Tuning Guide

Depending on the device and network speeds, different media capture and encode settings result in a better user experience. This guide serves as our best recommendations, and is going to be updated periodically as new test results emerge.

Platforms

iOS Minimum and Recommended Requirements

Minimum for two-way, or three-way, video chat - A7 processor or better:

iPhone 5S or newer
iPad Air
iPad Mini second generation or newer

Recommended for three-way video chat or two-way HD video chat - A8 processor or better:

iPhone 6 or newer
iPad Air 2 or newer

iOS Video Capture Recommendations

If the chipset is A7, set the video preset to AVCaptureSessionPresetLow.

Otherwise, set the video preset to AVCaptureSessionPreset640x480.

// https://github.com/fahrulazmi/UIDeviceHardware/blob/master/UIDeviceHardware.m


- (NSString *) platform
{
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *machine = malloc(size);
    sysctlbyname("hw.machine", machine, &size, NULL, 0);
    NSString *platform = [NSString stringWithUTF8String:machine];
    free(machine);
    return platform;
}

- (bool)isA5Chipset
{
    NSString *platform = [self platform];
    return ([platform startsWithValue:@"iPhone4,"] || // iPhone 4S
            [platform startsWithValue:@"iPad2,"] ||   // iPad 2 and Mini
            [platform isEqualToString:@"iPod5,1"]);   // iPod 5
}

- (bool)isA5XChipset
{
    NSString *platform = [self platform];
    return ([platform isEqualToString:@"iPad3,1"] || // iPad 3
            [platform isEqualToString:@"iPad3,2"] ||
            [platform isEqualToString:@"iPad3,3"]);
}

Android Minimum and Recommended Requirements

Recommended for two-way video chat - 1.4GHz dual-core or better:

Google Nexus 4
Samsung Galaxy S3

Minimum for three-way video - 1.6GHz quad-core or better:

Google Nexus 5
Samsung Galaxy S4

Recommended for three-way video chat or two-way HD video chat - 2.4GHz quad-core processor or better:

Google Nexus 6
Samsung Galaxy S5

Android Video Capture Recommendations

If the CPU core count is 1, set the video width, height, and frame-rate to 320, 240, and 15.

If the CPU core count is 2, set the video width, height, and frame-rate to 320, 240, and 30.

Otherwise, set the video width, height, and frame-rate to 640, 480, and 30.

// http://stackoverflow.com/questions/30119604/how-to-get-the-number-of-cores-of-an-android-device
private int getNumberOfCores() {
    if(Build.VERSION.SDK_INT >= 17) {
        return Runtime.getRuntime().availableProcessors()
    }
    else {
       // Use saurabh64's answer
       return getNumCoresOldPhones();
    }
}

/**
 * Gets the number of cores available in this device, across all processors.
 * Requires: Ability to peruse the filesystem at "/sys/devices/system/cpu"
 * @return The number of cores, or 1 if failed to get result
 */
private int getNumCoresOldPhones() {
    //Private Class to display only CPU devices in the directory listing
    class CpuFilter implements FileFilter {
        @Override
        public boolean accept(File pathname) {
            //Check if filename is "cpu", followed by a single digit number
            if(Pattern.matches("cpu[0-9]+", pathname.getName())) {
                return true;
            }
            return false;
        }      
    }

    try {
        //Get directory containing CPU info
        File dir = new File("/sys/devices/system/cpu/");
        //Filter to only list the devices we care about
        File[] files = dir.listFiles(new CpuFilter());
        //Return the number of cores (virtual CPU devices)
        return files.length;
    } catch(Exception e) {
        //Default to return 1 core
        return 1;
    }
}

Networks

2G / GPRS

Average download speed: 50kbps
Average upload speed: 25kbps

A connection is generally not possible.

2G / EDGE

Average download speed: 100kbps
Average upload speed: 50kbps

An audio-only connection may be possible.

Recommended Opus encoder bitrate: 32kbps

3G / Basic

Average download speed: 400kbps
Average upload speed: 300kbps

An audio-only connection should be possible.

Recommended Opus encoder bitrate: 32kbps

3G / HSPA

Average download speed: 1.5mbps
Average upload speed: 0.75mbps

A low-quality audio/video connection should be possible.

Recommended Opus encoder bitrate: 32kbps
Recommended VP8/H.264 encoder bitrate: 256kbps

3G / HSPA+

Average download speed: 4mbps
Average upload speed: 1.5mbps

An audio/video connection should be possible.

Recommended Opus encoder bitrate: 48kbps
Recommended VP8/H.264 encoder bitrate: 384kbps

3G / DC-HSPA+

Average download speed: 8mbps
Average upload speed: 3mbps

A high-quality audio/video connection should be possible.

Recommended Opus encoder bitrate: 48kbps
Recommended VP8/H.264 encoder bitrate: 512kbps

4G / LTE

Average download speed: 15mbps
Average upload speed: 7.5mbps

A high-quality audio/video connection should be possible.

Recommended Opus encoder bitrate: 64kbps
Recommended VP8/H.264 encoder bitrate: 512kbps