercial use. It worked like a charm.  The preview window seems a bit quirky for me, but the resulting file works fine, so I’m happy.



Recording from a Hauppauge HVR-950Q USB TV Tuner to VirtualDub

Saturday, March 6th, 2010

The 2010 Vancouver Olympics are over. IMHO, they were awesome. Unfortunately, it’s time to get back to work. Almost.

I want to record some video from Shaw On Demand of a curling event that I attended live. I have access to a Hauppauge HVR-950Q USB TV tuner – a great piece of hardware paired with terrible software.

I had multiple issues, but in the end, as I type this, I have my old laptop capturing the video from the composite (i.e. “RCA” video) input from the Shaw Digital Box.

I started this adventure on my day-to-day laptop, a 1.5 year old laptop running Vista. On this computer, the WinTV 6 software could not properly display the signal from the composite input. It would get about 1 frame per second, plus some really weird “chipmunkesque” spurts of audio. It was unusable to view the composite feed, never mind trying to record from it. I then tried the newly released WinTV 7 software from the Hauppauge website. It was worse – it is even more bloated, even slower, and still unable to view the composite input properly. Note: I have previously watched the Over-the-Air HDTV channels with this unit, so it’s specific to the composite input, and it might be specific to my laptop. There is a big difference between OTA HDTV and composite – an OTA signal is compressed MPEG2 and the unit passes it directly over the USB to the TV tuning software, whereas, the composite is fed in some sort of raw format that requires massive USB bandwidth – i.e. there is no on-device MPEG encoding.

I tried VirtualDub next, the free video capture software that I’ve used from time-to-time for years. VDub could preview the signal fine, and with much less processor overhead. Unfortunately, when I tried to start the capture, I kept getting this error: “The Capture device does not support the video format”. I eventually find a solution to this error, but only after I tried my ancient laptop.

I tried using my ancient HP Celeron 1.1Ghz laptop. It runs XP, and my theory was that the Hauppauge software just doesn’t like Vista. This might be true. I was able to use the WinTV 6 software on the old laptop fine… eventually. You have to run the install, and the setup from an administrative login. Otherwise, the software will crash hard, without giving any clues as to why. Watching the composite input in WinTV 6 used a lot of the CPU, but it is a 5 year old laptop, so it’s all relative. It was unfortunately, far too slow to do a live encoding to MPEG.

So, I knew that the composite signal worked reasonably well. I tried VirtualDub on the ancient computer. I got the same error when trying to start the capture. The fix? The trick is to look at the VirtualDub device properties to see in which format the preview was coming in. In my case, it’s 720×480 UYVY. Once I set this on my custom capture format, VirtualDub worked fine. I’m not able to encode to MPEG live, I’m using HuffYUV and 10s of GB of hard drive space to capture 2 hours of video, but it will work. I’ll have to transcode to MPEG4 later.

In the end, I could probably have used VirtualDub on the first laptop that I tried now that I knew how to get a compatible capture format. According to Google, there aren’t many people who have had these problems… I feel special. Sometimes I wish things would “just work.”