# How do you dramatically reduce the size of a video while keeping the quality as much as possible?

I'm very surprised how the video i have recorded with my camera are so heavy for small length (i have 4GB for only 20min). I've been trying compression softwares like handbrake, but it doesn't reduce the size enough IMO, and decreases the quality when i want to compress too much.

Just aside, you know those 700MB movies that last 1h and whose quality is still better than my video how come ? how do they do to compress ? do they use some professional expensive equipment ? or its just a matter of software ?

please help me to understand this, and to find out a way to compress my videos to the maximum.

• What size are you aiming for?
– Gyan
Commented Jul 30, 2016 at 10:13
• the smallest possible, i'm tempted to say: to have same ration as 700MB for 1h of video, hence around 250MB for mi video of 20min Commented Jul 30, 2016 at 10:14
• What settings did you try in Handbrake?
– Gyan
Commented Jul 30, 2016 at 10:15
• i followed this tutorial (youtube.com/watch?v=FB0ji_3Uees) that claimed to reduce the size by 90% but did't work for me i also tried similar tutorials.. Commented Jul 30, 2016 at 10:22
• Is it Full HD ?
– Gyan
Commented Jul 30, 2016 at 10:42

I'm not familiar with handbrake, but this is basically a math problem.

First, you have to decide on a codec. One of the 'best' codecs in regards to quality/filesize-ratio as well as device-compatibility is H.264, so I would recommed you go with that.

I've done a quick search on handbrake and it appears you can set the quality in two ways, either by choosing a Rate Factor (RF) or by setting an Average Bitrate (see screenshot, correct me if I'm wrong).

Source: Wikipedia

Since you want a ratio of 700 MB per 1 hour of video, let's do the math:

``````700 MB = 700 x 8 Mb =  5600 Mb
5600 Mbit / 3600 s = 1,56 Mb/s = 1560 kbps
``````

So to achieve this filesize average, set your Average Bitrate to 1560 kbps. This is quite low for HD video, so make sure to check the 2-pass encoding option, which will increase the quality at the cost of a longer encoding time (it does so by doing a first check or pass on the video as to how high a bitrate is needed for every part of it, so the encoder can better adjust the bitrate accordingly over the course of the video).

One final note, the video you linked recommends you change the audio bitrate to 128 kbps. This is a bad idea. Given that we are already using up 1,56 Mbit per second for the video, the few additional bits per second that are needed for the audio won't make much of a difference regarding the resulting file size. And 128 kbps will sound bad; we are much better at detecting flaws in audio than in video. I highly recommend you set the audio bitrate to at least 256 kbps.

• WaaW! thank you so much! for such detailed answer, i'm gonna try this! and revert to you,what is important in my computer to speed down this pocess ? the CPU or the RAM ? or even maybe the HDD ? Commented Jul 30, 2016 at 12:57
• A little bit of all. If you have a killer CPU but a slow HDD, the latter will be your performance bottleneck. Traditionally, video rendering only uses the CPU and no the GPU, but with the CUDA and OpenCL APIs, the GPU becomes a factor as well. I'm not sure if handbrake supports those libraries, maybe look that up on Google. RAM is also important, but a fast CPU and/or GPU (in case you're using the APIs named above) is most important. Read this for further reference. Commented Jul 30, 2016 at 13:03