mood: Make "duration" a new keyword for the mood grammar.

The new keyword makes it possible to define moods which impose a
constraint on the duration of the admissible files. For example,
the expression

	duration < 120 * 1000

selects only files which are shorter than two minutes.

The implementation is pretty simple.

diff --git a/mp.c b/mp.c
index 416b4f92065ef79716e7f966c3102e995071a112..b5fa9cacaa6dcf9f3e2ef6f99fd025757f12097c 100644 (file)
--- a/mp.c
+++ b/mp.c
@@ -389,6 +389,27 @@ MP_AFHI(frequency)
 MP_AFHI(channels)
 /** \endcond */
 
+/**
+ * Return the duration of the audio file from the afh info structure.
+ *
+ * \param ctx See \ref mp_path().
+ *
+ * The duration is computed by multiplying the number of chunks and the
+ * duration of one chunk.
+ *
+ * \return The approximate number of milliseconds.
+ */
+int64_t mp_duration(struct mp_context *ctx)
+{
+       struct timeval tmp;
+       int ret = get_afhi(ctx);
+
+       if (ret < 0)
+               return 0;
+       tv_scale(ctx->afhi.chunks_total, &ctx->afhi.chunk_tv, &tmp);
+       return tv2ms(&tmp);
+}
+
 /**
  * Define a function which extracts and returns the value of a meta tag.
  *

diff --git a/mp.h b/mp.h
index febbe3240f49ba81b08ca2168b10dd1189fc3f54..891bfb054e2f4cf1a922e7434a8467808f2e474b 100644 (file)
--- a/mp.h
+++ b/mp.h
@@ -139,6 +139,7 @@ bool mp_is_set(const char *attr, struct mp_context *ctx);
 char *mp_path(struct mp_context *ctx);
 int64_t mp_year(struct mp_context *ctx);
 int64_t mp_num_attributes_set(struct mp_context *ctx);
+int64_t mp_duration(struct mp_context *ctx);
 
 /* Generated with MP_AFSI() */
 /** \cond MP_AFSI */

diff --git a/web/manual.md b/web/manual.md
index db28a699bdd05516d17de4bf837cc110f737df7e..d73263b3929ba75cef49073011005f2996ab2270 100644 (file)
--- a/web/manual.md
+++ b/web/manual.md
@@ -1023,6 +1023,7 @@ Keyword              |    Type | Semantic value
 `bitrate`            | integer | The average bitrate
 `frequency`          | integer | The output sample rate
 `channels`           | integer | The number of channels
+`duration`           | integer | The number of milliseconds
 `is_set("foo")`      | boolean | True if attribute "foo" is set.
 
 [\*] For most audio formats, the year tag is stored as a string. It

diff --git a/yy/mp.lex b/yy/mp.lex
index 2dbe21b779a82eebd79403fa5f60bc56925489dd..4a53db2741754bf6359733af8b42ca60ca255e92 100644 (file)
--- a/yy/mp.lex
+++ b/yy/mp.lex
@@ -74,6 +74,7 @@ lyrics_id {return LYRICS_ID;}
 bitrate {return BITRATE;}
 frequency {return FREQUENCY;}
 channels {return CHANNELS;}
+duration {return DURATION;}
 true {return TRUE;}
 false {return FALSE;}
 

diff --git a/yy/mp.y b/yy/mp.y
index 0f2c9cb8b256a82eeb2fac78114f6026902a24f2..06d76101daf42550ea192d1c963c32d5da6635d2 100644 (file)
--- a/yy/mp.y
+++ b/yy/mp.y
@@ -210,6 +210,9 @@ static int eval_node(struct mp_ast_node *node, struct mp_context *ctx,
        case CHANNELS:
                result->intval= mp_channels(ctx);
                return ST_INTVAL;
+       case DURATION:
+               result->intval= mp_duration(ctx);
+               return ST_INTVAL;
        /* bools */
        case IS_SET:
                arg = node->children[0]->sv.strval;
@@ -327,6 +330,7 @@ bool mp_eval_ast(struct mp_ast_node *root, struct mp_context *ctx)
 %token <node> BITRATE
 %token <node> FREQUENCY
 %token <node> CHANNELS
+%token <node> DURATION
 %token <node> FALSE TRUE
 
 /* keywords without semantic value */
@@ -377,6 +381,7 @@ exp: NUM {$$ = $1;}
        | BITRATE {$$ = mp_new_ast_leaf_node(BITRATE);}
        | FREQUENCY {$$ = mp_new_ast_leaf_node(FREQUENCY);}
        | CHANNELS {$$ = mp_new_ast_leaf_node(CHANNELS);}
+       | DURATION {$$ = mp_new_ast_leaf_node(DURATION);}
 ;
 
 boolexp: IS_SET '(' STRING_LITERAL ')' {$$ = ast_node_new_unary(IS_SET, $3);}