showinfo: replace "CRC" by "checksum"

Indeed the Adler-32 checksum, which is computed by showinfo, is not
cyclic, so using the term "CRC" is wrong/confusing.

doc/filters.texi

@@ -1360,12 +1360,12 @@ Check also the documentation of the @code{AVPictureType} enum and of
 the @code{av_get_picture_type_char} function defined in
 @file{libavutil/avutil.h}.
 
-@item crc
-Adler-32 CRC of the input frame
+@item checksum
+Adler-32 checksum of all the planes of the input frame
 
-@item plane_crc
-Adler-32 CRC of each plane of the input frame, expressed in the form
-"[@var{crc0} @var{crc1} @var{crc2} @var{crc3}]"
+@item plane_checksum
+Adler-32 checksum of each plane of the input frame, expressed in the form
+"[@var{c0} @var{c1} @var{c2} @var{c3}]"
 @end table
 
 @section slicify

libavfilter/vf_showinfo.c

@@ -43,7 +43,7 @@ static void end_frame(AVFilterLink *inlink)
     AVFilterContext *ctx = inlink->dst;
     ShowInfoContext *showinfo = ctx->priv;
     AVFilterBufferRef *picref = inlink->cur_buf;
-    uint32_t plane_crc[4] = {0}, crc = 0;
+    uint32_t plane_checksum[4] = {0}, checksum = 0;
     int i, plane, vsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
 
     for (plane = 0; picref->data[plane] && plane < 4; plane++) {
@@ -52,8 +52,8 @@ static void end_frame(AVFilterLink *inlink)
         int h = plane == 1 || plane == 2 ? inlink->h >> vsub : inlink->h;
 
         for (i = 0; i < h; i++) {
-            plane_crc[plane] = av_adler32_update(plane_crc[plane], data, linesize);
-            crc = av_adler32_update(crc, data, linesize);
+            plane_checksum[plane] = av_adler32_update(plane_checksum[plane], data, linesize);
+            checksum = av_adler32_update(checksum, data, linesize);
             data += picref->linesize[plane];
         }
     }
@@ -61,7 +61,7 @@ static void end_frame(AVFilterLink *inlink)
     av_log(ctx, AV_LOG_INFO,
            "n:%d pts:%"PRId64" pts_time:%f pos:%"PRId64" "
            "fmt:%s sar:%d/%d s:%dx%d i:%c iskey:%d type:%c "
-           "crc:%u plane_crc:[%u %u %u %u]\n",
+           "checksum:%u plane_checksum:[%u %u %u %u]\n",
            showinfo->frame,
            picref->pts, picref ->pts * av_q2d(inlink->time_base), picref->pos,
            av_pix_fmt_descriptors[picref->format].name,
@@ -71,7 +71,7 @@ static void end_frame(AVFilterLink *inlink)
            picref->video->top_field_first ? 'T' : 'B',    /* Top / Bottom */
            picref->video->key_frame,
            av_get_picture_type_char(picref->video->pict_type),
-           crc, plane_crc[0], plane_crc[1], plane_crc[2], plane_crc[3]);
+           checksum, plane_checksum[0], plane_checksum[1], plane_checksum[2], plane_checksum[3]);
 
     showinfo->frame++;
     avfilter_end_frame(inlink->dst->outputs[0]);