function frameType = SSC(~, nextFrameT, prevFrameType)
%Implementation of the SSC step
%   Usage frameType = SSC(frameT, nextFrameT, prevFrameType), where:
%       Inputs
%       - frameT is a frame in the time domain, containing both channels of
%           the audio stored in an array of dimensions 2048X2
%       - nextFrameT is the next frame in the time domain, containing both
%       channels of the audio stored in an array of dimensions 2048X2
%       - prevFrameType is the type of the previous frame in string
%       representation, can be one of "OLS" (ONLY_LONG_SEQUENCE), "LSS"
%       (LONG_START_SEQUENCE), "ESH" (EIGHT_SHORT_SEQUENCE), "LPS"
%       (LONG_STOP_SEQUENCE)
%
%       Output
%       - frameType is the type of the current frame in string
%       representation, can be one of "OLS" (ONLY_LONG_SEQUENCE), "LSS"
%       (LONG_START_SEQUENCE), "ESH" (EIGHT_SHORT_SEQUENCE), "LPS"
%       (LONG_STOP_SEQUENCE)

    % Examines the cases where the determination of the type of the next
    % frame isn't needed for
    if strcmp(prevFrameType, 'LSS')
        frameType = 'ESH';
        return;
    elseif strcmp(prevFrameType, 'LPS')
        frameType = 'OLS';
        return;
    end

    % Determines the type of the next frame
    % Filters frame
    nextFrameT = filter([0.7548, -0.7548], [1, -0.5095], nextFrameT, [], 2);

    channelFrameType = {'OLS', 'OLS'};

    for channel = 1:2
        % Calculates sub-frame energy estimation
        [subFrames, ~] = buffer(nextFrameT(449:end-448, channel), 256, 128, 'nodelay');
        energyEstimations = sum(subFrames.^2, 1);

        % Calculates the ratio of the sub-frame energy to the average energy of
        % the previous sub-frames
        nextIsESH = 0;
        for subFrameIndex = 1:8
            energyRatio = energyEstimations(subFrameIndex) / ...
                mean(energyEstimations(1:subFrameIndex-1));

            if (energyEstimations(subFrameIndex) > 10^(-3)) && (energyRatio > 10)
                nextIsESH = 1;
                break;
            end
        end

        if nextIsESH == 1
            if strcmp(prevFrameType, 'ESH')
                % This frame of this channel is an EIGHT_SHORT_SEQUENCE type
                % frame. This means the frames of both channels will be encoded
                % as EIGHT_SHORT_SEQUENCE type frames.
                frameType = 'ESH';
                return;
            elseif strcmp(prevFrameType, 'OLS')
                channelFrameType{channel} = 'LSS';
            end
        else
            if strcmp(prevFrameType, 'ESH')
                channelFrameType{channel} = 'LPS';
            elseif strcmp(prevFrameType, 'OLS')
                channelFrameType{channel} = 'OLS';
            end
        end
    end

    if strcmp(channelFrameType{1}, 'OLS')
        frameType = channelFrameType{2};
    elseif strcmp(channelFrameType{2}, 'OLS')
        frameType = channelFrameType{1};
    elseif strcmp(channelFrameType{1}, channelFrameType{2})
        frameType = channelFrameType{1};
    else
        frameType = 'ESH';
    end
end