If there are multiple fbs, whether the specified frame can be retrieved from the cache

[cainiaoyizhou]

I was using the esp32s3, using the ov2640 to get a JPEG stream and send it to the 4G module through the serial port. Then I set fb_count to 2, xclk_freq_hz to 40 million and running steadily, and pushed the frame time into 40ms(25 FPS). But uart also takes time to send, if a single thread runs then it will be less than 25 frames, multi-threaded running requires that I must first copy the obtained frame to another piece of ram, and then get the next frame and send the last frame. But since fb_cont is 2, that is, there are two frames in the buffer, and esp_camera_fb_get only changes one frame at a time, can I send the previous frame when I get a new frame, so that I can run uninterrupted

我在用esp32s3当中转，用ov2640获取JPEG流在通过串口发到4G模块上。然后我把fb_count设为2，xclk_freq_hz开到了4千万并稳定运行，一帧的时间压进了40ms(也就是25fps)。但是uart发送也需要时间，如果单线程运行那么就达不到25帧，多线程运行就要求我必须把获取到的帧先复制到另一块ram，然后获取下一帧同时把上一帧发出去。但是既然fb_cont是2，也就是缓冲区本来就有两帧，一次esp_camera_fb_get又只改一帧，那我是不是可以趁获取新帧的时候把上一帧发出去，这样就可以不间断运行了