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我正在尝试使用 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？

解码图像

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
             //...
        }
}

为了找出哪一步错了，我在使用前保存了H264数据avcodec_decode_video2，解码后保存了YUV数据。我发现所有的H264数据都是正确的，而YUV数据是错误的，用P帧解码，I帧解码数据是ok的。这是我保存 YUV 数据的方法：

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;
    }
}
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