I’ve already covered how to convert CamTasia 6 mp4 screencasts to flv, what concerns me is the availability of mp4-enabled players.  Do enough users have an mp4-compatible player?  If not, how many see nothing when presented with an mp4 screencast?  I’ve raised this question in the TechSmith forums.

Troy Stein, CamTasia’s Product Manager, provided some explanation but didn’t offer solutions.

“When we saw the results of MPEG4 output in our early CS 6 development work, we knew that FLV had a short shelf life. The MPEG4 files have better quality, often smaller file sizes, better playback on portable devices and produce faster than FLVs”

Currently over 98% of installed Flash players support Flash 7 and the FLV format (source: Adobe Flash Player Version Penetration, updated September 2008).  The same statistics show support for MP4 (via Flash Player v9.0.115 or better) is  limited to 89% of installed players.

This means that 11% of visitors cannot view MP4 content vs 2% of visitors who cannot view FLV content, as counted by Adobe.  The MP4-compatible version of Flash was released in 2007 (zdnet) and had over 80% penetration by July 2008.

Since Adobe’s statistics were recorded in September 2008 I wanted to see whether the results still held true now in January 2009.

I verified these statistics against real-world sites using December’s visitor count – I checked ShowMeDo.com (large screencast-based video education site, I’m a co-founder), IanOzsvald.com (my own blog, tech-savvy readers) and ProCasts.co.uk (this site) using the installed Google Analytics.

Monthly visitor counts are:

• ShowMeDo.com 100,000 (3 years+)
• IanOzsvald.com 1,500 (3 years+)
• ProCasts.co.uk 300 (6 months)

Counting the percentage of visitors who have Flash Player 9.0.115 or better we see:

• ShowMeDo.com 86%
• IanOzsvald.com 84%
• ProCasts.co.uk 96%

Using real-world sites that focus on a Western (US+European) tech-savvy audience we see that 85% of the majority of these visitors can see MP4-enabled content.  The other 15% probably can’t view the MP4 videos – they just see a link to the raw file or an error in Flash.  I’ll wager that many tech-focused sites see similar statistics – over 80% penetration but less than 90%.  If the tech-focused sites see less than 90%, how much worse does it get for general-folk-focused sites?

Possibly we follow jimb’s solution and support two versions of the video simultaneously.  Alternatively we export using mp4 and convert to flv until these percentages improve.

Perhaps someone else has an alternative solution?

CamTasia 6 doesn’t include FLV as an output option – many of us have used it consistently in CamTasia 5 with JW FLV Media Player and TechSmith’s decision to remove it has caused some headaches.

ffmpeg is a free tool that easily allows us to convert .mp4 screencasts into .flv screencasts.  Note that complex screencasts generate larger files – the mp4 example below is 10mb in size, the flv version with a similar visual quality is 20mb!

For testing I used my recent AppBeacon.com screencast.  The version on Justin’s site is exported from CamTasia 5 using FLV using these custom settings:

• 15 frames per second (fps)
• 10 frames between key frames
• Variable 2-pass bitrate control
• 2000 kbps max bit rate
• MP3 22kHz Mono 96kBits/sec audio

Get ffmpeg exes from tripp.arrozcru.org (via the official ffmpeg site).  I’m using 15625, the latest version (15815) crashed on my XP.  Extract the compressed .7z using 7-zip.

For simplicity, extrac ffmpeg.exe and copy it into your working video directory.  For long-term use add the ffmpeg directory into your path (else you have to copy ffmpeg.exe to your new project’s working directory each time).

The format to generate FLV output at the command line is:

ffmpeg -i INPUT -f flv -s WIDTHxHEIGHT -r 10fps -b 2000kbps -g 100
-acodec libmp3lame -ar 22050 -ab 48000 -ac 1 -y OUTPUT

The upper-case values need to be set by you, the rest of the values are good starting points for small files:

• INPUT is e.g. vid.avi or vid.mp4
• WIDTH is e.g. 640
• HEIGHT is e.g. 480
• OUTPUT is e.g. vid.flv

An example format to convert ‘vid.mp4′ into ‘vid.flv’ with a final size of 640×480 would be:

ffmpeg -i vid.avi -f flv -s 640x480 -r 10fps -b 2000kbps -g 100
-acodec libmp3lame -ar 22050 -ab 48000 -ac 1 -y vid.flv

The flags are:

• -f flv sets the output format to FLV
• -s 640×480 sets the output size, use e.g. 320×240 for a blog post
• -b 2000kbps sets the bitrate for the video, 2000 is fine for 640×480, use a smaller number if your output size is smaller
• -g 100 sets the gopsize (‘group of pictures’) to 100, this is ‘frames between a keyframe’, the keyframes are seek points and 100 is a large number (see below)
• -acodec libmp3lame gives mp3 which is required by flv videos
• -ar 22050 sets the audio rate to 22050Hz
• -ab 48000 sets the audio bitrate to 48kHz (i.e. high quality)
• -ac 1 sets the audio channels to 1 (i.e. mono)
• -r 10 fps set 10 frames-per-second, use a higher number for smoother animation (e.g. 25), larger numbers cause larger files
• -y is ‘force overwrite output file if exists’ (optional)

First I generated an mp4 version of the AppBeacon FLV file using CamTasia 6, the result is AppBeaconAutofps800kbps.mp4 (10mb).

Next I tried a variety of settings, finally settling on:

ffmpeg -i AppBeacon.mp4 -f flv -s 640x480 -r 15fps -b 700kbps -g 10
-acodec libmp3lame -ar 22050 -ab 48000 -ac 1 -y AppBeacon.flv

This generates AppBeacon15fps700kbps.flv (20mb) which has a similar size to the CamTasia 5 output and a similar quality.

Note the increased frame rate (15 fps), shorter gop size (10) and lower max bitrate (700kbps).

Now you have a simple, controllable way to convert CamTasia 6’s mp4 screencasts into flv files as generated by CamTasia 5.

Would you like a free eBook that covers all of this information (and more)? Our Little Book of Screencasting is in the works, to receive a notification when we release it send an email to: ebook_notify@procasts.co.uk