/* FIXME: for our purposes it's probably enough to just check for the sync
* marker - we just want to know if it's a header frame or not */
static gboolean
gst_flac_dec_scan_got_frame (GstFlacDec * flacdec, guint8 * data, guint size,
gint64 * last_sample_num)
{
guint headerlen;
guint sr_from_end = 0; /* can be 0, 8 or 16 */
guint bs_from_end = 0; /* can be 0, 8 or 16 */
guint32 val = 0;
guint8 bs, sr, ca, ss, pb;
if (size < 10)
return FALSE;
/* sync */
if (data[0] != 0xFF || (data[1] & 0xFC) != 0xF8)
return FALSE;
if (data[1] & 1) {
GST_WARNING_OBJECT (flacdec, "Variable block size FLAC unsupported");
return FALSE;
}
bs = (data[2] & 0xF0) >> 4; /* blocksize marker */
sr = (data[2] & 0x0F); /* samplerate marker */
ca = (data[3] & 0xF0) >> 4; /* channel assignment */
ss = (data[3] & 0x0F) >> 1; /* sample size marker */
pb = (data[3] & 0x01); /* padding bit */
GST_LOG_OBJECT (flacdec,
"got sync, bs=%x,sr=%x,ca=%x,ss=%x,pb=%x", bs, sr, ca, ss, pb);
if (bs == 0 || sr == 0x0F || ca >= 0x0B || ss == 0x03 || ss == 0x07) {
return FALSE;
}
/* read block size from end of header? */
if (bs == 6)
bs_from_end = 8;
else if (bs == 7)
bs_from_end = 16;
/* read sample rate from end of header? */
if (sr == 0x0C)
sr_from_end = 8;
else if (sr == 0x0D || sr == 0x0E)
sr_from_end = 16;
val = data[4];
/* This is slightly faster than a loop */
if (!(val & 0x80)) {
val = 0;
} else if ((val & 0xc0) && !(val & 0x20)) {
val = 1;
} else if ((val & 0xe0) && !(val & 0x10)) {
val = 2;
} else if ((val & 0xf0) && !(val & 0x08)) {
val = 3;
} else if ((val & 0xf8) && !(val & 0x04)) {
val = 4;
} else if ((val & 0xfc) && !(val & 0x02)) {
val = 5;
} else if ((val & 0xfe) && !(val & 0x01)) {
val = 6;
} else {
GST_LOG_OBJECT (flacdec, "failed to read sample/frame");
return FALSE;
}
val++;
headerlen = 4 + val + (bs_from_end / 8) + (sr_from_end / 8);
if (gst_flac_calculate_crc8 (data, headerlen) != data[headerlen]) {
GST_LOG_OBJECT (flacdec, "invalid checksum");
return FALSE;
}
if (!last_sample_num)
return TRUE;
/* FIXME: This is can be 36 bit if variable block size is used,
* fortunately not encoder supports this yet and we check for that
* above.
*/
val = (guint32) g_utf8_get_char_validated ((gchar *) data + 4, -1);
if (val == (guint32) - 1 || val == (guint32) - 2) {
GST_LOG_OBJECT (flacdec, "failed to read sample/frame");
return FALSE;
}
if (flacdec->min_blocksize == flacdec->max_blocksize) {
*last_sample_num = (val + 1) * flacdec->min_blocksize;
} else {
*last_sample_num = 0; /* FIXME: + length of last block in samples */
}
/* FIXME: only valid for fixed block size streams */
GST_DEBUG_OBJECT (flacdec, "frame number: %" G_GINT64_FORMAT,
*last_sample_num);
if (flacdec->info.rate > 0 && *last_sample_num != 0) {
GST_DEBUG_OBJECT (flacdec, "last sample %" G_GINT64_FORMAT " = %"
GST_TIME_FORMAT, *last_sample_num,
GST_TIME_ARGS (*last_sample_num * GST_SECOND / flacdec->info.rate));
}
return TRUE;
}
/* FIXME: for our purposes it's probably enough to just check for the sync
* marker - we just want to know if it's a header frame or not */
static gboolean
gst_flac_dec_scan_got_frame (GstFlacDec * flacdec, const guint8 * data,
guint size)
{
guint headerlen;
guint sr_from_end = 0; /* can be 0, 8 or 16 */
guint bs_from_end = 0; /* can be 0, 8 or 16 */
guint32 val = 0;
guint8 bs, sr, ca, ss, pb;
gboolean vbs;
if (size < 10)
return FALSE;
/* sync */
if (data[0] != 0xFF || (data[1] & 0xFC) != 0xF8)
return FALSE;
vbs = ! !(data[1] & 1); /* variable blocksize */
bs = (data[2] & 0xF0) >> 4; /* blocksize marker */
sr = (data[2] & 0x0F); /* samplerate marker */
ca = (data[3] & 0xF0) >> 4; /* channel assignment */
ss = (data[3] & 0x0F) >> 1; /* sample size marker */
pb = (data[3] & 0x01); /* padding bit */
GST_LOG_OBJECT (flacdec,
"got sync, vbs=%d,bs=%x,sr=%x,ca=%x,ss=%x,pb=%x", vbs, bs, sr, ca, ss,
pb);
if (bs == 0 || sr == 0x0F || ca >= 0x0B || ss == 0x03 || ss == 0x07) {
return FALSE;
}
/* read block size from end of header? */
if (bs == 6)
bs_from_end = 8;
else if (bs == 7)
bs_from_end = 16;
/* read sample rate from end of header? */
if (sr == 0x0C)
sr_from_end = 8;
else if (sr == 0x0D || sr == 0x0E)
sr_from_end = 16;
val = data[4];
/* This is slightly faster than a loop */
if (!(val & 0x80)) {
val = 0;
} else if ((val & 0xc0) && !(val & 0x20)) {
val = 1;
} else if ((val & 0xe0) && !(val & 0x10)) {
val = 2;
} else if ((val & 0xf0) && !(val & 0x08)) {
val = 3;
} else if ((val & 0xf8) && !(val & 0x04)) {
val = 4;
} else if ((val & 0xfc) && !(val & 0x02)) {
val = 5;
} else if ((val & 0xfe) && !(val & 0x01)) {
val = 6;
} else {
GST_LOG_OBJECT (flacdec, "failed to read sample/frame");
return FALSE;
}
val++;
headerlen = 4 + val + (bs_from_end / 8) + (sr_from_end / 8);
if (gst_flac_calculate_crc8 (data, headerlen) != data[headerlen]) {
GST_LOG_OBJECT (flacdec, "invalid checksum");
return FALSE;
}
return TRUE;
}
