x265_encoder_encode函数

//pic_in是输入图像，pic_out是输出重构图像，pi_nal是编码返回的NAL单元个数，pp_nal是编码返回的NAL单元，这些单元在内存中是连续的。返回负值代表error，返回1表示输出一幅图像，返回0表示当前仍在编码不能输出或者编码器被flush过没有未输出帧了。
int x265_encoder_encode(x265_encoder *enc, x265_nal **pp_nal, uint32_t *pi_nal, x265_picture *pic_in, x265_picture *pic_out)
{
    if (!enc)
        return -1;

    Encoder *encoder = static_cast(enc);
    int numEncoded;

    // While flushing, we cannot return 0 until the entire stream is flushed
    do
    {
        numEncoded = encoder->encode(pic_in, pic_out);
    }
    while ((numEncoded == 0 && !pic_in && encoder->m_numDelayedPic && !encoder->m_latestParam->forceFlush) && !encoder->m_externalFlush);
    if (numEncoded)
        encoder->m_externalFlush = false;

    // do not allow reuse of these buffers for more than one picture. The
    // encoder now owns these analysisData buffers.
    if (pic_in)
    {
        pic_in->analysisData.wt = NULL;
        pic_in->analysisData.intraData = NULL;
        pic_in->analysisData.interData = NULL;
        pic_in->analysisData.distortionData = NULL;
    }

    if (pp_nal && numEncoded > 0 && encoder->m_outputCount >= encoder->m_latestParam->chunkStart)
    {
        *pp_nal = &encoder->m_nalList.m_nal[0];
        if (pi_nal) *pi_nal = encoder->m_nalList.m_numNal;
    }
    else if (pi_nal)
        *pi_nal = 0;

    if (numEncoded && encoder->m_param->csvLogLevel && encoder->m_outputCount >= encoder->m_latestParam->chunkStart)
        x265_csvlog_frame(encoder->m_param, pic_out);

    if (numEncoded < 0)
        encoder->m_aborted = true;

    return numEncoded;
}