diff --git a/include/log/event_tag_map.h b/include/log/event_tag_map.h
index 69774ba..22e62ec 100644
--- a/include/log/event_tag_map.h
+++ b/include/log/event_tag_map.h
@@ -48,7 +48,15 @@
  * Look up a tag by index.  Returns the tag string & string length, or NULL if
  * not found.  Returned string is not guaranteed to be nul terminated.
  */
-const char* android_lookupEventTag_len(const EventTagMap* map, size_t* len, unsigned int tag);
+const char* android_lookupEventTag_len(const EventTagMap* map,
+                                       size_t* len, unsigned int tag);
+
+/*
+ * Look up a format by index. Returns the format string & string length,
+ * or NULL if not found. Returned string is not guaranteed to be nul terminated.
+ */
+const char* android_lookupEventFormat_len(const EventTagMap* map,
+                                          size_t* len, unsigned int tag);
 
 #ifdef __cplusplus
 }
diff --git a/include/log/logprint.h b/include/log/logprint.h
index 493f9f8..3509e7f 100644
--- a/include/log/logprint.h
+++ b/include/log/logprint.h
@@ -46,6 +46,7 @@
     FORMAT_MODIFIER_EPOCH,     /* Print time as seconds since Jan 1 1970 */
     FORMAT_MODIFIER_MONOTONIC, /* Print cpu time as seconds since start */
     FORMAT_MODIFIER_UID,       /* Adds uid */
+    FORMAT_MODIFIER_DESCRIPT,  /* Adds descriptive */
 } AndroidLogPrintFormat;
 
 typedef struct AndroidLogFormat_t AndroidLogFormat;
diff --git a/liblog/event_tag_map.c b/liblog/event_tag_map.c
index 0e5a281..f9cad99 100644
--- a/liblog/event_tag_map.c
+++ b/liblog/event_tag_map.c
@@ -38,6 +38,8 @@
     uint32_t tagIndex;
     char*    tagStr;
     size_t   tagLen;
+    char*    fmtStr;
+    size_t   fmtLen;
 } EventTag;
 
 /*
@@ -176,6 +178,39 @@
     return NULL;
 }
 
+/*
+ * Look up an entry in the map.
+ *
+ * The entries are sorted by tag number, so we can do a binary search.
+ */
+LIBLOG_ABI_PUBLIC const char* android_lookupEventFormat_len(
+    const EventTagMap* map, size_t *len, unsigned int tag)
+{
+    int lo = 0;
+    int hi = map->numTags - 1;
+
+    while (lo <= hi) {
+        int mid = (lo + hi) / 2;
+        int cmp = map->tagArray[mid].tagIndex - tag;
+
+        if (cmp < 0) {
+            /* tag is bigger */
+            lo = mid + 1;
+        } else if (cmp > 0) {
+            /* tag is smaller */
+            hi = mid - 1;
+        } else {
+            /* found */
+            if (len) *len = map->tagArray[mid].fmtLen;
+            return map->tagArray[mid].fmtStr;
+        }
+    }
+
+    errno = ENOENT;
+    if (len) *len = 0;
+    return NULL;
+}
+
 LIBLOG_ABI_PUBLIC const char* android_lookupEventTag(const EventTagMap* map,
                                                      unsigned int tag)
 {
@@ -364,17 +399,21 @@
     }
     tag->tagLen = cp - tag->tagStr;
 
-    if (isspace(*cp)) {
-        /* just ignore the rest of the line till \n
-        TODO: read the tag description that follows the tag name
-        */
-        while (*cp != '\n') ++cp;
-    } else {
+    if (!isspace(*cp)) {
         fprintf(stderr, "%s: invalid tag chars on line %d\n", OUT_TAG, lineNum);
         errno = EINVAL;
         return -1;
     }
 
+    while (isspace(*cp) && (*cp != '\n')) ++cp;
+    if (*cp != '#') {
+        tag->fmtStr = cp;
+        while ((*cp != '\n') && (*cp != '#')) ++cp;
+        while ((cp > tag->fmtStr) && isspace(*(cp - 1))) --cp;
+        tag->fmtLen = cp - tag->fmtStr;
+    }
+
+    while (*cp != '\n') ++cp;
     *pData = cp;
 
     return 0;
@@ -406,12 +445,14 @@
     for (i = 1; i < map->numTags; i++) {
         if (map->tagArray[i].tagIndex == map->tagArray[i - 1].tagIndex) {
             fprintf(stderr,
-                "%s: duplicate tag entries (%" PRIu32 ":%.*s and %" PRIu32 ":%.*s)\n",
+                "%s: duplicate tag entries (%" PRIu32 ":%.*s:%.*s and %" PRIu32 ":%.*s:%.*s)\n",
                 OUT_TAG,
-                map->tagArray[i].tagIndex, (int)map->tagArray[i].tagLen,
-                map->tagArray[i].tagStr,
-                map->tagArray[i - 1].tagIndex, (int)map->tagArray[i - 1].tagLen,
-                map->tagArray[i - 1].tagStr);
+                map->tagArray[i].tagIndex,
+                (int)map->tagArray[i].tagLen, map->tagArray[i].tagStr,
+                (int)map->tagArray[i].fmtLen, map->tagArray[i].fmtStr,
+                map->tagArray[i - 1].tagIndex,
+                (int)map->tagArray[i - 1].tagLen, map->tagArray[i - 1].fmtStr,
+                (int)map->tagArray[i - 1].fmtLen, map->tagArray[i - 1].fmtStr);
             errno = EMLINK;
             return -1;
         }
diff --git a/liblog/logprint.c b/liblog/logprint.c
index 1ff7136..fb942a1 100644
--- a/liblog/logprint.c
+++ b/liblog/logprint.c
@@ -21,13 +21,13 @@
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <pwd.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <inttypes.h>
 #include <sys/param.h>
 #include <sys/types.h>
 
@@ -58,9 +58,16 @@
     bool epoch_output;
     bool monotonic_output;
     bool uid_output;
+    bool descriptive_output;
 };
 
 /*
+ * API issues prevent us from exposing "descriptive" in AndroidLogFormat_t
+ * during android_log_processBinaryLogBuffer(), so we break layering.
+ */
+static bool descriptive_output = false;
+
+/*
  *  gnome-terminal color tags
  *    See http://misc.flogisoft.com/bash/tip_colors_and_formatting
  *    for ideas on how to set the forground color of the text for xterm.
@@ -209,6 +216,8 @@
     p_ret->epoch_output = false;
     p_ret->monotonic_output = android_log_clockid() == CLOCK_MONOTONIC;
     p_ret->uid_output = false;
+    p_ret->descriptive_output = false;
+    descriptive_output = false;
 
     return p_ret;
 }
@@ -267,6 +276,10 @@
     case FORMAT_MODIFIER_UID:
         p_format->uid_output = true;
         return 0;
+    case FORMAT_MODIFIER_DESCRIPT:
+        p_format->descriptive_output = true;
+        descriptive_output = true;
+        return 0;
     default:
         break;
     }
@@ -294,6 +307,7 @@
     else if (strcmp(formatString, "threadtime") == 0) format = FORMAT_THREADTIME;
     else if (strcmp(formatString, "long") == 0) format = FORMAT_LONG;
     else if (strcmp(formatString, "color") == 0) format = FORMAT_MODIFIER_COLOR;
+    else if (strcmp(formatString, "colour") == 0) format = FORMAT_MODIFIER_COLOR;
     else if (strcmp(formatString, "usec") == 0) format = FORMAT_MODIFIER_TIME_USEC;
     else if (strcmp(formatString, "printable") == 0) format = FORMAT_MODIFIER_PRINTABLE;
     else if (strcmp(formatString, "year") == 0) format = FORMAT_MODIFIER_YEAR;
@@ -301,6 +315,7 @@
     else if (strcmp(formatString, "epoch") == 0) format = FORMAT_MODIFIER_EPOCH;
     else if (strcmp(formatString, "monotonic") == 0) format = FORMAT_MODIFIER_MONOTONIC;
     else if (strcmp(formatString, "uid") == 0) format = FORMAT_MODIFIER_UID;
+    else if (strcmp(formatString, "descriptive") == 0) format = FORMAT_MODIFIER_DESCRIPT;
     else {
         extern char *tzname[2];
         static const char gmt[] = "GMT";
@@ -566,6 +581,19 @@
     return ((uint64_t) high << 32) | (uint64_t) low;
 }
 
+static bool findChar(const char** cp, size_t* len, int c) {
+    while (*len && isspace(**cp)) {
+        ++*cp;
+        --*len;
+    }
+    if (c == INT_MAX) return *len;
+    if (*len && (**cp == c)) {
+        ++*cp;
+        --*len;
+        return true;
+    }
+    return false;
+}
 
 /*
  * Recursively convert binary log data to printable form.
@@ -578,27 +606,128 @@
  *
  * Returns 0 on success, 1 on buffer full, -1 on failure.
  */
+enum objectType {
+    TYPE_OBJECTS      = '1',
+    TYPE_BYTES        = '2',
+    TYPE_MILLISECONDS = '3',
+    TYPE_ALLOCATIONS  = '4',
+    TYPE_ID           = '5',
+    TYPE_PERCENT      = '6'
+};
+
 static int android_log_printBinaryEvent(const unsigned char** pEventData,
-    size_t* pEventDataLen, char** pOutBuf, size_t* pOutBufLen)
+    size_t* pEventDataLen, char** pOutBuf, size_t* pOutBufLen,
+    const char** fmtStr, size_t* fmtLen)
 {
     const unsigned char* eventData = *pEventData;
     size_t eventDataLen = *pEventDataLen;
     char* outBuf = *pOutBuf;
+    char* outBufSave = outBuf;
     size_t outBufLen = *pOutBufLen;
+    size_t outBufLenSave = outBufLen;
     unsigned char type;
     size_t outCount;
     int result = 0;
+    const char* cp;
+    size_t len;
+    int64_t lval;
 
     if (eventDataLen < 1)
         return -1;
     type = *eventData++;
     eventDataLen--;
 
+    cp = NULL;
+    len = 0;
+    if (fmtStr && *fmtStr && fmtLen && *fmtLen && **fmtStr) {
+        cp = *fmtStr;
+        len = *fmtLen;
+    }
+    /*
+     * event.logtag format specification:
+     *
+     * Optionally, after the tag names can be put a description for the value(s)
+     * of the tag. Description are in the format
+     *    (<name>|data type[|data unit])
+     * Multiple values are separated by commas.
+     *
+     * The data type is a number from the following values:
+     * 1: int
+     * 2: long
+     * 3: string
+     * 4: list
+     * 5: float
+     *
+     * The data unit is a number taken from the following list:
+     * 1: Number of objects
+     * 2: Number of bytes
+     * 3: Number of milliseconds
+     * 4: Number of allocations
+     * 5: Id
+     * 6: Percent
+     * Default value for data of type int/long is 2 (bytes).
+     */
+    if (!cp || !findChar(&cp, &len, '(')) {
+        len = 0;
+    } else {
+        char* outBufLastSpace = NULL;
+
+        findChar(&cp, &len, INT_MAX);
+        while (len && *cp && (*cp != '|') && (*cp != ')')) {
+            if (outBufLen <= 0) {
+                /* halt output */
+                goto no_room;
+            }
+            outBufLastSpace = isspace(*cp) ? outBuf : NULL;
+            *outBuf = *cp;
+            ++outBuf;
+            ++cp;
+            --outBufLen;
+            --len;
+        }
+        if (outBufLastSpace) {
+            outBufLen += outBuf - outBufLastSpace;
+            outBuf = outBufLastSpace;
+        }
+        if (outBufLen <= 0) {
+            /* halt output */
+            goto no_room;
+        }
+        if (outBufSave != outBuf) {
+            *outBuf = '=';
+            ++outBuf;
+            --outBufLen;
+        }
+
+        if (findChar(&cp, &len, '|') && findChar(&cp, &len, INT_MAX)) {
+            static const unsigned char typeTable[] = {
+                EVENT_TYPE_INT,
+                EVENT_TYPE_LONG,
+                EVENT_TYPE_STRING,
+                EVENT_TYPE_LIST,
+                EVENT_TYPE_FLOAT
+            };
+
+            if ((*cp >= '1') &&
+                (*cp < (char)('1' + (sizeof(typeTable) / sizeof(typeTable[0])))) &&
+                (type != typeTable[(size_t)(*cp - '1')])) len = 0;
+
+            if (len) {
+                ++cp;
+                --len;
+            } else {
+                /* reset the format */
+                outBuf = outBufSave;
+                outBufLen = outBufLenSave;
+            }
+        }
+    }
+    lval = 0;
     switch (type) {
     case EVENT_TYPE_INT:
         /* 32-bit signed int */
         {
-            int ival;
+            int32_t ival;
 
             if (eventDataLen < 4)
                 return -1;
@@ -606,35 +735,24 @@
             eventData += 4;
             eventDataLen -= 4;
 
-            outCount = snprintf(outBuf, outBufLen, "%d", ival);
-            if (outCount < outBufLen) {
-                outBuf += outCount;
-                outBufLen -= outCount;
-            } else {
-                /* halt output */
-                goto no_room;
-            }
+            lval = ival;
         }
-        break;
+        goto pr_lval;
     case EVENT_TYPE_LONG:
         /* 64-bit signed long */
-        {
-            uint64_t lval;
-
-            if (eventDataLen < 8)
-                return -1;
-            lval = get8LE(eventData);
-            eventData += 8;
-            eventDataLen -= 8;
-
-            outCount = snprintf(outBuf, outBufLen, "%" PRId64, lval);
-            if (outCount < outBufLen) {
-                outBuf += outCount;
-                outBufLen -= outCount;
-            } else {
-                /* halt output */
-                goto no_room;
-            }
+        if (eventDataLen < 8)
+            return -1;
+        lval = get8LE(eventData);
+        eventData += 8;
+        eventDataLen -= 8;
+    pr_lval:
+        outCount = snprintf(outBuf, outBufLen, "%" PRId64, lval);
+        if (outCount < outBufLen) {
+            outBuf += outCount;
+            outBufLen -= outCount;
+        } else {
+            /* halt output */
+            goto no_room;
         }
         break;
     case EVENT_TYPE_FLOAT:
@@ -674,6 +792,11 @@
             if (eventDataLen < strLen)
                 return -1;
 
+            if (cp && (strLen == 0)) {
+                /* reset the format if no content */
+                outBuf = outBufSave;
+                outBufLen = outBufLenSave;
+            }
             if (strLen < outBufLen) {
                 memcpy(outBuf, eventData, strLen);
                 outBuf += strLen;
@@ -710,7 +833,7 @@
 
             for (i = 0; i < count; i++) {
                 result = android_log_printBinaryEvent(&eventData, &eventDataLen,
-                        &outBuf, &outBufLen);
+                        &outBuf, &outBufLen, fmtStr, fmtLen);
                 if (result != 0)
                     goto bail;
 
@@ -736,12 +859,90 @@
         fprintf(stderr, "Unknown binary event type %d\n", type);
         return -1;
     }
+    if (cp && len) {
+        if (findChar(&cp, &len, '|') && findChar(&cp, &len, INT_MAX)) {
+            switch (*cp) {
+            case TYPE_OBJECTS:
+                outCount = 0;
+                /* outCount = snprintf(outBuf, outBufLen, " objects"); */
+                break;
+            case TYPE_BYTES:
+                if ((lval != 0) && ((lval % 1024) == 0)) {
+                    /* repaint with multiplier */
+                    static const char suffixTable[] = { 'K', 'M', 'G', 'T' };
+                    size_t idx = 0;
+                    outBuf -= outCount;
+                    outBufLen += outCount;
+                    do {
+                        lval /= 1024;
+                        if ((lval % 1024) != 0) break;
+                    } while (++idx < ((sizeof(suffixTable) /
+                                       sizeof(suffixTable[0])) - 1));
+                    outCount = snprintf(outBuf, outBufLen,
+                                        "%" PRId64 "%cB",
+                                        lval, suffixTable[idx]);
+                } else {
+                    outCount = snprintf(outBuf, outBufLen, "B");
+                }
+                break;
+            case TYPE_MILLISECONDS:
+                if (((lval <= -1000) || (1000 <= lval)) &&
+                        (outBufLen || (outBuf[-1] == '0'))) {
+                    /* repaint as (fractional) seconds, possibly saving space */
+                    if (outBufLen) outBuf[0] = outBuf[-1];
+                    outBuf[-1] = outBuf[-2];
+                    outBuf[-2] = outBuf[-3];
+                    outBuf[-3] = '.';
+                    while ((outBufLen == 0) || (*outBuf == '0')) {
+                        --outBuf;
+                        ++outBufLen;
+                    }
+                    if (*outBuf != '.') {
+                       ++outBuf;
+                       --outBufLen;
+                    }
+                    outCount = snprintf(outBuf, outBufLen, "s");
+                } else {
+                    outCount = snprintf(outBuf, outBufLen, "ms");
+                }
+                break;
+            case TYPE_ALLOCATIONS:
+                outCount = 0;
+                /* outCount = snprintf(outBuf, outBufLen, " allocations"); */
+                break;
+            case TYPE_ID:
+                outCount = 0;
+                break;
+            case TYPE_PERCENT:
+                outCount = snprintf(outBuf, outBufLen, "%%");
+                break;
+            default: /* ? */
+                outCount = 0;
+                break;
+            }
+            ++cp;
+            --len;
+            if (outCount < outBufLen) {
+                outBuf += outCount;
+                outBufLen -= outCount;
+            } else if (outCount) {
+                /* halt output */
+                goto no_room;
+            }
+        }
+        if (!findChar(&cp, &len, ')')) len = 0;
+        if (!findChar(&cp, &len, ',')) len = 0;
+    }
 
 bail:
     *pEventData = eventData;
     *pEventDataLen = eventDataLen;
     *pOutBuf = outBuf;
     *pOutBufLen = outBufLen;
+    if (cp) {
+        *fmtStr = cp;
+        *fmtLen = len;
+    }
     return result;
 
 no_room:
@@ -764,7 +965,7 @@
         char *messageBuf, int messageBufLen)
 {
     size_t inCount;
-    unsigned int tagIndex;
+    uint32_t tagIndex;
     const unsigned char* eventData;
 
     entry->tv_sec = buf->sec;
@@ -817,7 +1018,7 @@
     if (entry->tag == NULL) {
         size_t tagLen;
 
-        tagLen = snprintf(messageBuf, messageBufLen, "[%d]", tagIndex);
+        tagLen = snprintf(messageBuf, messageBufLen, "[%" PRIu32 "]", tagIndex);
         if (tagLen >= (size_t)messageBufLen) {
             tagLen = messageBufLen - 1;
         }
@@ -831,10 +1032,27 @@
      * Format the event log data into the buffer.
      */
     char* outBuf = messageBuf;
-    size_t outRemaining = messageBufLen-1;      /* leave one for nul byte */
+    size_t outRemaining = messageBufLen - 1; /* leave one for nul byte */
     int result;
+    const char* fmtStr = NULL;
+    size_t fmtLen = 0;
+    if (descriptive_output && map) {
+        fmtStr = android_lookupEventFormat_len(map, &fmtLen, tagIndex);
+    }
     result = android_log_printBinaryEvent(&eventData, &inCount, &outBuf,
-                &outRemaining);
+                &outRemaining, &fmtStr, &fmtLen);
+    if ((result == 1) && fmtStr) {
+        /* We overflowed :-(, let's repaint the line w/o format dressings */
+        eventData = (const unsigned char*)buf->msg;
+        if (buf2->hdr_size) {
+            eventData = ((unsigned char *)buf2) + buf2->hdr_size;
+        }
+        eventData += 4;
+        outBuf = messageBuf;
+        outRemaining = messageBufLen - 1;
+        result = android_log_printBinaryEvent(&eventData, &inCount, &outBuf,
+                                              &outRemaining, NULL, NULL);
+    }
     if (result < 0) {
         fprintf(stderr, "Binary log entry conversion failed\n");
         return -1;
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index f08a6cd..d0c693d 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -82,8 +82,14 @@
 static size_t g_printCount;
 static bool g_printItAnyways;
 
+enum helpType {
+    HELP_FALSE,
+    HELP_TRUE,
+    HELP_FORMAT
+};
+
 // if showHelp is set, newline required in fmt statement to transition to usage
-__noreturn static void logcat_panic(bool showHelp, const char *fmt, ...) __printflike(2,3);
+__noreturn static void logcat_panic(enum helpType showHelp, const char *fmt, ...) __printflike(2,3);
 
 static int openLogFile (const char *pathname)
 {
@@ -133,7 +139,7 @@
     g_outFD = openLogFile(g_outputFileName);
 
     if (g_outFD < 0) {
-        logcat_panic(false, "couldn't open output file");
+        logcat_panic(HELP_FALSE, "couldn't open output file");
     }
 
     g_outByteCount = 0;
@@ -196,7 +202,7 @@
             bytesWritten = android_log_printLogLine(g_logformat, g_outFD, &entry);
 
             if (bytesWritten < 0) {
-                logcat_panic(false, "output error");
+                logcat_panic(HELP_FALSE, "output error");
             }
         }
     }
@@ -210,7 +216,6 @@
     }
 
 error:
-    //fprintf (stderr, "Error processing record\n");
     return;
 }
 
@@ -222,7 +227,7 @@
                      dev->printed ? "switch to" : "beginning of",
                      dev->device);
             if (write(g_outFD, buf, strlen(buf)) < 0) {
-                logcat_panic(false, "output error");
+                logcat_panic(HELP_FALSE, "output error");
             }
         }
         dev->printed = true;
@@ -256,18 +261,18 @@
     g_outFD = openLogFile (g_outputFileName);
 
     if (g_outFD < 0) {
-        logcat_panic(false, "couldn't open output file");
+        logcat_panic(HELP_FALSE, "couldn't open output file");
     }
 
     struct stat statbuf;
     if (fstat(g_outFD, &statbuf) == -1) {
         close(g_outFD);
-        logcat_panic(false, "couldn't get output file stat\n");
+        logcat_panic(HELP_FALSE, "couldn't get output file stat\n");
     }
 
     if ((size_t) statbuf.st_size > SIZE_MAX || statbuf.st_size < 0) {
         close(g_outFD);
-        logcat_panic(false, "invalid output file stat\n");
+        logcat_panic(HELP_FALSE, "invalid output file stat\n");
     }
 
     g_outByteCount = statbuf.st_size;
@@ -288,9 +293,10 @@
                     "                  the fileset and continue\n"
                     "  -v <format>, --format=<format>\n"
                     "                  Sets log print format verb and adverbs, where <format> is:\n"
-                    "                    brief long process raw tag thread threadtime time\n"
+                    "                    brief help long process raw tag thread threadtime time\n"
                     "                  and individually flagged modifying adverbs can be added:\n"
-                    "                    color epoch monotonic printable uid usec UTC year zone\n"
+                    "                    color descriptive epoch monotonic printable uid\n"
+                    "                    usec UTC year zone\n"
                     "  -D, --dividers  Print dividers between each log buffer\n"
                     "  -c, --clear     Clear (flush) the entire log and exit\n"
                     "                  if Log to File specified, clear fileset instead\n"
@@ -356,6 +362,40 @@
                    "or defaults to \"threadtime\"\n\n");
 }
 
+static void show_format_help()
+{
+    fprintf(stderr,
+        "-v <format>, --format=<format> options:\n"
+        "  Sets log print format verb and adverbs, where <format> is:\n"
+        "    brief long process raw tag thread threadtime time\n"
+        "  and individually flagged modifying adverbs can be added:\n"
+        "    color descriptive epoch monotonic printable uid usec UTC year zone\n"
+        "\nSingle format verbs:\n"
+        "  brief      — Display priority/tag and PID of the process issuing the message.\n"
+        "  long       — Display all metadata fields, separate messages with blank lines.\n"
+        "  process    — Display PID only.\n"
+        "  raw        — Display the raw log message, with no other metadata fields.\n"
+        "  tag        — Display the priority/tag only.\n"
+        "  threadtime — Display the date, invocation time, priority, tag, and the PID\n"
+        "               and TID of the thread issuing the message. (the default format).\n"
+        "  time       — Display the date, invocation time, priority/tag, and PID of the\n"
+        "             process issuing the message.\n"
+        "\nAdverb modifiers can be used in combination:\n"
+        "  color       — Display in highlighted color to match priority. i.e. \x1B[38;5;231mVERBOSE\n"
+        "                \x1B[38;5;75mDEBUG \x1B[38;5;40mINFO \x1B[38;5;166mWARNING \x1B[38;5;196mERROR FATAL\x1B[0m\n"
+        "  descriptive — events logs only, descriptions from event-log-tags database.\n"
+        "  epoch       — Display time as seconds since Jan 1 1970.\n"
+        "  monotonic   — Display time as cpu seconds since last boot.\n"
+        "  printable   — Ensure that any binary logging content is escaped.\n"
+        "  uid         — If permitted, display the UID or Android ID of logged process.\n"
+        "  usec        — Display time down the microsecond precision.\n"
+        "  UTC         — Display time as UTC.\n"
+        "  year        — Add the year to the displayed time.\n"
+        "  zone        — Add the local timezone to the displayed time.\n"
+        "  \"<zone>\"    — Print using this public named timezone (experimental).\n\n"
+    );
+}
+
 static int setLogFormat(const char * formatString)
 {
     static AndroidLogPrintFormat format;
@@ -418,15 +458,23 @@
     return true;
 }
 
-static void logcat_panic(bool showHelp, const char *fmt, ...)
+static void logcat_panic(enum helpType showHelp, const char *fmt, ...)
 {
     va_list  args;
     va_start(args, fmt);
     vfprintf(stderr, fmt,  args);
     va_end(args);
 
-    if (showHelp) {
+    switch (showHelp) {
+    case HELP_TRUE:
        show_help(getprogname());
+       break;
+    case HELP_FORMAT:
+       show_format_help();
+       break;
+    case HELP_FALSE:
+    default:
+      break;
     }
 
     exit(EXIT_FAILURE);
@@ -616,7 +664,7 @@
                 if (long_options[option_index].name == pid_str) {
                     // ToDo: determine runtime PID_MAX?
                     if (!getSizeTArg(optarg, &pid, 1)) {
-                        logcat_panic(true, "%s %s out of range\n",
+                        logcat_panic(HELP_TRUE, "%s %s out of range\n",
                                      long_options[option_index].name, optarg);
                     }
                     break;
@@ -628,7 +676,7 @@
                     // ToDo: implement API that supports setting a wrap timeout
                     size_t dummy = ANDROID_LOG_WRAP_DEFAULT_TIMEOUT;
                     if (optarg && !getSizeTArg(optarg, &dummy, 1)) {
-                        logcat_panic(true, "%s %s out of range\n",
+                        logcat_panic(HELP_TRUE, "%s %s out of range\n",
                                      long_options[option_index].name, optarg);
                     }
                     if (dummy != ANDROID_LOG_WRAP_DEFAULT_TIMEOUT) {
@@ -675,7 +723,8 @@
                 if (strspn(optarg, "0123456789") != strlen(optarg)) {
                     char *cp = parseTime(tail_time, optarg);
                     if (!cp) {
-                        logcat_panic(false, "-%c \"%s\" not in time format\n",
+                        logcat_panic(HELP_FALSE,
+                                     "-%c \"%s\" not in time format\n",
                                      ret, optarg);
                     }
                     if (*cp) {
@@ -707,7 +756,7 @@
             case 'm': {
                 char *end = NULL;
                 if (!getSizeTArg(optarg, &g_maxCount)) {
-                    logcat_panic(false, "-%c \"%s\" isn't an "
+                    logcat_panic(HELP_FALSE, "-%c \"%s\" isn't an "
                                  "integer greater than zero\n", ret, optarg);
                 }
             }
@@ -780,7 +829,8 @@
                         const char *name = android_log_id_to_name(log_id);
 
                         if (strcmp(name, optarg) != 0) {
-                            logcat_panic(true, "unknown buffer %s\n", optarg);
+                            logcat_panic(HELP_TRUE,
+                                         "unknown buffer %s\n", optarg);
                         }
                         idMask |= (1 << log_id);
                     }
@@ -841,20 +891,27 @@
 
             case 'r':
                 if (!getSizeTArg(optarg, &g_logRotateSizeKBytes, 1)) {
-                    logcat_panic(true, "Invalid parameter %s to -r\n", optarg);
+                    logcat_panic(HELP_TRUE,
+                                 "Invalid parameter \"%s\" to -r\n", optarg);
                 }
             break;
 
             case 'n':
                 if (!getSizeTArg(optarg, &g_maxRotatedLogs, 1)) {
-                    logcat_panic(true, "Invalid parameter %s to -n\n", optarg);
+                    logcat_panic(HELP_TRUE,
+                                 "Invalid parameter \"%s\" to -n\n", optarg);
                 }
             break;
 
             case 'v':
-                err = setLogFormat (optarg);
+                if (!strcmp(optarg, "help") || !strcmp(optarg, "--help")) {
+                    show_format_help();
+                    exit(0);
+                }
+                err = setLogFormat(optarg);
                 if (err < 0) {
-                    logcat_panic(true, "Invalid parameter %s to -v\n", optarg);
+                    logcat_panic(HELP_FORMAT,
+                                 "Invalid parameter \"%s\" to -v\n", optarg);
                 }
                 hasSetLogFormat |= err;
             break;
@@ -932,17 +989,20 @@
                 break;
 
             case ':':
-                logcat_panic(true, "Option -%c needs an argument\n", optopt);
+                logcat_panic(HELP_TRUE,
+                             "Option -%c needs an argument\n", optopt);
                 break;
 
             default:
-                logcat_panic(true, "Unrecognized Option %c\n", optopt);
+                logcat_panic(HELP_TRUE,
+                             "Unrecognized Option %c\n", optopt);
                 break;
         }
     }
 
     if (g_maxCount && got_t) {
-        logcat_panic(true, "Cannot use -m (--max-count) and -t together\n");
+        logcat_panic(HELP_TRUE,
+                     "Cannot use -m (--max-count) and -t together\n");
     }
     if (g_printItAnyways && (!g_regex || !g_maxCount)) {
         // One day it would be nice if --print -v color and --regex <expr>
@@ -968,12 +1028,12 @@
     }
 
     if (g_logRotateSizeKBytes != 0 && g_outputFileName == NULL) {
-        logcat_panic(true, "-r requires -f as well\n");
+        logcat_panic(HELP_TRUE, "-r requires -f as well\n");
     }
 
     if (setId != NULL) {
         if (g_outputFileName == NULL) {
-            logcat_panic(true, "--id='%s' requires -f as well\n", setId);
+            logcat_panic(HELP_TRUE, "--id='%s' requires -f as well\n", setId);
         }
 
         std::string file_name = android::base::StringPrintf("%s.id", g_outputFileName);
@@ -1003,7 +1063,8 @@
     if (forceFilters) {
         err = android_log_addFilterString(g_logformat, forceFilters);
         if (err < 0) {
-            logcat_panic(false, "Invalid filter expression in logcat args\n");
+            logcat_panic(HELP_FALSE,
+                         "Invalid filter expression in logcat args\n");
         }
     } else if (argc == optind) {
         // Add from environment variable
@@ -1013,7 +1074,7 @@
             err = android_log_addFilterString(g_logformat, env_tags_orig);
 
             if (err < 0) {
-                logcat_panic(true,
+                logcat_panic(HELP_TRUE,
                             "Invalid filter expression in ANDROID_LOG_TAGS\n");
             }
         }
@@ -1023,7 +1084,8 @@
             err = android_log_addFilterString(g_logformat, argv[i]);
 
             if (err < 0) {
-                logcat_panic(true, "Invalid filter expression '%s'\n", argv[i]);
+                logcat_panic(HELP_TRUE,
+                             "Invalid filter expression '%s'\n", argv[i]);
             }
         }
     }
@@ -1109,17 +1171,20 @@
     }
     // report any errors in the above loop and exit
     if (openDeviceFail) {
-        logcat_panic(false, "Unable to open log device '%s'\n", openDeviceFail);
+        logcat_panic(HELP_FALSE,
+                     "Unable to open log device '%s'\n", openDeviceFail);
     }
     if (clearFail) {
-        logcat_panic(false, "failed to clear the '%s' log\n", clearFail);
+        logcat_panic(HELP_FALSE,
+                     "failed to clear the '%s' log\n", clearFail);
     }
     if (setSizeFail) {
-        logcat_panic(false, "failed to set the '%s' log size\n", setSizeFail);
+        logcat_panic(HELP_FALSE,
+                     "failed to set the '%s' log size\n", setSizeFail);
     }
     if (getSizeFail) {
-        logcat_panic(false, "failed to get the readable '%s' log size",
-                     getSizeFail);
+        logcat_panic(HELP_FALSE,
+                     "failed to get the readable '%s' log size", getSizeFail);
     }
 
     if (setPruneList) {
@@ -1130,11 +1195,11 @@
         if (asprintf(&buf, "%-*s", (int)(bLen - 1), setPruneList) > 0) {
             buf[len] = '\0';
             if (android_logger_set_prune_list(logger_list, buf, bLen)) {
-                logcat_panic(false, "failed to set the prune list");
+                logcat_panic(HELP_FALSE, "failed to set the prune list");
             }
             free(buf);
         } else {
-            logcat_panic(false, "failed to set the prune list (alloc)");
+            logcat_panic(HELP_FALSE, "failed to set the prune list (alloc)");
         }
     }
 
@@ -1165,7 +1230,7 @@
         }
 
         if (!buf) {
-            logcat_panic(false, "failed to read data");
+            logcat_panic(HELP_FALSE, "failed to read data");
         }
 
         // remove trailing FF
@@ -1217,7 +1282,7 @@
         int ret = android_logger_list_read(logger_list, &log_msg);
 
         if (ret == 0) {
-            logcat_panic(false, "read: unexpected EOF!\n");
+            logcat_panic(HELP_FALSE, "read: unexpected EOF!\n");
         }
 
         if (ret < 0) {
@@ -1226,12 +1291,12 @@
             }
 
             if (ret == -EIO) {
-                logcat_panic(false, "read: unexpected EOF!\n");
+                logcat_panic(HELP_FALSE, "read: unexpected EOF!\n");
             }
             if (ret == -EINVAL) {
-                logcat_panic(false, "read: unexpected length.\n");
+                logcat_panic(HELP_FALSE, "read: unexpected length.\n");
             }
-            logcat_panic(false, "logcat read failure");
+            logcat_panic(HELP_FALSE, "logcat read failure");
         }
 
         for (d = devices; d; d = d->next) {
diff --git a/logcat/tests/logcat_test.cpp b/logcat/tests/logcat_test.cpp
index bc0ea52..18067dc 100644
--- a/logcat/tests/logcat_test.cpp
+++ b/logcat/tests/logcat_test.cpp
@@ -25,6 +25,7 @@
 #include <sys/wait.h>
 
 #include <memory>
+#include <string>
 
 #include <gtest/gtest.h>
 #include <log/log.h>
@@ -1235,3 +1236,163 @@
 
     ASSERT_EQ(3, count);
 }
+
+static bool End_to_End(const char* tag, const char* fmt, ...)
+#if defined(__GNUC__)
+    __attribute__((__format__(printf, 2, 3)))
+#endif
+    ;
+
+static bool End_to_End(const char* tag, const char* fmt, ...) {
+    FILE *fp = popen("logcat -v brief -b events -v descriptive -t 100 2>/dev/null", "r");
+    if (!fp) return false;
+
+    char buffer[BIG_BUFFER];
+    va_list ap;
+
+    va_start(ap, fmt);
+    vsnprintf(buffer, sizeof(buffer), fmt, ap);
+    va_end(ap);
+
+    char *str = NULL;
+    asprintf(&str, "I/%s ( %%d): %s%%c", tag, buffer);
+    std::string expect(str);
+    free(str);
+
+    int count = 0;
+    pid_t pid = getpid();
+    std::string lastMatch;
+    while (fgets(buffer, sizeof(buffer), fp)) {
+        char newline;
+        int p;
+        int ret = sscanf(buffer, expect.c_str(), &p, &newline);
+        if ((2 == ret) && (p == pid) && (newline == '\n')) ++count;
+        else if ((1 == ret) && (p == pid) && (count == 0)) lastMatch = buffer;
+    }
+
+    pclose(fp);
+
+    if ((count == 0) && (lastMatch.length() > 0)) {
+        // Help us pinpoint where things went wrong ...
+        fprintf(stderr, "Closest match for\n    %s\n  is\n    %s",
+                expect.c_str(), lastMatch.c_str());
+    }
+
+    return count == 1;
+}
+
+TEST(logcat, descriptive) {
+    struct tag {
+        uint32_t tagNo;
+        const char* tagStr;
+    };
+
+    {
+        static const struct tag hhgtg = { 42, "answer" };
+        android_log_event_context ctx(hhgtg.tagNo);
+        static const char theAnswer[] = "what is five by seven";
+        ctx << theAnswer;
+        ctx.write();
+        EXPECT_TRUE(End_to_End(hhgtg.tagStr,
+                               "to life the universe etc=%s", theAnswer));
+    }
+
+    {
+        static const struct tag sync = { 2720, "sync" };
+        static const char id[] = "logcat.decriptive";
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << id << (int32_t)42 << (int32_t)-1 << (int32_t)0;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr,
+                                   "[id=%s,event=42,source=-1,account=0]",
+                                   id));
+        }
+
+        // Partial match to description
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << id << (int32_t)43 << (int64_t)-1 << (int32_t)0;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr,
+                                   "[id=%s,event=43,-1,0]",
+                                   id));
+        }
+
+        // Negative Test of End_to_End, ensure it is working
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << id << (int32_t)44 << (int32_t)-1 << (int64_t)0;
+            ctx.write();
+            fprintf(stderr, "Expect a \"Closest match\" message\n");
+            EXPECT_FALSE(End_to_End(sync.tagStr,
+                                    "[id=%s,event=44,source=-1,account=0]",
+                                    id));
+        }
+    }
+
+    {
+        static const struct tag sync = { 2747, "contacts_aggregation" };
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint64_t)30 << (int32_t)2;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr,
+                                   "[aggregation time=30ms,count=2]"));
+        }
+
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint64_t)31570 << (int32_t)911;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr,
+                                   "[aggregation time=31.57s,count=911]"));
+        }
+    }
+
+    {
+        static const struct tag sync = { 75000, "sqlite_mem_alarm_current" };
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint32_t)512;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr, "current=512B"));
+        }
+
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint32_t)3072;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr, "current=3KB"));
+        }
+
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint32_t)2097152;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr, "current=2MB"));
+        }
+
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint32_t)2097153;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr, "current=2097153B"));
+        }
+
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint32_t)1073741824;
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr, "current=1GB"));
+        }
+
+        {
+            android_log_event_context ctx(sync.tagNo);
+            ctx << (uint32_t)3221225472; // 3MB, but on purpose overflowed
+            ctx.write();
+            EXPECT_TRUE(End_to_End(sync.tagStr, "current=-1GB"));
+        }
+    }
+
+}