I came in this morning and spoke with Linas about the ABA Practicum. We found that one student uploaded a 220+ MB file, only a few MB’s lower than the 250 MB limit. We were a little surprised to find out that the video was only 0:01:20 long because it was encoded at over 23 Mbps! Commercial DVD’s are encoded at around 9 Mbps and Bluray comes in at around 40 Mbps. This student was definitely going to have to re-encode their videos.
I ran a Handbrake test and found that encoding the video at 900 kbps yielded a video file that was just over 10 MB and played back at a little over 1 Mbps.
- Regular Profile
- MP4 file, H.264 codec (x264)
- Average bitrate (kbps) 900
- no other changes
Whew. Handbrake is an easy-to-use, cross-platform solution that is looking like our first choice to get these file sizes down.
Linas is going to do a survey to find out what the students are using and from there we can assist them on the phone and with screencasts.
Using Handbrake to re-encode large videos
As a sidenote, I had some difficulty with ScreenFlow capturing the Handbrake process. ScreenFlow was stopping the recording process on its own. Once I was able to capture the sequence I needed, the file was definitely corrupted during one section and that is definitely a problem. I think it has a hard time when the processors are cranking away on encoding video. I’ll still have to do some testing. ScreenFlow is new to me and I could have been doing something to mess it up.
Linas just asked how the videos from a Flip UltraHD compares in size to a Flip Ultra. From our previous testing, we recorded a Flip Ultra 15 min video that weighed in at 207.55 MB for a 0:17:58.89 (30 FPS, 64×480) 1620.58 kbits/s MPEG-4 video. We know for a fact that a 0:15:03.6 Flip UltraHD video was recorded at 9.14 mbit/s (30 FPS, 1280×720) for a final size of 978.48 MB. So the Flip Ultra, then SD videos weigh in around 18% or five-times smaller than the size of HD videos from the Flip UltraHD.