Starting January 10th, WhippleHill moved the multimedia back-end of their Podium platform to Brightcove for a number of reasons I won’t cover here but all positive in the grand scheme of things. But, this did leave me with the opportunity to look at and change from what I was doing with our video pre-processing in their old flash-based system since the Brightcove back-end provides much more flexibility on device support with HTML5 MP4 players in addition to flash capability.
So, starting early January 10th, I began testing. The main process I have been performing around video relate to our Community Meetings, Assemblies and Performances we have and want to make available for the larger community. The Brightcove Recommendations and Specifications page was helpful, but not all that specific. This became more of a trial and error to see what would be acceptable for us and the type of video we were going to be posting now in the new and improved environment.
If you are unsure what sizing and settings will work for you, I suggest you do what I did. Take a 1 min clip of video that is representative of the type of video you will be posting and export that to H.264 MP4 format a few different ways and upload them into your Whipple Hill Media Gallery to see how they show on your Desktop computers and mobile devices. Encoding/exporting 1 minute of video into the different formats will give you a better sense of exactly what happens when you change a setting here or there. It will also provide clarity on file size. Based on how you export your MP4 file, that 1 minute video filesize can range from under 20 megs into 30megs and up. This is extremely useful to understand and be aware of when you process your video. It also allows you to be able to know a 30 minute video with your preferred settings will be x megs when you go to upload it. Brightcove typically has a 2 GB file upload limit and currently WhippleHill has a 1 GB upload limit. So, knowing that and the roughly the size of video encoded with your settings will give you a guideline early in the process on how you should proceed.
Another aspect to consider is what devices people will be accessing the video from. There will be more and more people viewing our video from iOS-based and Android-based devices in the coming months and years, but today most people are still going to want to view it via laptop or desktop. This is important because it helps guide you on your priorities on sizing of the video. If you go lower in resolution, Brightcove does size it up or down very nicely for devices that want to natively go larger, but in my opinion it is probably better to get the video into Brightcove at a reasonable high resolution so even the full-screen player on a widescreen laptop or desktop monitor will look good.
One item to note: Apple does have an .m4v file format they use as a container for video files, but this is NOT the same as MP4. More information on this format can be found here. Just saving a movie out of Apple media applications to the .m4v format will not get you there.
I do most of the initial processing and editing in iMovie then export using QuickTime. You can export from iMovie under the ‘Share’ menu
Change the Export Pop-up to Movie To MPEG-4
Then into the ‘Options’ button.
After a lot of testing my MP4 settings for file uploads are ideally this –
Video Format: You want to keep the format H.264.
Data Rate: The most important variable that dictates the size and quality of the resulting file. 3500kbs might be a little overkill, but in testing north and south of that, it seemed that was the cutoff of quality that I was happy with.This setting and the Image Size really are the reasons for quality and file size to fluctuate.
Image Size: Using 1280×720 because the video I have from the HD camera is going to be 16:9 and I wanted larger resolution for the desktop full-screen player. This is way overkill for iPhones and iPads, but still looks nice for desktop full-screen viewing. Brightcove gears down for devices that cannot handle large resolutions really nicely.This is something along with Data Rate you can use to decrease the size (and probably the quality of the resulting MP4)
Frame Rate: Typically from most cameras, your video will be recorded at 30FPS (frames per second) but this is often many more frames and data than needed. I geared down on the frames per second because it does save some file space and it is really not noticeable for viewers to have be at 30 fps. Also, in my testing, I found going to 15fps really increased the turnaround on encoding at the Brightcove end for some reason. Video pre-processed at 15FPs came back live into the Whipple Hill Media Gallery from Brightcove faster perhaps because there was half the number of frames to mess with on their end.
With these settings exporting out of something like iMovie, Final Cut Pro or QuickTime 7 Pro, you get about a 27.6 meg MP4 file for a minute of video. This means in my screenshot example of around 30 minutes of video I get an exported file of around an 800 meg file to upload which keeps me under the WhippleHill limit of 1GB. Most of our videos are going to be around 30 minutes or so long or we can break them up into parts that are 30 minutes or less, so this works for us.
If your video durations differ – perhaps you routinely want to post an hour of video. You might want to gear that resolution down to 640×360 and lower the Data Rate to to 2500 or so. In my testing with Podium and Brightcove, I was not happy with anything less than 2500kbs no matter want the resolution was. 640×360 is a nice step down in sizing, but the Data Rate is the biggest driver of that MP4 file size. If you are processing a really long video like an hour or more, you might be better served going with a higher data rate like 3500kbs and just breaking up the video into parts that make sense for the viewer.
Just as I didn’t like anything less than the 2500 on the Data Rate side of things even in 640×360, I didn’t seem to see any real difference going higher than 3500kbs no matter what the resolution was. I tested 4000kbs and higher, but the huge increases in file size did not provide any better quality in my opinion and after looking and many, many, many 1 minute videos.
Hope this helps and your mileage may vary but this testing process can be very helpful in understanding the dark art of video processing and getting a handle on the positives and negatives of the switches and settings you can tweak to get the results you want.