Read the original YUV data of the camera of the notebook, via LIBAV (FFMPEG encoded) __ encoded

The logic of the procedure is mainly divided into two parts:

1, through the video4linux2 to read the camera v4l2_pix_fmt_yuyv format of the original data

2. Convert the data in the V4L2_PIX_FMT_YUYV format into the YUV data in the av_pix_fmt_yuv422p format and store it in the avframe structure; send the avframe structure to the encoder;

Collect encoded H264 data stream, coexist in the file

Second, the main library used in the code:

1, through a call uvccapture-0.5 library (I directly changed the inside of the code), get the camera v4l2_pix_fmt_yuyv format data.

2, through the LIBAV code

Three, main code:

* * * * * main.cpp * * Created on:2014-3-2 * author:xy/#include <unistd.h> #include <stdio.h> #inc Lude <stdlib.h> #include <time.h> #include <linux/videodev2.h>//ffplay-f video4linux2-framerate 30-  Video_size hd720/dev/video0 #ifdef __cplusplus extern "C" {#endif #define __stdc_constant_macros #ifdef _stdint_h #undef _stdint_h #endif # include <stdint.h> #include "libavformat/avformat.h" #include "libavdevice/avdevice.h" # Include <libavutil/imgutils.h> #include <libavutil/opt.h> #ifdef __cplusplus} #endif//input device #include "v4l2u
	vc.h "int main () {//v4l2 val char *videodevice ="/dev/video0 "; int width = 640;
	320; int height = 480;
	240;
	int brightness = 0, contrast = 0, saturation = 0, gain = 0;
	int quality = 95;
	int format = V4L2_PIX_FMT_YUYV;
	struct Vdin *videoin;

	int grabmethod = 1;

	Video encoder init avcodec_register_all ();
	Avcodec *codec;
	Avcodeccontext *c = NULL;
	int I, ret, x, Y, got_output;FILE *f;
	Avframe *frame;
	Avpacket PKT;
	uint8_t endcode[] = {0, 0, 1, 0xb7};
	Char filename[] = "test.264";

	printf ("Encode video file%s\n", filename);
	/* Find the MPEG1 Video Encoder * * codec = Avcodec_find_encoder (av_codec_id_h264);
		if (!codec) {fprintf (stderr, "codec not found\n");
	Exit (1);
	} C = Avcodec_alloc_context3 (codec);
		if (!c) {fprintf (stderr, "Could not allocate video codec context\n");
	Exit (1);
	}/* Put sample parameters * * C->bit_rate = 400000; /* Resolution must be a multiple of two * * * c->width = width;
	352; C->height = height;
	288;
	/* Frames per second * * C->time_base = (avrational) {1,10/*25*/}; C->gop_size = 10; /* Emit one intra frame every ten frames/c->max_b_frames = 0; 1 c->pix_fmt = av_pix_fmt_yuv422p;

	V4L2 is this format av_pix_fmt_yuv420p;
	Av_opt_set (C->priv_data, "preset", "slow", 0); Av_opt_set (C->priv_data, "tune", "Zerolatency", 0); This allows LIBAV to not cache video frames/*********************************** There are two places that affect LIBAV is not cached encoded video frame, which is the impact of real-time: * 1, Av_opt_set (c->priv_data
			 , "Tune", "Zerolatency", 0); This is more important.
			 * 2, the parameter has C->max_b_frames = 1, if this frame is set to 0, there is no B frame, the code will be very fast. /* Open IT/if (Avcodec_open2 C,
		Codec, NULL) < 0) {fprintf (stderr, "could not open codec\n");
	Exit (1);
	} f = fopen (filename, "WB");
		if (!f) {fprintf (stderr, "could not open%s\n", filename);
	Exit (1);
	frame = Av_frame_alloc ();
		if (!frame) {fprintf (stderr, "Could not allocate video frame\n");
	Exit (1);
	} Frame->format = c->pix_fmt;
	Frame->width = c->width;

	Frame->height = c->height; /* The image can be allocated by any means and av_image_alloc () are * just the most convenient way if Av_malloc () to B
	E used * * ret = Av_image_alloc (Frame->data, Frame->linesize, C->width, C->height, C-&GT;PIX_FMT, 32); if (Ret < 0) {fprintf (stderr, "could not allocate raw picture buffer\n");
	Exit (1);
	}//v4l2 init videoin = (struct Vdin *) calloc (1, sizeof (struct vdin));

	if (Init_videoin (Videoin, (char *) videodevice, width, height, format, Grabmethod) < 0) exit (1);
	printf ("w:%d,h:%d\n", C->width, C->height);
	time_t TIMEP;
	TIMEP = time (NULL);
	printf ("%s\n", Asctime (Gmtime (&AMP;TIMEP));
		for (i = 0; i < i++) {//usleep (200000);
			The data format obtained from V4L2 is av_pix_fmt_yuv422p if (Uvcgrab (Videoin) < 0) {fprintf (stderr, "Error grabbing\n");
			CLOSE_V4L2 (Videoin);
			Free (videoin);
		Exit (1);
		} unsigned char *yuyv = videoin->framebuffer;
		Copy the data to the desired structure of the LIBAV av_init_packet (&AMP;PKT); Pkt.data = NULL;
		Packet data is allocated by the encoder pkt.size = 0;
		printf ("Debug!!!");
Fflush (stdout);  #if 0/* Prepare a dummy image *//* y * * (y = 0; y < c->height; y++) {for (x = 0; x < c->width; X + +) {Frame->data[0][y * frame->lINESIZE[0] + x] = x + y + i * 3; }/* Cb and Cr/for (y = 0, y < c->height/2; y++) {for (x = 0; x < c->width/2; x + +) {frame
				->data[1][y * Frame->linesize[1] + x] = 128 + y + i * 2;
			Frame->data[2][y * Frame->linesize[2] + x] = + + x + i * 5; } #else/* Prepare image */* y Cb Rb/* (y = 0; y < c->height; y++) {for (x = 0; x < c-> Width
			X + +) {Frame->data[0][y * frame->linesize[0] + x] = Yuyv[y * Frame->linesize[0] * 2 + 2 * x]; }/* Cb and Cr/for (y = 0, y < c->height; y++) {for (x = 0; x < c->width/2; x + +) {//fram
				E->data[0][y * Frame->linesize[0] + 2*x] = yuyv[y*frame->linesize[0]*4+4*x];
				Frame->data[0][y * Frame->linesize[0] + 2*x+1] = yuyv[y*frame->linesize[0]*4+4*x+2];
				Frame->data[1][y * Frame->linesize[1] + x] = Yuyv[y * frame->linesize[1] * 4 + 4 * x + 1]; Frame->data[2][y * Frame->lineSIZE[2] + x] = Yuyv[y * frame->linesize[2] * 4 + 4 * x + 3];

		}} #endif frame->pts = i;
		/* Encode the image */ret = Avcodec_encode_video2 (c, &AMP;PKT, frame, &got_output);
			if (Ret < 0) {fprintf (stderr, "Error encoding frame\n");
		Exit (1);
			} if (Got_output) {printf ("Write frame%3d (size=%5d) \ n", I, pkt.size);
			Fwrite (Pkt.data, 1, pkt.size, f);
		Av_free_packet (&AMP;PKT);

		//encoding}/* Get the delayed frames * * for (got_output = 1; got_output; i++) {fflush (stdout);
		ret = Avcodec_encode_video2 (c, &pkt, NULL, &got_output);
			if (Ret < 0) {fprintf (stderr, "Error encoding frame\n");
		Exit (1);
			} if (Got_output) {printf ("Write frame%3d (size=%5d) \ n", I, pkt.size);
			Fwrite (Pkt.data, 1, pkt.size, f);
		Av_free_packet (&AMP;PKT);
	} TIMEP = time (NULL);
	printf ("%s\n", Asctime (Gmtime (&AMP;TIMEP));
	/* Add sequence end code to have a real MPEG file */fwrite (Endcode, 1, sizeof (Endcode), f); Fclose (f);
	Avcodec_close (c);
	Av_free (c);
	Av_freep (&frame->data[0]);
	Av_frame_free (&frame);

	printf ("111\n");
Free (videoin);
 }

Friends who want to run the code can pass this article:

http://blog.csdn.net/xyyangkun/article/details/20456725

LIBAV Libraries used for compilation

Makefile in the process of modification:

libavdir=/home/xy/mywork/av/libav-2014-03-02

It is OK to specify the location of the LIBAV library.

The source of the code used to read the camera data:

http://staticwave.ca/source/uvccapture/uvccapture-0.5.tar.bz2

The project of the library is in the code:

http://download.csdn.net/detail/xyyangkun/6990791

The project has been uploaded to GitHub:

Https://github.com/xyyangkun/read_encoder_sender

Submitted version: 2E60986A438E731AA53CA7D54BC492C521E7B5BC