BitCalc Pro

BitCalc Pro is a bitrate calculator app for Android.

BitCalc Pro allows you to quickly calculate duration, file size and bitrate for video encoding projects. Specify two of the parameters and BitCalc Pro will calculate the third. This allows you to calculate bitrate from duration and file size, calculate file size from duration and bitrate or calculate duration from file size and bitrate.

BitCalc Pro will also calculate bitrates for a specified resolution and frame rate for various "bits per pixel" values. This allows you determine a good starting point for a specific video if you are unsure what bitrate to try first. The results are calculated for a range of 0.09 bits per pixel through to 0.2 bits per pixel. These values are used by many well known media broadcasters.

It allows you to change the units used for time (seconds, minutes and hours), size (kilobyte, megabyte, gigabyte) and rate (kilobits per second, megabits per second, gigabits per second).

The latest version added a "Resolution" tab which calculates resolutions with a set aspect ratio where the X and Y dimensions are divisible by 4,8,16 or 32. These resolutions often make for more efficient encodes where the X dimension is a multiple of 4 (this varies with codec).

These calculations are vital when you are encoding video and need to determine what bitrate or file size you need to specify in your encoding settings.

In order to keep the app simple but versatile it deals with bitrate as a total. Remember that your total bitrate is a combination of your audio and video bitrates. BitCalc Pro calculates a total bitrate which you must split into video and audio as required. For example if you calculate a bitrate of 800kbs you must subtract your audio bitrate to determine your video bitrate.

Most video formats will also include some header information so the total file size generated by your encoding process may be slightly different to that shown in BitCalc Pro.

I would always recommend encoding a few versions of your video at various bitrates so you can compare the results as there is no right or wrong answer when it comes to selecting a bitrate. Ultimately you have to decide what is acceptable and what the audience of your video is going to accept.