Using JMeter to simulate video viewing traffic

In my application some of the viewers would be viewing videos. We are using
HTML5 video tags to play videos in the application. To simulate this
functionality, I am running a test plan which makes HTTP requests to one
video for the number of users we want to simuate.

Now, the issue is, the test plan gives error "ERROR -
jmeter.threads.JMeterThread: Test failed! java.lang.OutOfMemoryError: Java
heap space" even for 10 users. The video size is 21MB. I doubt that test
plan is keeping the videos in the HEAP space of java. I have tried to
increase the heap space with no success. What is the best way to simulate
video traffic with JMeter? What should I change in my current approach.

Regards,
Ruchit