This question has been asked before (see below) I'm also looking for some more up to date input.
http://stackoverflow.com/questions/1019109/what-transcoding-services-can-people-recommend
http://stackoverflow.com/questions/1695753/video-encoding-services
I'm working on an application that is going to need video/audio transcoding as well.
I initially thought I would have to implement by own service using something like FFMPEG but was concerned about licensing fees.
Then I saw that there were online services and thought problem solved. I'm just a 1 man isv startup so cost is pretty much all important at the moment. I've been pretty surprised by the cost differences between some of the main players:
encoding.com - priced by GB - $20 gets you 5GB of bandwith = (in + out) (supposedly - see below)
Heywatch - priced by minute - $0.10 for first 45 minutes of a video then $0.10 for each 15 minutes after that (note: 2 45 minute videos is $0.20 so the increasing price is per video rather than per minutes used).
Zencoder - priced by minute - $0.05 per minute on the most basic pay as you go plan.
So there are some huge apparent differences in pricing there.
e.g. for a 45 minute video: Heywatch = $0.10 ($0.20 for 2 pass); Zencoder = $2.25
(unless I'm really confused and missing something)
Harder to compare to encoding.com which is based on bandwidth. I'm initially doing audio/amr conversions to m4a (mobile phone stuff) and I calculated that encoding.com is going to be orders of magnitude cheaper than Zencoder.
However, I've been playing with encoding.com for the last couple of days and I'm pretty confused by how my encoding bandwidth is being eaten up.
I've been transcoding a 22KB audio/amr file to m4a (aac) and my encoding bandwidth goes up in increments of ~ 0.03 GB. i.e. 30 MB of bandwidth usage to encode a 22KB file. I'm either very confused or something is amuck! I've asked the encoding.com help desk to clarify that usage but so far they have not given me a satisfactory answer.
In terms of API, I'm coding my app in Ruby. I think the Zencoder web service api is using JSON, whereas the encoding.com api is XML.
I store my media in S3 and both Zencoder and encoding.com run on EC2 so it should be possible to minimize S3 bandwidth charges.
I've got a basic implementation of the encoding.com integration working. It's ok, but I'm having trouble getting encoding.com to write back to my S3 buckets using S3 query string authentication (it works ok for downloading stuff from S3 to encoding.com). Otherwise you have to give encoding.com write access to your buckets which I don't really want to do.
Hope this helps, and love to hear responses from anyone else who has used these services.
I'd like to go with Zencoder - I just seem to have a better feeling about them - but their service costs so much more!