android4.0 USB Camera Instance (five additions) JPG compression

In the end, we said a function that directly converts YUV to JPG, but the conversion is not successful. The original function is the research of yuv420 to JPG.

yuv420 the sequence of interlaced scanning is like this

YYYY

YYYY

Uvuv

And the yuv422 sequence of interlaced scans is like this.

Yu yv yu yv yu yv

So modify the function as follows

static int put_jpeg_yuv420p_memory (unsigned char *dest_image, unsigned char *input_image      , int width, int height) {int I, j, Jpeg_image_size; Jsamprow y[16],cb[16],cr[16]; Y[2][5] = Color sample of row 2 and pixel column 5;    (One plane) Jsamparray Data[3];    T[0][2][5] = Color Sample 0 of row 2 and column 5 struct jpeg_compress_struct cinfo;  struct Jpeg_error_mgr jerr;    Char *pbuf = Null;int Jpglen = 0;    Data[0] = y;    DATA[1] = CB;      DATA[2] = CR;  Cinfo.err = Jpeg_std_error (&jerr);    Errors get written to stderr jpeg_create_compress (&cinfo);    Cinfo.image_width = width;    Cinfo.image_height = height;    Cinfo.input_components = 3;      Jpeg_set_defaults (&cinfo);      Jpeg_set_colorspace (&cinfo, JCS_YCBCR);                  cinfo.raw_data_in = TRUE;       Supply downsampled Data cinfo.do_fancy_downsampling = FALSE;    Fix segfaulst with v7 cinfo.comp_info[0].h_samp_factor = 2;Cinfo.comp_info[0].v_samp_factor = 2;    Cinfo.comp_info[1].h_samp_factor = 1;    Cinfo.comp_info[1].v_samp_factor = 1;    Cinfo.comp_info[2].h_samp_factor = 1;      Cinfo.comp_info[2].v_samp_factor = 1;    Jpeg_set_quality (&cinfo, N, TRUE);      Cinfo.dct_method = Jdct_fastest;    Jpeg_mem_dest (&cinfo, &pbuf, &jpglen);      Data written to Mem jpeg_start_compress (&cinfo, TRUE); for (j = 0, J < height; J + = +) {for (i = 0; i < +; i++) {Y[i] = input_image + Width * (i + j)                ;                CB[I/2] = input_image + Width * height + width/2 * ((i + j)/2);            CR[I/2] = input_image + Width * height + width * HEIGHT/4 + width/2 * ((i + j)/2); if (i%2 = = 0) CB[I/2] = input_image + width * ((i + j)/2); ELSECR[I/2] = input_image + width * ((i + j)/        2);    } jpeg_write_raw_data (&cinfo, data, 16);    } jpeg_finish_compress (&cinfo); Jpeg_destroy_compress (&Amp;cinfo);    memcpy (Dest_image,pbuf,jpglen); if (pbuf) free (PBUF); return Jpglen;}

You can convert the yuv422 directly into JPG
The interface functions are modified as follows

Jniexport jint jnicall java_com_hclydao_usbcamera_fimcgzsd_writefile (jnienv * env, Jclass Obj,jbytearray Yuvdata, Jbytearray filename)//jintarray rgbdata{jbyte *ydata = (jbyte*) (*env)->getbytearrayelements (env, yuvdata, 0); jbyte *filedir = (jbyte*) (*env)->getbytearrayelements (env, filename, 0); FILE * outfile;  if (outfile = fopen (Filedir, "wb") = = = NULL) {    LOGE ("++++++++++++open%s failed\n", filedir);    return-1;  } unsigned char* DST = malloc (mwidth*mheight*3*sizeof (char)); int size = Put_jpeg_yuv420p_memory (Dst,ydata,mwidth, Mheight), fwrite (Dst,size,1,outfile), if (DST) free (DST), if (jpgdata) free (jpgdata), fclose (outfile);(*env), Releasebytearrayelements (env, Yuvdata, Ydata, 0);(*env)->releasebytearrayelements (env, filename, filedir, 0);}

Or do you want to study it in a quiet mind?