StreamSourceMpeg.cpp

#include "Headers.h"
#include "StreamSourceMpeg.h"

CStreamSourceMpegFrameTemplate::CStreamSourceMpegFrameTemplate(
    EFrameType  type,
    __uint32    size,
    char        anchorP,
    char        anchorB
    )
{
    this->type = type;
    this->size = size;
    this->anchorP = anchorP;
    this->anchorB = anchorB;
}

CStreamSourceMpeg::CStreamSourceMpeg(
    CChannel*   channel,
    __byte      gopDistanceItoI,
    __byte      gopDistanceItoP,
    __byte      segmentSize
    ) : CStreamSource(channel)
{
    assert(gopDistanceItoI > 0);
    assert(gopDistanceItoP > 0);
    assert(gopDistanceItoI >= gopDistanceItoP);

    this->gopDistanceItoI = gopDistanceItoI;
    this->gopDistanceItoP = gopDistanceItoP;
    this->segmentSize = segmentSize;

    // Generate frame template
    this->gopTemplate = new CStreamSourceMpegFrameTemplate[this->gopDistanceItoI];

    // I frame
    this->gopTemplate[0] = CStreamSourceMpegFrameTemplate(
        FRAME_I,
        (__uint32)ceil(this->channel->Bw()/this->channel->Fps()),
        0,
        0);

    // P frames
    for(char indexP = this->gopDistanceItoP; indexP < this->gopDistanceItoI; indexP += this->gopDistanceItoP)
    {
        this->gopTemplate[indexP] = CStreamSourceMpegFrameTemplate(
            FRAME_P,
            (__uint32)ceil(this->channel->Bw()/this->channel->Fps()),
            -((char)this->gopDistanceItoP), // Previous anchor
            0);
    }

    // B frames
    for(char indexP = 0; indexP < this->gopDistanceItoI; indexP += this->gopDistanceItoP)
    {
        for(char indexB = indexP + 1; indexB < indexP + this->gopDistanceItoP; indexB++)
        {
            this->gopTemplate[indexB] = CStreamSourceMpegFrameTemplate(
                FRAME_B,
                (__uint32)ceil(this->channel->Bw()/this->channel->Fps()),
                -((char)(indexB - indexP)), // Previous anchor
                (indexP + this->gopDistanceItoP - indexB) // Next anchor
                );
        }
    }
}

CStreamSourceMpeg::~CStreamSourceMpeg()
{
    delete[] this->gopTemplate;
}

CStreamFrame CStreamSourceMpeg::Fetch(__uint32 index)
{
    // Generate frame

    // Calculate GOP index
    __uint32 idx = index % this->gopDistanceItoI;

    return CStreamFrame(
        this->channel->Id(),
        this->gopTemplate[idx].type,
        index,
        this->gopTemplate[idx].anchorP,
        this->gopTemplate[idx].anchorB,
        this->gopTemplate[idx].size,
        index / this->segmentSize,
        index % this->segmentSize,
        this->segmentSize
        );
}