.video-bitrate-calculator {
font-family: sans-serif;
max-width: 500px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
background-color: #f9f9f9;
}
.calculator-inputs .input-group {
margin-bottom: 15px;
}
.calculator-inputs label {
display: block;
margin-bottom: 5px;
font-weight: bold;
}
.calculator-inputs input[type="number"] {
width: 100%;
padding: 8px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box; /* Include padding and border in the element's total width and height */
}
.calculator-inputs button {
background-color: #4CAF50;
color: white;
padding: 10px 15px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
}
.calculator-inputs button:hover {
background-color: #45a049;
}
.calculator-result {
margin-top: 20px;
padding: 15px;
border: 1px solid #e0e0e0;
border-radius: 4px;
background-color: #fff;
font-size: 1.1em;
text-align: center;
}
function calculateVideoBitrate() {
var videoDurationMinutes = parseFloat(document.getElementById("videoDurationMinutes").value);
var videoDurationSeconds = parseFloat(document.getElementById("videoDurationSeconds").value);
var targetBitrateMbps = parseFloat(document.getElementById("targetBitrateMbps").value);
var audioBitrateKbps = parseFloat(document.getElementById("audioBitrateKbps").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(videoDurationMinutes) || isNaN(videoDurationSeconds) || isNaN(targetBitrateMbps) || isNaN(audioBitrateKbps)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
// Convert total duration to seconds
var totalDurationSeconds = (videoDurationMinutes * 60) + videoDurationSeconds;
// Convert target bitrate from Mbps to Kbps
var targetBitrateKbps = targetBitrateMbps * 1000;
// Calculate total bitrate (video + audio) in Kbps
var totalBitrateKbps = targetBitrateKbps + audioBitrateKbps;
// Calculate total file size in Kilobits
var fileSizeKilobits = totalBitrateKbps * totalDurationSeconds;
// Convert Kilobits to Megabits (for easier comparison with target bitrate)
var fileSizeMegabits = fileSizeKilobits / 1000;
// Convert Kilobits to Gigabytes (common file size unit)
// 1 Byte = 8 bits
// 1 Kilobyte (KB) = 1024 Bytes
// 1 Megabyte (MB) = 1024 KB
// 1 Gigabyte (GB) = 1024 MB
// So, 1 GB = 1024 * 1024 * 1024 Bytes = 8,589,934,592 bits
// To convert bits to GB: bits / 8,589,934,592
// Alternatively, convert Kilobits to MB, then MB to GB
// fileSizeKilobits / 1000 (to Kbps) / 1000 (to Mbps) / 1024 (to GB) is incorrect.
// Let's stick to the standard:
// Bits to Bytes: / 8
// Bytes to KB: / 1024
// KB to MB: / 1024
// MB to GB: / 1024
// So, Kilobits to GB = fileSizeKilobits / (1000 * 1024 * 1024 * 1024 / 1000) –> this is getting complicated.
// A more direct way:
// 1 Mbps = 1,000,000 bits per second
// 1 Kbps = 1,000 bits per second
// Total bits = (Video Bitrate in bits/sec + Audio Bitrate in bits/sec) * Total Duration in sec
// Total bits = (targetBitrateKbps * 1000 + audioBitrateKbps * 1000) * totalDurationSeconds
// Total bits = (targetBitrateMbps * 1000000 + audioBitrateKbps * 1000) * totalDurationSeconds
// Let's re-calculate using the most standard approach:
// 1. Calculate total duration in seconds: (videoDurationMinutes * 60) + videoDurationSeconds
// 2. Calculate total bitrate in bits per second: (targetBitrateMbps * 1,000,000) + (audioBitrateKbps * 1,000)
// 3. Calculate total file size in bits: total_bitrate_bps * total_duration_seconds
// 4. Convert bits to Gigabytes: total_file_size_bits / (1024 * 1024 * 1024)
// However, for simplicity and common usage, let's use the direct Kbps to GB conversion:
// 1 Megabyte (MB) = 1000 Kilobytes (KB) in data storage context often.
// 1 Gigabyte (GB) = 1000 Megabytes (MB) in data storage context often.
// But in networking and telecommunications, Mbps usually means 10^6 bits per second.
// And file sizes are often measured using powers of 1024 (KiB, MiB, GiB).
// Let's assume targetBitrateMbps is actual Megabits per second (10^6 bits/sec) and audioBitrateKbps is Kilobits per second (10^3 bits/sec).
var totalDurationSecondsCorrect = (videoDurationMinutes * 60) + videoDurationSeconds;
var videoBitrateBps = targetBitrateMbps * 1000000; // Mbps to bps
var audioBitrateBps = audioBitrateKbps * 1000; // Kbps to bps
var totalBitrateBps = videoBitrateBps + audioBitrateBps;
var fileSizeBits = totalBitrateBps * totalDurationSecondsCorrect;
// Convert bits to Gigabytes (GiB, using 1024 for conversion)
var fileSizeGiB = fileSizeBits / (1024 * 1024 * 1024);
// Convert bits to Megabytes (MiB, using 1024 for conversion)
var fileSizeMiB = fileSizeBits / (1024 * 1024);
resultDiv.innerHTML = "Estimated File Size: " + fileSizeGiB.toFixed(2) + " GiB (Gigibytes) " +
"Estimated File Size: " + fileSizeMiB.toFixed(2) + " MiB (Mebibytes)";
}
Understanding Video Bitrate and File Size Calculation
When you're working with video, whether you're encoding for streaming, archival, or editing, understanding bitrate is crucial. Bitrate is the amount of data used per unit of time to encode video and audio. It's typically measured in bits per second (bps), kilobits per second (Kbps), or megabits per second (Mbps).
What is Bitrate?
Think of bitrate as the "thickness" of your video stream. A higher bitrate means more data is being used to represent the video and audio information, leading to potentially higher quality but also larger file sizes. Conversely, a lower bitrate uses less data, resulting in smaller files but possibly sacrificing quality, especially in scenes with a lot of motion or detail.
- Video Bitrate: This is the primary component of your total bitrate and determines the quality of the visual information.
- Audio Bitrate: This determines the quality of the sound. It's usually much lower than the video bitrate.
Why Calculate File Size?
Knowing how to estimate the file size of your video is essential for several reasons:
- Storage Management: To ensure you have enough space on hard drives, servers, or cloud storage.
- Bandwidth Planning: For streaming services, it helps determine the required internet speed for viewers and manage data consumption.
- Delivery Time: Estimating how long it will take to upload or download a video file.
- Cost Estimation: For cloud storage or data transfer services that charge based on volume.
How the Calculator Works
This calculator uses a standard formula to estimate the video file size based on its duration, the target video bitrate, and the audio bitrate:
- Total Duration in Seconds: The calculator first converts your input duration (in minutes and seconds) into a single value representing the total length of the video in seconds.
- Total Bitrate in Bits Per Second (bps): It then combines the video and audio bitrates. The target video bitrate is typically given in Megabits per second (Mbps) and is converted to bits per second (1 Mbps = 1,000,000 bps). The audio bitrate, usually in Kilobits per second (Kbps), is converted to bits per second (1 Kbps = 1,000 bps). These are summed to get the total bitrate in bits per second.
- Total File Size in Bits: The total bitrate in bits per second is multiplied by the total duration in seconds to find the total amount of data in bits.
- Conversion to Gigabytes/Mebibytes: Finally, the total number of bits is converted into more human-readable units like Gigabytes (GB) or Mebibytes (MiB). For practical file size calculations, we often use powers of 1024 (e.g., 1 GiB = 1024 MiB, 1 MiB = 1024 KiB). This calculator provides the size in GiB (Gigibytes) and MiB (Mebibytes).
Example Calculation
Let's say you have a video that is 12 minutes and 30 seconds long. You want to encode it with a target video bitrate of 8 Mbps and an audio bitrate of 192 Kbps.
- Duration: 12 minutes * 60 seconds/minute + 30 seconds = 720 + 30 = 750 seconds.
- Video Bitrate: 8 Mbps * 1,000,000 bps/Mbps = 8,000,000 bps.
- Audio Bitrate: 192 Kbps * 1,000 bps/Kbps = 192,000 bps.
- Total Bitrate: 8,000,000 bps + 192,000 bps = 8,192,000 bps.
- Total File Size (bits): 8,192,000 bps * 750 seconds = 6,144,000,000 bits.
- Total File Size (GiB): 6,144,000,000 bits / (1024 * 1024 * 1024) ≈ 5.72 GiB.
- Total File Size (MiB): 6,144,000,000 bits / (1024 * 1024) ≈ 5859.38 MiB.
Using our calculator with inputs: Video Duration (Minutes) = 12, Video Duration (Seconds) = 30, Target Bitrate (Mbps) = 8, Audio Bitrate (Kbps) = 192, you would get an estimated file size of approximately 5.72 GiB.