mp4: Introduce mp4ff_get_duration().

This allows us to get rid of an ugly hack in aac_afh.c where we peeked
at the audio-specific config structure to get the scaling factor which
was needed to compute the duration.

diff --git a/aac_afh.c b/aac_afh.c
index dd9247d7ac6bba54a1c49512613ea8011a387a46..15e338e5b61efb84d39e24fbff17952137008871 100644 (file)
--- a/aac_afh.c
+++ b/aac_afh.c
@@ -24,7 +24,6 @@ struct aac_afh_context {
        size_t fpos;
        int32_t track;
        struct mp4ff *mp4ff;
-       mp4AudioSpecificConfig masc;
        struct mp4ff_callback cb;
 };
 
@@ -50,7 +49,7 @@ static uint32_t aac_afh_seek_cb(void *user_data, uint64_t pos)
        return 0;
 }
 
-static int32_t aac_afh_get_track(struct mp4ff *mp4ff, mp4AudioSpecificConfig *masc)
+static int32_t aac_afh_get_track(struct mp4ff *mp4ff)
 {
        int32_t i, rc, num_tracks = mp4ff_total_tracks(mp4ff);
 
@@ -61,7 +60,8 @@ static int32_t aac_afh_get_track(struct mp4ff *mp4ff, mp4AudioSpecificConfig *ma
 
                mp4ff_get_decoder_config(mp4ff, i, &buf, &buf_size);
                if (buf) {
-                       rc = NeAACDecAudioSpecificConfig(buf, buf_size, masc);
+                       mp4AudioSpecificConfig masc;
+                       rc = NeAACDecAudioSpecificConfig(buf, buf_size, &masc);
                        free(buf);
                        if (rc < 0)
                                continue;
@@ -87,7 +87,7 @@ static int aac_afh_open(const void *map, size_t mapsize, void **afh_context)
        c->mp4ff = mp4ff_open_read(&c->cb);
        if (!c->mp4ff)
                goto free_ctx;
-       c->track = aac_afh_get_track(c->mp4ff, &c->masc);
+       c->track = aac_afh_get_track(c->mp4ff);
        ret = -E_MP4FF_TRACK;
        if (c->track < 0)
                goto close_mp4ff;
@@ -145,7 +145,7 @@ static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
        int ret;
        int32_t rv;
        struct aac_afh_context *c;
-       int64_t tmp;
+       uint64_t milliseconds;
        const char *buf;
        uint32_t n, len;
 
@@ -176,11 +176,9 @@ static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
                        break;
                afhi->max_chunk_size = PARA_MAX(afhi->max_chunk_size, len);
        }
-
-       tmp = c->masc.sbr_present_flag == 1? 2048 : 1024;
-       afhi->seconds_total = tmp * afhi->chunks_total / afhi->frequency;
-       ms2tv(1000 * tmp / afhi->frequency, &afhi->chunk_tv);
-
+       milliseconds = mp4ff_get_duration(c->mp4ff, c->track);
+       afhi->seconds_total = milliseconds / 1000;
+       ms2tv(milliseconds / afhi->chunks_total, &afhi->chunk_tv);
        if (aac_afh_get_chunk(0, c, &buf, &len) >= 0)
                numbytes -= buf - map;
        afhi->bitrate = 8 * numbytes / afhi->seconds_total / 1000;

diff --git a/mp4.c b/mp4.c
index 548f78ec391e95f892fdba61cf2140db25a473d0..46aec2db6cf42ab50ecb2d99aef2bd0c7b4181f8 100644 (file)
--- a/mp4.c
+++ b/mp4.c
@@ -765,7 +765,6 @@ static int32_t tag_add_field(struct mp4ff_metadata *tags, const char *item,
 {
        if (!item || (item && !*item) || !value)
                return 0;
-
        tags->tags = para_realloc(tags->tags,
                (tags->count + 1) * sizeof(struct mp4ff_tag));
        tags->tags[tags->count].item = para_strdup(item);
@@ -1408,6 +1407,24 @@ static int32_t sample_to_offset(const struct mp4ff *f, int32_t track,
        return chunk_offset2;
 }
 
+/**
+ * Return the number of milliseconds of the given track.
+ *
+ * \param f As returned by \ref mp4ff_open_read(), must not be NULL.
+ * \param track Between zero and the value returned by \ref mp4ff_total_tracks().
+ *
+ * The function returns zero if the audio file is of zero length or contains a
+ * corrupt track header.
+ */
+uint64_t mp4ff_get_duration(const struct mp4ff *f, int32_t track)
+{
+       const struct mp4ff_track *t = f->track[track];
+
+       if (t->timeScale == 0)
+               return 0;
+       return t->duration * 1000 / t->timeScale;
+}
+
 void mp4ff_set_sample_position(struct mp4ff *f, int32_t track, int32_t sample)
 {
        int32_t offset = sample_to_offset(f, track, sample);

diff --git a/mp4.h b/mp4.h
index 8cd08ccfe1c03f80a439aa70399861b2b5c21821..ecab89b3080bcd42a7153233ed9c69b4a983ebc1 100644 (file)
--- a/mp4.h
+++ b/mp4.h
@@ -30,6 +30,7 @@ int32_t mp4ff_get_sample_size(const struct mp4ff *f, int track, int sample);
 uint32_t mp4ff_get_sample_rate(const struct mp4ff *f, int32_t track);
 uint32_t mp4ff_get_channel_count(const struct mp4ff * f, int32_t track);
 int32_t mp4ff_num_samples(const struct mp4ff *f, int track);
+uint64_t mp4ff_get_duration(const struct mp4ff *f, int32_t track);
 struct mp4ff *mp4ff_open_read_metaonly(struct mp4ff_callback *f);
 
 int mp4ff_meta_get_by_index(const struct mp4ff *f, unsigned int index,