H264使用ffmpeg解码，解码图像中有奇怪的点

Question

我尝试使用FFmpeg将H264流解码为YUV数据，然后通过LibYUV将YUV数据转换为RGB数据，最后绘制它。但是出现了一些奇怪的点（点）。如何解决？

Decoded Image

av_init_packet(&m_avpkt);
int cur_size;
uint8_t *cur_ptr;
while (true)
{
    memset(outSampleBuffer, 0, IMAGE_BUFFER);
    long ret = m_pInputPortInfo->pPacketPool->receivePacket(outSampleBuffer, info);
    cur_size = info.size;
    cur_ptr = (uint8_t *)outSampleBuffer;

    if (m_de_context == NULL)
        continue;

    while (cur_size > 0)
    {
        int len = av_parser_parse2(
            pCodecParser, m_de_context,
            &m_avpkt.data, &m_avpkt.size,
            cur_ptr, cur_size,
            AV_NOPTS_VALUE, AV_NOPTS_VALUE, AV_NOPTS_VALUE);

        cur_ptr += len;
        cur_size -= len;

        if (m_avpkt.size == 0)
            continue;
        int got_picture = 0;
        int iOutLen = avcodec_decode_video2(m_de_context, m_de_frame, &got_picture, &m_avpkt);
        if (got_picture != 0)
        {
             //YUV to RGB
             //...
        }
}

为了找出哪个步骤错误，我在使用avcodec_decode_video2之前保存H264数据，然后在解码后保存YUV数据。我发现所有H264数据都是正确的并且YUV数据是错误的，这是由P帧解码的，I帧解码数据是可以的。以下是我如何保存YUV数据：

int got_picture = 0;
int iOutLen = avcodec_decode_video2(m_de_context, m_de_frame, &got_picture, &m_avpkt);
if (got_picture != 0)
{
    if (m_de_frame->format == AVPixelFormat::AV_PIX_FMT_YUV420P)
    {
        int y = m_de_frame->width*m_de_frame->height;
        int u = y / 4;
        int v = y / 4;

        uint8_t* y_ptr = m_de_frame->data[0];
        uint8_t* u_ptr = m_de_frame->data[1];
        uint8_t* v_ptr = m_de_frame->data[2];

        int yuvbufsize = y + u + v;
        char *buf = new char[yuvbufsize];
        memcpy(buf, y_ptr, y);
        memcpy(buf + y, u_ptr, u);
        memcpy(buf + y+u, v_ptr, v);

        static int count = 0;
        char yuvimgPath[MAX_PATH] = { 0 };
        sprintf(yuvimgPath, "d:\\images\\de_%d.yuv", count);

        FILE *fp1 = fopen(yuvimgPath, "wb");
        fwrite(buf, 1, yuvbufsize, fp1);
        fclose(fp1);
        count++;

        delete[]buf;
    }
}