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typefinding: look for dts frames at non-zero offsets too

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Scan a bit into the data when checking for dts frames instead
of expecting the frame sync to be right at the start of the
data. This is needed for some dts-disguised-as-pcm-in-wav files.

See #413942.
This commit is contained in:
Tim-Philipp Müller 2010-06-11 12:34:24 +01:00
parent 9235c91bec
commit b5a7e96291
1 changed files with 66 additions and 37 deletions
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103
gst/typefind/gsttypefindfunctions.c
View file

@ -1261,9 +1261,12 @@ ac3_type_find (GstTypeFind * tf, gpointer unused)
/*** audio/x-dts ***/
static GstStaticCaps dts_caps = GST_STATIC_CAPS ("audio/x-dts");
#define DTS_CAPS (gst_static_caps_get (&dts_caps))
#define DTS_MIN_FRAMESIZE 96
#define DTS_MAX_FRAMESIZE 18725 /* 16384*16/14 */
static void
dts_type_find (GstTypeFind * tf, gpointer unused)
static gboolean
dts_parse_frame_header (DataScanCtx * c, guint * frame_size,
guint * sample_rate, guint * channels)
{
static const int sample_rates[16] = { 0, 8000, 16000, 32000, 0, 0, 11025,
22050, 44100, 0, 0, 12000, 24000, 48000, 96000, 192000
@ -1271,39 +1274,31 @@ dts_type_find (GstTypeFind * tf, gpointer unused)
static const guint8 channels_table[16] = { 1, 2, 2, 2, 2, 3, 3, 4, 4, 5,
6, 6, 6, 7, 8, 8
};
GstTypeFindProbability prob;
const guint8 *data;
guint16 hdr[8];
guint32 marker;
guint sample_rate, num_blocks, frame_size, chans, lfe, i;
guint num_blocks, chans, lfe, i;
data = gst_type_find_peek (tf, 0, sizeof (hdr));
if (data == NULL)
return;
marker = GST_READ_UINT32_BE (data);
marker = GST_READ_UINT32_BE (c->data);
/* raw big endian or 14-bit big endian */
if (marker == 0x7FFE8001 || marker == 0x1FFFE800) {
for (i = 0; i < G_N_ELEMENTS (hdr); ++i)
hdr[i] = GST_READ_UINT16_BE (data + (i * sizeof (guint16)));
hdr[i] = GST_READ_UINT16_BE (c->data + (i * sizeof (guint16)));
} else
/* raw little endian or 14-bit little endian */
if (marker == 0xFE7F0180 || marker == 0xFF1F00E8) {
for (i = 0; i < G_N_ELEMENTS (hdr); ++i)
hdr[i] = GST_READ_UINT16_LE (data + (i * sizeof (guint16)));
hdr[i] = GST_READ_UINT16_LE (c->data + (i * sizeof (guint16)));
} else {
return;
return FALSE;
}
GST_LOG ("dts sync marker 0x%08x at offset 0", marker);
prob = GST_TYPE_FIND_LIKELY;
GST_LOG ("dts sync marker 0x%08x at offset %u", marker, (guint) c->offset);
/* 14-bit mode */
if (marker == 0x1FFFE800 || marker == 0xFF1F00E8) {
if ((hdr[2] & 0xFFF0) != 0x07F0)
return;
return FALSE;
/* discard top 2 bits (2 void), shift in 2 */
hdr[0] = (hdr[0] << 2) | ((hdr[1] >> 12) & 0x0003);
/* discard top 4 bits (2 void, 2 shifted into hdr[0]), shift in 4 etc. */
@ -1314,38 +1309,72 @@ dts_type_find (GstTypeFind * tf, gpointer unused)
hdr[5] = (hdr[5] << 12) | ((hdr[6] >> 2) & 0x0FFF);
hdr[6] = (hdr[6] << 14) | ((hdr[7] >> 0) & 0x3FFF);
g_assert (hdr[0] == 0x7FFE && hdr[1] == 0x8001);
prob = GST_TYPE_FIND_NEARLY_CERTAIN;
}
GST_LOG ("frame header: %04x%04x%04x%04x", hdr[2], hdr[3], hdr[4], hdr[5]);
num_blocks = (hdr[2] >> 2) & 0x7F;
frame_size = (((hdr[2] & 0x03) << 12) | (hdr[3] >> 4)) + 1;
*frame_size = (((hdr[2] & 0x03) << 12) | (hdr[3] >> 4)) + 1;
chans = ((hdr[3] & 0x0F) << 2) | (hdr[4] >> 14);
sample_rate = sample_rates[(hdr[4] >> 10) & 0x0F];
*sample_rate = sample_rates[(hdr[4] >> 10) & 0x0F];
lfe = (hdr[5] >> 9) & 0x03;
if (num_blocks < 5 || frame_size < 96 || sample_rate == 0)
return;
if (num_blocks < 5 || *frame_size < 96 || *sample_rate == 0)
return FALSE;
/* check for second frame sync */
if (marker == 0x1FFFE800 || marker == 0xFF1F00E8)
frame_size = (frame_size * 16) / 14;
*frame_size = (*frame_size * 16) / 14; /* FIXME: round up? */
if ((data = gst_type_find_peek (tf, frame_size, 4))) {
GST_LOG ("frame size: %u 0x%04x", frame_size, frame_size);
GST_MEMDUMP ("second frame sync", data, 4);
if (GST_READ_UINT32_BE (data) == marker)
prob = GST_TYPE_FIND_MAXIMUM;
}
if (chans < G_N_ELEMENTS (channels_table))
*channels = channels_table[chans] + ((lfe) ? 1 : 0);
else
*channels = 0;
if (chans < G_N_ELEMENTS (channels_table)) {
gst_type_find_suggest_simple (tf, prob, "audio/x-dts",
"rate", G_TYPE_INT, sample_rate,
"channels", G_TYPE_INT, channels_table[chans] + ((lfe) ? 1 : 0), NULL);
} else {
gst_type_find_suggest_simple (tf, prob, "audio/x-dts",
"rate", G_TYPE_INT, sample_rate, NULL);
return TRUE;
}
static void
dts_type_find (GstTypeFind * tf, gpointer unused)
{
DataScanCtx c = { 0, NULL, 0 };
/* Search for an dts frame; not neccesarily right at the start, but give it
* a lower probability if not found right at the start. Check that the
* frame is followed by a second frame at the expected offset. */
while (c.offset <= DTS_MAX_FRAMESIZE) {
guint frame_size, rate, chans;
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, DTS_MIN_FRAMESIZE)))
return;
if (G_UNLIKELY (dts_parse_frame_header (&c, &frame_size, &rate, &chans))) {
GstTypeFindProbability prob;
DataScanCtx next_c;
prob = (c.offset == 0) ? GST_TYPE_FIND_LIKELY : GST_TYPE_FIND_POSSIBLE;
/* check for second frame sync */
next_c = c;
data_scan_ctx_advance (tf, &next_c, frame_size);
if (data_scan_ctx_ensure_data (tf, &next_c, 4)) {
GST_LOG ("frame size: %u 0x%04x", frame_size, frame_size);
GST_MEMDUMP ("second frame sync", next_c.data, 4);
if (GST_READ_UINT32_BE (c.data) == GST_READ_UINT32_BE (next_c.data))
prob = GST_TYPE_FIND_MAXIMUM;
}
if (chans > 0) {
gst_type_find_suggest_simple (tf, prob, "audio/x-dts",
"rate", G_TYPE_INT, rate, "channels", G_TYPE_INT, chans, NULL);
} else {
gst_type_find_suggest_simple (tf, prob, "audio/x-dts",
"rate", G_TYPE_INT, rate, NULL);
}
return;
}
data_scan_ctx_advance (tf, &c, 1);
}
}