/**
* gst_bit_reader_init_from_buffer:
* @reader: a #GstBitReader instance
* @buffer: (transfer none): Buffer from which the #GstBitReader should read
*
* Initializes a #GstBitReader instance to read from @buffer. This function
* can be called on already initialized instances.
*
* Since: 0.10.22
*/
void
gst_bit_reader_init_from_buffer (GstBitReader * reader,
const GstBuffer * buffer)
{
g_return_if_fail (GST_IS_BUFFER (buffer));
gst_bit_reader_init (reader, GST_BUFFER_DATA (buffer),
GST_BUFFER_SIZE (buffer));
}
static gboolean
gst_ac3_parse_frame_header (GstAc3Parse * parse, GstBuffer * buf, gint skip,
guint * framesize, guint * rate, guint * chans, guint * blocks,
guint * sid, gboolean * eac)
{
GstBitReader bits;
guint16 sync;
guint8 bsid;
GstMapInfo map;
gboolean ret = FALSE;
gst_buffer_map (buf, &map, GST_MAP_READ);
gst_bit_reader_init (&bits, map.data, map.size);
GST_MEMDUMP_OBJECT (parse, "AC3 frame sync", map.data, MIN (map.size, 16));
gst_bit_reader_skip_unchecked (&bits, skip * 8);
sync = gst_bit_reader_get_bits_uint16_unchecked (&bits, 16);
gst_bit_reader_skip_unchecked (&bits, 16 + 8);
bsid = gst_bit_reader_peek_bits_uint8_unchecked (&bits, 5);
if (G_UNLIKELY (sync != 0x0b77))
goto cleanup;
GST_LOG_OBJECT (parse, "bsid = %d", bsid);
if (bsid <= 10) {
if (eac)
*eac = FALSE;
ret = gst_ac3_parse_frame_header_ac3 (parse, buf, skip, framesize, rate,
chans, blocks, sid);
goto cleanup;
} else if (bsid <= 16) {
if (eac)
*eac = TRUE;
ret = gst_ac3_parse_frame_header_eac3 (parse, buf, skip, framesize, rate,
chans, blocks, sid);
goto cleanup;
} else {
GST_DEBUG_OBJECT (parse, "unexpected bsid %d", bsid);
ret = FALSE;
goto cleanup;
}
GST_DEBUG_OBJECT (parse, "unexpected bsid %d", bsid);
cleanup:
gst_buffer_unmap (buf, &map);
return ret;
}
static gboolean
gst_ac3_parse_frame_header_ac3 (GstAc3Parse * ac3parse, GstBuffer * buf,
gint skip, guint * frame_size, guint * rate, guint * chans, guint * blks,
guint * sid)
{
GstBitReader bits;
GstMapInfo map;
guint8 fscod, frmsizcod, bsid, acmod, lfe_on, rate_scale;
gboolean ret = FALSE;
GST_LOG_OBJECT (ac3parse, "parsing ac3");
gst_buffer_map (buf, &map, GST_MAP_READ);
gst_bit_reader_init (&bits, map.data, map.size);
gst_bit_reader_skip_unchecked (&bits, skip * 8);
gst_bit_reader_skip_unchecked (&bits, 16 + 16);
fscod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2);
frmsizcod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 6);
if (G_UNLIKELY (fscod == 3 || frmsizcod >= G_N_ELEMENTS (frmsizcod_table))) {
GST_DEBUG_OBJECT (ac3parse, "bad fscod=%d frmsizcod=%d", fscod, frmsizcod);
goto cleanup;
}
bsid = gst_bit_reader_get_bits_uint8_unchecked (&bits, 5);
gst_bit_reader_skip_unchecked (&bits, 3); /* bsmod */
acmod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 3);
/* spec not quite clear here: decoder should decode if less than 8,
* but seemingly only defines 6 and 8 cases */
/* Files with 9 and 10 happen, and seem to comply with the <= 8
format, so let them through. The spec says nothing about 9 and 10 */
if (bsid > 10) {
GST_DEBUG_OBJECT (ac3parse, "unexpected bsid=%d", bsid);
goto cleanup;
} else if (bsid != 8 && bsid != 6) {
GST_DEBUG_OBJECT (ac3parse, "undefined bsid=%d", bsid);
}
if ((acmod & 0x1) && (acmod != 0x1)) /* 3 front channels */
gst_bit_reader_skip_unchecked (&bits, 2);
if ((acmod & 0x4)) /* if a surround channel exists */
gst_bit_reader_skip_unchecked (&bits, 2);
if (acmod == 0x2) /* if in 2/0 mode */
gst_bit_reader_skip_unchecked (&bits, 2);
lfe_on = gst_bit_reader_get_bits_uint8_unchecked (&bits, 1);
/* 6/8->0, 9->1, 10->2,
see http://matroska.org/technical/specs/codecid/index.html */
rate_scale = (CLAMP (bsid, 8, 10) - 8);
if (frame_size)
*frame_size = frmsizcod_table[frmsizcod].frame_size[fscod] * 2;
if (rate)
*rate = fscod_rates[fscod] >> rate_scale;
if (chans)
*chans = acmod_chans[acmod] + lfe_on;
if (blks)
*blks = 6;
if (sid)
*sid = 0;
ret = TRUE;
cleanup:
gst_buffer_unmap (buf, &map);
return ret;
}
static gboolean
gst_ac3_parse_frame_header_eac3 (GstAc3Parse * ac3parse, GstBuffer * buf,
gint skip, guint * frame_size, guint * rate, guint * chans, guint * blks,
guint * sid)
{
GstBitReader bits;
GstMapInfo map;
guint16 frmsiz, sample_rate, blocks;
guint8 strmtyp, fscod, fscod2, acmod, lfe_on, strmid, numblkscod;
gboolean ret = FALSE;
GST_LOG_OBJECT (ac3parse, "parsing e-ac3");
gst_buffer_map (buf, &map, GST_MAP_READ);
gst_bit_reader_init (&bits, map.data, map.size);
gst_bit_reader_skip_unchecked (&bits, skip * 8);
gst_bit_reader_skip_unchecked (&bits, 16);
strmtyp = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* strmtyp */
if (G_UNLIKELY (strmtyp == 3)) {
GST_DEBUG_OBJECT (ac3parse, "bad strmtyp %d", strmtyp);
goto cleanup;
}
strmid = gst_bit_reader_get_bits_uint8_unchecked (&bits, 3); /* substreamid */
frmsiz = gst_bit_reader_get_bits_uint16_unchecked (&bits, 11); /* frmsiz */
fscod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* fscod */
if (fscod == 3) {
fscod2 = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* fscod2 */
if (G_UNLIKELY (fscod2 == 3)) {
GST_DEBUG_OBJECT (ac3parse, "invalid fscod2");
goto cleanup;
}
sample_rate = fscod_rates[fscod2] / 2;
blocks = 6;
} else {
numblkscod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 2); /* numblkscod */
sample_rate = fscod_rates[fscod];
blocks = numblks[numblkscod];
}
acmod = gst_bit_reader_get_bits_uint8_unchecked (&bits, 3); /* acmod */
lfe_on = gst_bit_reader_get_bits_uint8_unchecked (&bits, 1); /* lfeon */
gst_bit_reader_skip_unchecked (&bits, 5); /* bsid */
if (frame_size)
*frame_size = (frmsiz + 1) * 2;
if (rate)
*rate = sample_rate;
if (chans)
*chans = acmod_chans[acmod] + lfe_on;
if (blks)
*blks = blocks;
if (sid)
*sid = (strmtyp & 0x1) << 3 | strmid;
ret = TRUE;
cleanup:
gst_buffer_unmap (buf, &map);
return ret;
}
static gboolean
gst_rtp_mp4g_pay_parse_audio_config (GstRtpMP4GPay * rtpmp4gpay,
GstBuffer * buffer)
{
GstMapInfo map;
guint8 objectType = 0;
guint8 samplingIdx = 0;
guint8 channelCfg = 0;
GstBitReader br;
gst_buffer_map (buffer, &map, GST_MAP_READ);
gst_bit_reader_init (&br, map.data, map.size);
/* any object type is fine, we need to copy it to the profile-level-id field. */
if (!gst_bit_reader_get_bits_uint8 (&br, &objectType, 5))
goto too_short;
if (objectType == 0)
goto invalid_object;
if (!gst_bit_reader_get_bits_uint8 (&br, &samplingIdx, 4))
goto too_short;
/* only fixed values for now */
if (samplingIdx > 12 && samplingIdx != 15)
goto wrong_freq;
if (!gst_bit_reader_get_bits_uint8 (&br, &channelCfg, 4))
goto too_short;
if (channelCfg > 7)
goto wrong_channels;
/* rtp rate depends on sampling rate of the audio */
if (samplingIdx == 15) {
guint32 rate = 0;
/* index of 15 means we get the rate in the next 24 bits */
if (!gst_bit_reader_get_bits_uint32 (&br, &rate, 24))
goto too_short;
rtpmp4gpay->rate = rate;
} else {
/* else use the rate from the table */
rtpmp4gpay->rate = sampling_table[samplingIdx];
}
rtpmp4gpay->frame_len = 1024;
switch (objectType) {
case 1:
case 2:
case 3:
case 4:
case 6:
case 7:
{
guint8 frameLenFlag = 0;
if (gst_bit_reader_get_bits_uint8 (&br, &frameLenFlag, 1))
if (frameLenFlag)
rtpmp4gpay->frame_len = 960;
break;
}
default:
break;
}
/* extra rtp params contain the number of channels */
g_free (rtpmp4gpay->params);
rtpmp4gpay->params = g_strdup_printf ("%d", channelCfg);
/* audio stream type */
rtpmp4gpay->streamtype = "5";
/* mode only high bitrate for now */
rtpmp4gpay->mode = "AAC-hbr";
/* profile */
g_free (rtpmp4gpay->profile);
rtpmp4gpay->profile = g_strdup_printf ("%d", objectType);
GST_DEBUG_OBJECT (rtpmp4gpay,
"objectType: %d, samplingIdx: %d (%d), channelCfg: %d, frame_len %d",
objectType, samplingIdx, rtpmp4gpay->rate, channelCfg,
rtpmp4gpay->frame_len);
gst_buffer_unmap (buffer, &map);
return TRUE;
/* ERROR */
too_short:
{
GST_ELEMENT_ERROR (rtpmp4gpay, STREAM, FORMAT,
(NULL), ("config string too short"));
gst_buffer_unmap (buffer, &map);
return FALSE;
}
invalid_object:
{
GST_ELEMENT_ERROR (rtpmp4gpay, STREAM, FORMAT,
(NULL), ("invalid object type"));
gst_buffer_unmap (buffer, &map);
return FALSE;
}
wrong_freq:
{
GST_ELEMENT_ERROR (rtpmp4gpay, STREAM, NOT_IMPLEMENTED,
(NULL), ("unsupported frequency index %d", samplingIdx));
gst_buffer_unmap (buffer, &map);
return FALSE;
}
wrong_channels:
{
GST_ELEMENT_ERROR (rtpmp4gpay, STREAM, NOT_IMPLEMENTED,
(NULL), ("unsupported number of channels %d, must < 8", channelCfg));
gst_buffer_unmap (buffer, &map);
return FALSE;
}
}
