ref: b858f5cc47844bef342bf71de98675027e6570aa
dir: /examples/decode_to_md5.txt/
@TEMPLATE decoder_tmpl.c Frame-by-frame MD5 Checksum =========================== ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION This example builds upon the simple decoder loop to show how checksums of the decoded output can be generated. These are used for validating decoder implementations against the reference implementation, for example. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION MD5 algorithm ------------- The Message-Digest 5 (MD5) is a well known hash function. We have provided an implementation derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm for your use. Our implmentation only changes the interface of this reference code. You must include the `md5_utils.h` header for access to these functions. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_INCLUDES #include "md5_utils.h" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_INCLUDES Processing The Decoded Data --------------------------- Each row of the image is passed to the MD5 accumulator. First the Y plane is processed, then U, then V. It is important to honor the image's `stride` values. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PROCESS_DX unsigned char md5_sum[16]; md5_ctx_t md5; int i; md5_init(&md5); for(plane=0; plane < 3; plane++) { unsigned char *buf =img->planes[plane]; for(y=0; y<img->d_h >> (plane?1:0); y++) { md5_update(&md5, buf, img->d_w >> (plane?1:0)); buf += img->stride[plane]; } } md5_finalize(&md5, md5_sum); for(i=0; i<16; i++) fprintf(outfile, "%02x",md5_sum[i]); fprintf(outfile, " img-%dx%d-%04d.i420\n", img->d_w, img->d_h, frame_cnt); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PROCESS_DX