diff options
Diffstat (limited to 'lib/rbcodec/metadata/mp4.c')
| -rw-r--r-- | lib/rbcodec/metadata/mp4.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/lib/rbcodec/metadata/mp4.c b/lib/rbcodec/metadata/mp4.c index 7686165a0d..1540e93738 100644 --- a/lib/rbcodec/metadata/mp4.c +++ b/lib/rbcodec/metadata/mp4.c @@ -213,6 +213,7 @@ static bool read_mp4_esds(int fd, struct mp3entry* id3, uint32_t* size) { unsigned char buf[8] = {0}; bool sbr = false; + bool sbr_signaled = false; lseek(fd, 4, SEEK_CUR); /* Version and flags. */ read(fd, buf, 1); /* Verify ES_DescrTag. */ @@ -282,6 +283,7 @@ static bool read_mp4_esds(int fd, struct mp3entry* id3, uint32_t* size) * Object type - 5 bits * Frequency index - 4 bits * Channel configuration - 4 bits + * Also see libfaad/mp4.c AudioSpecificConfig2 (consider using it instead of manual parsing) */ bits = get_long_be(buf); type = bits >> 27; /* Object type - 5 bits */ @@ -326,6 +328,7 @@ static bool read_mp4_esds(int fd, struct mp3entry* id3, uint32_t* size) if (type == 5) { sbr = bits >> 31; + sbr_signaled = true; if (sbr) { @@ -353,13 +356,11 @@ static bool read_mp4_esds(int fd, struct mp3entry* id3, uint32_t* size) } } - if (!sbr && (id3->frequency <= 24000) && (length <= 2)) + if (!sbr && !sbr_signaled && id3->frequency <= 24000) { - /* Double the frequency for low-frequency files without a "long" - * DecSpecificConfig header. The file may or may not contain SBR, - * but here we guess it does if the header is short. This can - * fail on some files, but it's the best we can do, short of - * decoding (parts of) the file. + /* As stated in libfaad/mp4.c AudioSpecificConfig2: + * no SBR signalled, this could mean either implicit signalling or no SBR in this file + * MPEG specification states: assume SBR on files with samplerate <= 24000 Hz */ id3->frequency *= 2; sbr = true; |