diff --git a/doc/filters.texi b/doc/filters.texi
index 8174b5b..1722d65 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -12546,10 +12546,10 @@ saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
 @anchor{signature}
 @section signature
 
-Calculates the MPEG-7 Video Signature. The filter could handle more than one
-input. In this case the matching between the inputs could be calculated. The
-filter passthrough the first input. The signature of each stream could be written
-into a file.
+Calculates the MPEG-7 Video Signature. The filter can handle more than one
+input. In this case the matching between the inputs can be calculated additionally.
+The filter always passes through the first input. The signature of each stream can
+be written into a file.
 
 It accepts the following options:
 
@@ -12563,10 +12563,10 @@ Available values are:
 @item off
 Disable the calculation of a matching (default).
 @item full
-Calculate the mathing for the whole video and output whether the whole video
+Calculate the matching for the whole video and output whether the whole video
 matches or only parts.
 @item fast
-Calculate as long as a matching is found or the video ends. Should be faster in
+Calculate only until a matching is found or the video ends. Should be faster in
 some cases.
 @end table
 
@@ -12624,7 +12624,7 @@ ffmpeg -i input.mkv -vf signature=filename=signature.bin -map 0:v -f null -
 @end example
 
 @item
-To detect whether two videos matches and store the signatures in XML format in
+To detect whether two videos match and store the signatures in XML format in
 signature0.xml and signature1.xml:
 @example
 ffmpeg -i input1.mkv -i input2.mkv -filter_complex "[0:v][1:v] signature=nb_inputs=2:detectmode=full:format=xml:filename=signature%d.xml" -map :v -f null -
diff --git a/libavfilter/signature.h b/libavfilter/signature.h
index 8c8f0a8..4728606 100644
--- a/libavfilter/signature.h
+++ b/libavfilter/signature.h
@@ -69,7 +69,7 @@ typedef struct {
     const Block* blocks;
 } ElemCat;
 
-typedef struct FineSignature{
+typedef struct FineSignature {
     struct FineSignature* next;
     struct FineSignature* prev;
     uint64_t pts;
@@ -79,15 +79,15 @@ typedef struct FineSignature{
     uint8_t framesig[SIGELEM_SIZE/5];
 } FineSignature;
 
-typedef struct CourseSignature{
+typedef struct CoarseSignature {
     uint8_t data[5][31]; /* 5 words with min. 243 bit */
     struct FineSignature* first; /* associated Finesignatures */
     struct FineSignature* last;
-    struct CourseSignature* next;
-} CourseSignature;
+    struct CoarseSignature* next;
+} CoarseSignature;
 
 /* lookup types */
-typedef struct MatchingInfo{
+typedef struct MatchingInfo {
     double meandist;
     double framerateratio; /* second/first */
     int score;
@@ -111,11 +111,11 @@ typedef struct {
     FineSignature* finesiglist;
     FineSignature* curfinesig;
 
-    CourseSignature* coursesiglist;
-    CourseSignature* courseend; /* needed for xml export */
+    CoarseSignature* coursesiglist;
+    CoarseSignature* courseend; /* needed for xml export */
     /* helpers to store the alternating signatures */
-    CourseSignature* curcoursesig1;
-    CourseSignature* curcoursesig2;
+    CoarseSignature* curcoursesig1;
+    CoarseSignature* curcoursesig2;
 
     int coursecount; /* counter from 0 to 89 */
     int midcourse;   /* whether it is a coursesignature beginning from 45 + i * 90 */
diff --git a/libavfilter/signature_lookup.c b/libavfilter/signature_lookup.c
index 3a75770..23c0ff1 100644
--- a/libavfilter/signature_lookup.c
+++ b/libavfilter/signature_lookup.c
@@ -39,7 +39,7 @@
 
 static void fill_l1distlut(uint8_t lut[])
 {
-    int i,j,tmp_i,tmp_j,count;
+    int i, j, tmp_i, tmp_j,count;
     uint8_t dist;
 
     for (i = 0, count = 0; i < 242; i++) {
@@ -91,7 +91,7 @@ static unsigned int get_l1dist(AVFilterContext *ctx, SignatureContext *sc, const
 {
     unsigned int i;
     unsigned int dist = 0;
-    uint8_t f,s;
+    uint8_t f, s;
 
     for (i = 0; i < SIGELEM_SIZE/5; i++) {
         if (first[i] != second[i]) {
@@ -112,7 +112,7 @@ static unsigned int get_l1dist(AVFilterContext *ctx, SignatureContext *sc, const
  * calculates the jaccard distance and evaluates a pair of course signatures as good
  * @return 0 if pair is bad, 1 otherwise
  */
-static int get_jaccarddist(SignatureContext *sc, CourseSignature *first, CourseSignature *second)
+static int get_jaccarddist(SignatureContext *sc, CoarseSignature *first, CoarseSignature *second)
 {
     int jaccarddist, i, composdist = 0, cwthcount = 0;
     for (i = 0; i < 5; i++) {
@@ -137,7 +137,7 @@ static int get_jaccarddist(SignatureContext *sc, CourseSignature *first, CourseS
  * step through the coursesignatures as long as a good candidate is found
  * @return 0 if no candidate is found, 1 otherwise
  */
-static int find_next_coursecandidate(SignatureContext *sc, CourseSignature *secondstart, CourseSignature **first, CourseSignature **second, int start)
+static int find_next_coursecandidate(SignatureContext *sc, CoarseSignature *secondstart, CoarseSignature **first, CoarseSignature **second, int start)
 {
     /* go one coursesignature foreword */
     if (!start) {
@@ -173,7 +173,7 @@ static int find_next_coursecandidate(SignatureContext *sc, CourseSignature *seco
  */
 static MatchingInfo* get_matching_parameters(AVFilterContext *ctx, SignatureContext *sc, FineSignature *first, FineSignature *second)
 {
-    FineSignature *f,*s;
+    FineSignature *f, *s;
     size_t i, j, k, l, hmax = 0, score;
     int framerate, offset, l1dist;
     double m;
@@ -421,7 +421,7 @@ static MatchingInfo evaluate_parameters(AVFilterContext *ctx, SignatureContext *
     int fcount = 0, goodfcount = 0, gooda = 0, goodb = 0;
     double meandist, minmeandist = bestmatch.meandist;
     int tolerancecount = 0;
-    FineSignature *a,*b, *aprev, *bprev;
+    FineSignature *a, *b, *aprev, *bprev;
     int status = STATUS_NULL;
 
     for (; infos != NULL; infos = infos->next) {
@@ -532,7 +532,7 @@ static void sll_free(MatchingInfo *sll)
 
 static MatchingInfo lookup_signatures(AVFilterContext *ctx, SignatureContext *sc, StreamContext *first, StreamContext *second, int mode)
 {
-    CourseSignature *cs, *cs2;
+    CoarseSignature *cs, *cs2;
     MatchingInfo *infos;
     MatchingInfo bestmatch;
     MatchingInfo *i;
diff --git a/libavfilter/vf_signature.c b/libavfilter/vf_signature.c
index ee01914..6db515c 100644
--- a/libavfilter/vf_signature.c
+++ b/libavfilter/vf_signature.c
@@ -41,28 +41,28 @@
 #define BLOCK_LCM (int64_t) 476985600
 
 static const AVOption signature_options[] = {
-    { "detectmode", "set the detectmode, possible values: off (default), full, fast",
+    { "detectmode", "set the detectmode",
         OFFSET(mode),         AV_OPT_TYPE_INT,    {.i64 = MODE_OFF}, 0, NB_LOOKUP_MODE-1, FLAGS, "mode" },
         { "off",  NULL, 0, AV_OPT_TYPE_CONST, {.i64 = MODE_OFF},  0, 0, .flags = FLAGS, "mode" },
         { "full", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = MODE_FULL}, 0, 0, .flags = FLAGS, "mode" },
         { "fast", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = MODE_FAST}, 0, 0, .flags = FLAGS, "mode" },
-    { "nb_inputs",  "set number of inputs",
+    { "nb_inputs",  "number of inputs",
         OFFSET(nb_inputs),    AV_OPT_TYPE_INT,    {.i64 = 1},        1, INT_MAX,          FLAGS },
-    { "filename",   "set filename for output files",
+    { "filename",   "filename for output files",
         OFFSET(filename),     AV_OPT_TYPE_STRING, {.str = ""},       0, NB_FORMATS-1,     FLAGS },
-    { "format",     "set output format, possible values: binary (default), xml",
+    { "format",     "set output format",
         OFFSET(format),       AV_OPT_TYPE_INT,    {.i64 = FORMAT_BINARY}, 0, 1,           FLAGS , "format" },
         { "binary", 0, 0, AV_OPT_TYPE_CONST, {.i64=FORMAT_BINARY}, 0, 0, FLAGS, "format" },
         { "xml",    0, 0, AV_OPT_TYPE_CONST, {.i64=FORMAT_XML},    0, 0, FLAGS, "format" },
-    { "th_d",       "set threshold to detect one word as similar",
+    { "th_d",       "threshold to detect one word as similar",
         OFFSET(thworddist),   AV_OPT_TYPE_INT,    {.i64 = 9000},     1, INT_MAX,          FLAGS },
-    { "th_dc",      "set threshold to detect all words as similar",
+    { "th_dc",      "threshold to detect all words as similar",
         OFFSET(thcomposdist), AV_OPT_TYPE_INT,    {.i64 = 60000},    1, INT_MAX,          FLAGS },
-    { "th_xh",      "set threshold to detect frames as similar",
+    { "th_xh",      "threshold to detect frames as similar",
         OFFSET(thl1),         AV_OPT_TYPE_INT,    {.i64 = 116},      1, INT_MAX,          FLAGS },
     { "th_di",      "minimum length of matching sequence in frames",
         OFFSET(thdi),         AV_OPT_TYPE_INT,    {.i64 = 0},        0, INT_MAX,          FLAGS },
-    { "th_it",      "set threshold for relation of good to all frames",
+    { "th_it",      "threshold for relation of good to all frames",
         OFFSET(thit),         AV_OPT_TYPE_DOUBLE, {.dbl = 0.5},    0.0, 1.0,              FLAGS },
     { NULL }
 };
@@ -113,7 +113,7 @@ static uint64_t get_block_sum(StreamContext *sc, uint64_t intpic[32][32], const
 {
     uint64_t sum = 0;
 
-    int x0,y0,x1,y1;
+    int x0, y0, x1, y1;
 
     x0 = b->up.x;
     y0 = b->up.y;
@@ -122,11 +122,11 @@ static uint64_t get_block_sum(StreamContext *sc, uint64_t intpic[32][32], const
 
     if (x0-1 >= 0 && y0-1 >= 0) {
         sum = intpic[y1][x1] + intpic[y0-1][x0-1] - intpic[y1][x0-1] - intpic[y0-1][x1];
-    }else if(x0-1 >= 0){
+    } else if (x0-1 >= 0) {
         sum = intpic[y1][x1] - intpic[y1][x0-1];
-    }else if(y0-1 >= 0){
+    } else if (y0-1 >= 0) {
         sum = intpic[y1][x1] - intpic[y0-1][x1];
-    }else{
+    } else {
         sum = intpic[y1][x1];
     }
     return sum;
@@ -171,7 +171,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
     int f = 0, g = 0, w = 0;
     int32_t dh1 = 1, dh2 = 1, dw1 = 1, dw2 = 1, a, b;
     int64_t denom;
-    int i,j,k,ternary;
+    int i, j, k, ternary;
     uint64_t blocksum;
     int blocksize;
     int64_t th; /* threshold */
@@ -321,7 +321,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
     /* coursesignature */
     if (sc->coursecount == 0) {
         if (sc->curcoursesig2) {
-            sc->curcoursesig1 = av_mallocz(sizeof(CourseSignature));
+            sc->curcoursesig1 = av_mallocz(sizeof(CoarseSignature));
             if (!sc->curcoursesig1)
                 return AVERROR(ENOMEM);
             sc->curcoursesig1->first = fs;
@@ -331,7 +331,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
     }
     if (sc->coursecount == 45) {
         sc->midcourse = 1;
-        sc->curcoursesig2 = av_mallocz(sizeof(CourseSignature));
+        sc->curcoursesig2 = av_mallocz(sizeof(CoarseSignature));
         if (!sc->curcoursesig2)
             return AVERROR(ENOMEM);
         sc->curcoursesig2->first = fs;
@@ -383,8 +383,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
 static int xml_export(AVFilterContext *ctx, StreamContext *sc, const char* filename)
 {
     FineSignature* fs;
-    CourseSignature* cs;
-    int i,j;
+    CoarseSignature* cs;
+    int i, j;
     FILE* f;
     unsigned int pot3[5] = { 3*3*3*3, 3*3*3, 3*3, 3, 1 };
 
@@ -490,9 +490,9 @@ static int binary_export(AVFilterContext *ctx, StreamContext *sc, const char* fi
 {
     FILE* f;
     FineSignature* fs;
-    CourseSignature* cs;
+    CoarseSignature* cs;
     uint32_t numofsegments = (sc->lastindex + 44)/45;
-    int i,j;
+    int i, j;
     PutBitContext buf;
     /* buffer + header + coursesignatures + finesignature */
     int len = (512 + 6 * 32 + 3*16 + 2 +
@@ -598,12 +598,12 @@ static int request_frame(AVFilterLink *outlink)
 
         ret = ff_request_frame(ctx->inputs[i]);
 
-        /* return if unexspected error occurs in input stream */
+        /* return if unexpected error occurs in input stream */
         if (ret < 0 && ret != AVERROR_EOF)
             return ret;
 
         /* export signature at EOF */
-        if (ret == AVERROR_EOF){
+        if (ret == AVERROR_EOF) {
             /* export if wanted */
             if (strlen(sic->filename) > 0) {
                 if (export(ctx, sc, i) < 0)
@@ -670,7 +670,7 @@ static av_cold int init(AVFilterContext *ctx)
             return AVERROR(ENOMEM);
         sc->curfinesig = NULL;
 
-        sc->coursesiglist = av_mallocz(sizeof(CourseSignature));
+        sc->coursesiglist = av_mallocz(sizeof(CoarseSignature));
         if (!sc->coursesiglist)
             return AVERROR(ENOMEM);
         sc->curcoursesig1 = sc->coursesiglist;
@@ -701,7 +701,7 @@ static av_cold void uninit(AVFilterContext *ctx)
     StreamContext *sc;
     void* tmp;
     FineSignature* finsig;
-    CourseSignature* cousig;
+    CoarseSignature* cousig;
     int i;
 
 
