jpeg_enc.c

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 *
 *  The actual buffers must be passed with mjpeg_encode_frame, this is
 *  to make it possible to call encode on the buffer provided by the
 *  codec in draw_frame.
 *  
 * The data is straightened out at the moment it is put in DCT
 * blocks, there are therefore no spurious memcopies involved */
/* Notice that w must be a multiple of 16 and h must be a multiple of 8 */
/* We produce YUV422 jpegs, the colors must be subsampled horizontally,
 * if the colors are also subsampled vertically, then this function
 * performs cheap upsampling (better solution will be: a DCT that is
 * optimized in the case that every two rows are the same) */
/* cu = 0 means 'No cheap upsampling'
 * cu = 1 means 'perform cheap upsampling' */
/* The encoder doesn't know anything about interlacing, the halve height
 * needs to be passed and the double rowstride. Which field gets encoded
 * is decided by what buffers are passed to mjpeg_encode_frame */
jpeg_enc_t *jpeg_enc_init(int w, int h, int y_psize, int y_rsize, 
		int u_psize, int u_rsize, int v_psize, int v_rsize,
		int cu, int q, int b) {
	jpeg_enc_t *j;
	int i = 0;
	mp_msg(MSGT_VO, MSGL_V, "JPEnc init: %dx%d %d %d %d %d %d %d\n",
			w, h, y_psize, y_rsize, u_psize, 
			u_rsize, v_psize, v_rsize);

	j = av_malloc(sizeof(jpeg_enc_t));
	if (j == NULL) return NULL;

	j->s = av_malloc(sizeof(MpegEncContext));
	memset(j->s,0x00,sizeof(MpegEncContext));
	if (j->s == NULL) {
		av_free(j);
		return NULL;
	}

	/* info on how to access the pixels */
	j->y_ps = y_psize; 
	j->u_ps = u_psize; 
	j->v_ps = v_psize;
	j->y_rs = y_rsize; 
	j->u_rs = u_rsize; 
	j->v_rs = v_rsize;

	j->s->width = w;
	j->s->height = h;
	j->s->qscale = q;

	j->s->out_format = FMT_MJPEG;
	j->s->intra_only = 1;
	j->s->encoding = 1;
	j->s->pict_type = I_TYPE;
	j->s->y_dc_scale = 8;
	j->s->c_dc_scale = 8;

	//FIXME j->s->mjpeg_write_tables = 1;
	j->s->mjpeg_vsample[0] = 1;
	j->s->mjpeg_vsample[1] = 1;
	j->s->mjpeg_vsample[2] = 1;
	j->s->mjpeg_hsample[0] = 2;
	j->s->mjpeg_hsample[1] = 1;
	j->s->mjpeg_hsample[2] = 1;

	j->cheap_upsample = cu;
	j->bw = b;

	/* if libavcodec is used by the decoder then we must not
	 * initialize again, but if it is not initialized then we must
	 * initialize it here. */
	if (!avcodec_inited) {
		/* we need to initialize libavcodec */
		avcodec_init();
		avcodec_register_all();
		avcodec_inited=1;
	}

	if (ff_mjpeg_encode_init(j->s) < 0) {
		av_free(j->s);
		av_free(j);
		return NULL;
	}

	/* alloc bogus avctx to keep MPV_common_init from segfaulting */
	j->s->avctx = calloc(sizeof(*j->s->avctx), 1);
	/* Set up to encode mjpeg */
	j->s->avctx->codec_id = CODEC_ID_MJPEG;

	/* make MPV_common_init allocate important buffers, like s->block */
	j->s->avctx->thread_count = 1;

	if (MPV_common_init(j->s) < 0) {
		av_free(j->s);
		av_free(j);
		return NULL;
	}

	/* correct the value for sc->mb_height */
	j->s->mb_height = j->s->height/8;
	j->s->mb_intra = 1;

	j->s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0];
	for (i = 1; i < 64; i++) 
		j->s->intra_matrix[i] = av_clip_uint8(
			(ff_mpeg1_default_intra_matrix[i]*j->s->qscale) >> 3);
	convert_matrix(j->s, j->s->q_intra_matrix, j->s->q_intra_matrix16, 
			j->s->intra_matrix, j->s->intra_quant_bias, 8, 8);
	return j;
}	

int jpeg_enc_frame(jpeg_enc_t *j, unsigned char *y_data, 
		unsigned char *u_data, unsigned char *v_data, char *bufr) {
	int i, k, mb_x, mb_y, overflow;
	short int *dest;
	unsigned char *source;
	/* initialize the buffer */

	init_put_bits(&j->s->pb, bufr, 1024*256);

	ff_mjpeg_encode_picture_header(j->s);

	j->s->header_bits = put_bits_count(&j->s->pb);

	j->s->last_dc[0] = 128; 
	j->s->last_dc[1] = 128; 
	j->s->last_dc[2] = 128;

	for (mb_y = 0; mb_y < j->s->mb_height; mb_y++) {
		for (mb_x = 0; mb_x < j->s->mb_width; mb_x++) {
			/* conversion 8 to 16 bit and filling of blocks
			 * must be mmx optimized */
			/* fill 2 Y macroblocks and one U and one V */
			source = mb_y * 8 * j->y_rs + 
				16 * j->y_ps * mb_x + y_data;
			dest = j->s->block[0];
			for (i = 0; i < 8; i++) {
				for (k = 0; k < 8; k++) {
					dest[k] = source[k*j->y_ps];
				}
				dest += 8;
				source += j->y_rs;
			}
			source = mb_y * 8 * j->y_rs + 
				(16*mb_x + 8)*j->y_ps + y_data;
			dest = j->s->block[1];
			for (i = 0; i < 8; i++) {
				for (k = 0; k < 8; k++) {
					dest[k] = source[k*j->y_ps];
				}
				dest += 8;
				source += j->y_rs;
			}
			if (!j->bw && j->cheap_upsample) {
				source = mb_y*4*j->u_rs + 
					8*mb_x*j->u_ps + u_data;
				dest = j->s->block[2];
				for (i = 0; i < 4; i++) {
					for (k = 0; k < 8; k++) {
						dest[k] = source[k*j->u_ps];
						dest[k+8] = source[k*j->u_ps];
					}
					dest += 16;
					source += j->u_rs;
				}
				source = mb_y*4*j->v_rs + 
					8*mb_x*j->v_ps + v_data;
				dest = j->s->block[3];
				for (i = 0; i < 4; i++) {
					for (k = 0; k < 8; k++) {
						dest[k] = source[k*j->v_ps];
						dest[k+8] = source[k*j->v_ps];
					}
					dest += 16;
					source += j->u_rs;
				}
			} else if (!j->bw && !j->cheap_upsample) {
				source = mb_y*8*j->u_rs + 
					8*mb_x*j->u_ps + u_data;
				dest = j->s->block[2];
				for (i = 0; i < 8; i++) {
					for (k = 0; k < 8; k++) 
						dest[k] = source[k*j->u_ps];
					dest += 8;
					source += j->u_rs;
				}
				source = mb_y*8*j->v_rs + 
					8*mb_x*j->v_ps + v_data;
				dest = j->s->block[3];
				for (i = 0; i < 8; i++) {
					for (k = 0; k < 8; k++) 
						dest[k] = source[k*j->v_ps];
					dest += 8;
					source += j->u_rs;
				}
			}
			emms_c(); /* is this really needed? */

			j->s->block_last_index[0] = 
				j->s->dct_quantize(j->s, j->s->block[0], 
						0, 8, &overflow);
			if (overflow) clip_coeffs(j->s, j->s->block[0], 
					j->s->block_last_index[0]);
			j->s->block_last_index[1] = 
				j->s->dct_quantize(j->s, j->s->block[1], 
						1, 8, &overflow);
			if (overflow) clip_coeffs(j->s, j->s->block[1], 
					j->s->block_last_index[1]);

			if (!j->bw) {
				j->s->block_last_index[4] =
					j->s->dct_quantize(j->s, j->s->block[2],
							4, 8, &overflow);
				if (overflow) clip_coeffs(j->s, j->s->block[2], 
						j->s->block_last_index[2]);
				j->s->block_last_index[5] =
					j->s->dct_quantize(j->s, j->s->block[3],
							5, 8, &overflow);
				if (overflow) clip_coeffs(j->s, j->s->block[3], 
						j->s->block_last_index[3]);
			}
			zr_mjpeg_encode_mb(j);
		}
	}
	emms_c();
	ff_mjpeg_encode_picture_trailer(j->s);
	flush_put_bits(&j->s->pb);	

	//FIXME
	//if (j->s->mjpeg_write_tables == 1)
	//	j->s->mjpeg_write_tables = 0;
	
	return pbBufPtr(&(j->s->pb)) - j->s->pb.buf;
}

void jpeg_enc_uninit(jpeg_enc_t *j) {
	ff_mjpeg_encode_close(j->s);
	av_free(j->s);
	av_free(j);
}

#if 0

#define		W	32	
#define		H	32

int quant_store[MBR+1][MBC+1];
unsigned char buf[W*H*3/2];
char code[256*1024];


main() {
	int i, size;
	FILE *fp;

	memset(buf, 0, W*H);
	memset(buf+W*H, 255, W*H/4);
	memset(buf+5*W*H/4, 0, W*H/4);
	mjpeg_encoder_init(W, H, 1, W, 1, W/2, 1, W/2, 1, 1, 0);

	size = mjpeg_encode_frame(buf, buf+W*H, buf+5*W*H/4, code);
	fp = fopen("test.jpg", "w");
	fwrite(code, 1, size, fp);
	fclose(fp);
}
#endif