As explained at high level about how video technology is being used to stream videos online, the basic question comes to mind is why not just download the media file and play it? We are downloading media files since very beginning of Internet and that’s happening very seamlessly. We can play downloaded media anytime we want without having Internet connection. Also we can easily transfer that media file to others through external hard drives and USB drives. Then why video technology guys have brought us the streaming technology?
Because streaming is the master factor which made possible so much things like OTT apps (e.g. Netflix), sports/events online live streaming, online TV and many more. Let’s see what makes streaming technology different than downloading.

Continuous Stream of Data

The basic difference between streaming and downloading is that streaming, as name suggests, is a continuous stream of chunks of file from server to client device, whereas downloading is simply copying whole file from server and saving it on client device. With this, streaming allows client device to start playback soon after receiving first few chunks. But for download, client has to wait for whole file to be downloaded and then can start playback (tough there are exceptions where client can start playback even before file gets completely downloaded).

Storing Media File on Device

For download, client device has to save whole file on disc and then only it can be played. But in case of streaming client device doesn’t save anything on disc still it can play media seamlessly. So client can play media files with longer durations without worrying about available disc space.

Network Data Consumption and Strength

Typically, network data consumption is same for both streaming and downloading media file. But with the advances in streaming technology, like Adaptive Bitrate (ABR) Streaming, client can play media file with really low data consumption. ABR also helps client maintain playback without any interruptions event if network is weak or fluctuating. This makes a large impact on clients connected over mobile network, where network data cost is still a considerable factor and fluctuations are more.
One more major difference is that streaming only downloads video data that is being watched (in streaming we can always stop advanced buffering of data), but in case of downloading all the video data has to be downloaded first, even if user wants to watch initial couple minutes.

Media Player

Client device should have media player that is compatible with respective playback method. That is, a media player which plays downloaded media file mostly can not play a stream of same media file. Both streaming and downloading has differences in playing given media and thus media player too.

There are more differences in streaming and downloading media files, which I will be explaining in more details in coming posts, but by then feel free to suggest more or ask questions about in comments.