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gstreamer/gst/audioparsers/gstmpegaudioparse.c
Mark Nauwelaerts 8f0e2346c7 mpegaudioparse: add to documentation
2010-12-03 18:23:17 +01:00

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/* GStreamer MPEG audio parser
* Copyright (C) 2006-2007 Jan Schmidt <thaytan@mad.scientist.com>
* Copyright (C) 2010 Mark Nauwelaerts <mnauw users sf net>
* Copyright (C) 2010 Nokia Corporation. All rights reserved.
* Contact: Stefan Kost <stefan.kost@nokia.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:element-mpegaudioparse
* @short_description: MPEG audio parser
* @see_also: #GstAmrParse, #GstAACParse
*
* Parses and frames mpeg1 audio streams. Provides seeking.
*
* <refsect2>
* <title>Example launch line</title>
* |[
* gst-launch filesrc location=test.mp3 ! mpegaudioparse ! mad ! autoaudiosink
* ]|
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "gstmpegaudioparse.h"
#include <gst/base/gstbytereader.h>
GST_DEBUG_CATEGORY_STATIC (mpeg_audio_parse_debug);
#define GST_CAT_DEFAULT mpeg_audio_parse_debug
#define MPEG_AUDIO_CHANNEL_MODE_UNKNOWN -1
#define MPEG_AUDIO_CHANNEL_MODE_STEREO 0
#define MPEG_AUDIO_CHANNEL_MODE_JOINT_STEREO 1
#define MPEG_AUDIO_CHANNEL_MODE_DUAL_CHANNEL 2
#define MPEG_AUDIO_CHANNEL_MODE_MONO 3
#define CRC_UNKNOWN -1
#define CRC_PROTECTED 0
#define CRC_NOT_PROTECTED 1
#define XING_FRAMES_FLAG 0x0001
#define XING_BYTES_FLAG 0x0002
#define XING_TOC_FLAG 0x0004
#define XING_VBR_SCALE_FLAG 0x0008
static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/mpeg, "
"mpegversion = (int) 1, "
"layer = (int) [ 1, 3 ], "
"rate = (int) [ 8000, 48000 ], channels = (int) [ 1, 2 ],"
"parsed=(boolean) true")
);
static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/mpeg, mpegversion = (int) 1, parsed=(boolean)false")
);
static void gst_mpeg_audio_parse_finalize (GObject * object);
static gboolean gst_mpeg_audio_parse_start (GstBaseParse * parse);
static gboolean gst_mpeg_audio_parse_stop (GstBaseParse * parse);
static gboolean gst_mpeg_audio_parse_check_valid_frame (GstBaseParse * parse,
GstBuffer * buffer, guint * size, gint * skipsize);
static GstFlowReturn gst_mpeg_audio_parse_parse_frame (GstBaseParse * parse,
GstBuffer * buf);
static GstFlowReturn gst_mpeg_audio_parse_pre_push_buffer (GstBaseParse * parse,
GstBuffer * buf);
static gboolean gst_mpeg_audio_parse_convert (GstBaseParse * parse,
GstFormat src_format, gint64 src_value,
GstFormat dest_format, gint64 * dest_value);
GST_BOILERPLATE (GstMpegAudioParse, gst_mpeg_audio_parse, GstBaseParse,
GST_TYPE_BASE_PARSE);
#define GST_TYPE_MPEG_AUDIO_CHANNEL_MODE \
(gst_mpeg_audio_channel_mode_get_type())
static const GEnumValue mpeg_audio_channel_mode[] = {
{MPEG_AUDIO_CHANNEL_MODE_UNKNOWN, "Unknown", "unknown"},
{MPEG_AUDIO_CHANNEL_MODE_MONO, "Mono", "mono"},
{MPEG_AUDIO_CHANNEL_MODE_DUAL_CHANNEL, "Dual Channel", "dual-channel"},
{MPEG_AUDIO_CHANNEL_MODE_JOINT_STEREO, "Joint Stereo", "joint-stereo"},
{MPEG_AUDIO_CHANNEL_MODE_STEREO, "Stereo", "stereo"},
{0, NULL, NULL},
};
static GType
gst_mpeg_audio_channel_mode_get_type (void)
{
static GType mpeg_audio_channel_mode_type = 0;
if (!mpeg_audio_channel_mode_type) {
mpeg_audio_channel_mode_type =
g_enum_register_static ("GstMpegAudioChannelMode",
mpeg_audio_channel_mode);
}
return mpeg_audio_channel_mode_type;
}
static const gchar *
gst_mpeg_audio_channel_mode_get_nick (gint mode)
{
guint i;
for (i = 0; i < G_N_ELEMENTS (mpeg_audio_channel_mode); i++) {
if (mpeg_audio_channel_mode[i].value == mode)
return mpeg_audio_channel_mode[i].value_nick;
}
return NULL;
}
static void
gst_mpeg_audio_parse_base_init (gpointer klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sink_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&src_template));
gst_element_class_set_details_simple (element_class, "MPEG1 Audio Parser",
"Codec/Parser/Audio",
"Parses and frames mpeg1 audio streams (levels 1-3), provides seek",
"Jan Schmidt <thaytan@mad.scientist.com>,"
"Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>");
}
static void
gst_mpeg_audio_parse_class_init (GstMpegAudioParseClass * klass)
{
GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GST_DEBUG_CATEGORY_INIT (mpeg_audio_parse_debug, "mpegaudioparse", 0,
"MPEG1 audio stream parser");
object_class->finalize = gst_mpeg_audio_parse_finalize;
parse_class->start = GST_DEBUG_FUNCPTR (gst_mpeg_audio_parse_start);
parse_class->stop = GST_DEBUG_FUNCPTR (gst_mpeg_audio_parse_stop);
parse_class->check_valid_frame =
GST_DEBUG_FUNCPTR (gst_mpeg_audio_parse_check_valid_frame);
parse_class->parse_frame =
GST_DEBUG_FUNCPTR (gst_mpeg_audio_parse_parse_frame);
parse_class->pre_push_buffer =
GST_DEBUG_FUNCPTR (gst_mpeg_audio_parse_pre_push_buffer);
parse_class->convert = GST_DEBUG_FUNCPTR (gst_mpeg_audio_parse_convert);
/* register tags */
#define GST_TAG_CRC "has-crc"
#define GST_TAG_MODE "channel-mode"
gst_tag_register (GST_TAG_CRC, GST_TAG_FLAG_META, G_TYPE_BOOLEAN,
"has crc", "Using CRC", NULL);
gst_tag_register (GST_TAG_MODE, GST_TAG_FLAG_ENCODED, G_TYPE_STRING,
"channel mode", "MPEG audio channel mode", NULL);
g_type_class_ref (GST_TYPE_MPEG_AUDIO_CHANNEL_MODE);
}
static void
gst_mpeg_audio_parse_reset (GstMpegAudioParse * mp3parse)
{
mp3parse->channels = -1;
mp3parse->rate = -1;
mp3parse->sent_codec_tag = FALSE;
mp3parse->last_posted_crc = CRC_UNKNOWN;
mp3parse->last_posted_channel_mode = MPEG_AUDIO_CHANNEL_MODE_UNKNOWN;
mp3parse->xing_flags = 0;
mp3parse->xing_bitrate = 0;
mp3parse->xing_frames = 0;
mp3parse->xing_total_time = 0;
mp3parse->xing_bytes = 0;
mp3parse->xing_vbr_scale = 0;
memset (mp3parse->xing_seek_table, 0, 100);
memset (mp3parse->xing_seek_table_inverse, 0, 256);
mp3parse->vbri_bitrate = 0;
mp3parse->vbri_frames = 0;
mp3parse->vbri_total_time = 0;
mp3parse->vbri_bytes = 0;
mp3parse->vbri_seek_points = 0;
g_free (mp3parse->vbri_seek_table);
mp3parse->vbri_seek_table = NULL;
}
static void
gst_mpeg_audio_parse_init (GstMpegAudioParse * mp3parse,
GstMpegAudioParseClass * klass)
{
gst_mpeg_audio_parse_reset (mp3parse);
}
static void
gst_mpeg_audio_parse_finalize (GObject * object)
{
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static gboolean
gst_mpeg_audio_parse_start (GstBaseParse * parse)
{
GstMpegAudioParse *mp3parse = GST_MPEG_AUDIO_PARSE (parse);
gst_base_parse_set_min_frame_size (GST_BASE_PARSE (mp3parse), 1024);
GST_DEBUG_OBJECT (parse, "starting");
gst_mpeg_audio_parse_reset (mp3parse);
return TRUE;
}
static gboolean
gst_mpeg_audio_parse_stop (GstBaseParse * parse)
{
GstMpegAudioParse *mp3parse = GST_MPEG_AUDIO_PARSE (parse);
GST_DEBUG_OBJECT (parse, "stopping");
gst_mpeg_audio_parse_reset (mp3parse);
return TRUE;
}
static const guint mp3types_bitrates[2][3][16] = {
{
{0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448,},
{0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384,},
{0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,}
},
{
{0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256,},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160,},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160,}
},
};
static const guint mp3types_freqs[3][3] = { {44100, 48000, 32000},
{22050, 24000, 16000},
{11025, 12000, 8000}
};
static inline guint
mp3_type_frame_length_from_header (GstMpegAudioParse * mp3parse, guint32 header,
guint * put_version, guint * put_layer, guint * put_channels,
guint * put_bitrate, guint * put_samplerate, guint * put_mode,
guint * put_crc)
{
guint length;
gulong mode, samplerate, bitrate, layer, channels, padding, crc;
gulong version;
gint lsf, mpg25;
if (header & (1 << 20)) {
lsf = (header & (1 << 19)) ? 0 : 1;
mpg25 = 0;
} else {
lsf = 1;
mpg25 = 1;
}
version = 1 + lsf + mpg25;
layer = 4 - ((header >> 17) & 0x3);
crc = (header >> 16) & 0x1;
bitrate = (header >> 12) & 0xF;
bitrate = mp3types_bitrates[lsf][layer - 1][bitrate] * 1000;
/* The caller has ensured we have a valid header, so bitrate can't be
zero here. */
g_assert (bitrate != 0);
samplerate = (header >> 10) & 0x3;
samplerate = mp3types_freqs[lsf + mpg25][samplerate];
padding = (header >> 9) & 0x1;
mode = (header >> 6) & 0x3;
channels = (mode == 3) ? 1 : 2;
switch (layer) {
case 1:
length = 4 * ((bitrate * 12) / samplerate + padding);
break;
case 2:
length = (bitrate * 144) / samplerate + padding;
break;
default:
case 3:
length = (bitrate * 144) / (samplerate << lsf) + padding;
break;
}
GST_DEBUG_OBJECT (mp3parse, "Calculated mp3 frame length of %u bytes",
length);
GST_DEBUG_OBJECT (mp3parse, "samplerate = %lu, bitrate = %lu, version = %lu, "
"layer = %lu, channels = %lu, mode = %s", samplerate, bitrate, version,
layer, channels, gst_mpeg_audio_channel_mode_get_nick (mode));
if (put_version)
*put_version = version;
if (put_layer)
*put_layer = layer;
if (put_channels)
*put_channels = channels;
if (put_bitrate)
*put_bitrate = bitrate;
if (put_samplerate)
*put_samplerate = samplerate;
if (put_mode)
*put_mode = mode;
if (put_crc)
*put_crc = crc;
return length;
}
/* Minimum number of consecutive, valid-looking frames to consider
* for resyncing */
#define MIN_RESYNC_FRAMES 3
/* Perform extended validation to check that subsequent headers match
* the first header given here in important characteristics, to avoid
* false sync. We look for a minimum of MIN_RESYNC_FRAMES consecutive
* frames to match their major characteristics.
*
* If at_eos is set to TRUE, we just check that we don't find any invalid
* frames in whatever data is available, rather than requiring a full
* MIN_RESYNC_FRAMES of data.
*
* Returns TRUE if we've seen enough data to validate or reject the frame.
* If TRUE is returned, then *valid contains TRUE if it validated, or false
* if we decided it was false sync.
* If FALSE is returned, then *valid contains minimum needed data.
*/
static gboolean
gst_mp3parse_validate_extended (GstMpegAudioParse * mp3parse, GstBuffer * buf,
guint32 header, int bpf, gboolean at_eos, gint * valid)
{
guint32 next_header;
const guint8 *data;
guint available;
int frames_found = 1;
int offset = bpf;
available = GST_BUFFER_SIZE (buf);
data = GST_BUFFER_DATA (buf);
while (frames_found < MIN_RESYNC_FRAMES) {
/* Check if we have enough data for all these frames, plus the next
frame header. */
if (available < offset + 4) {
if (at_eos) {
/* Running out of data at EOS is fine; just accept it */
*valid = TRUE;
return TRUE;
} else {
*valid = offset + 4;
return FALSE;
}
}
next_header = GST_READ_UINT32_BE (data + offset);
GST_DEBUG_OBJECT (mp3parse, "At %d: header=%08X, header2=%08X, bpf=%d",
offset, (unsigned int) header, (unsigned int) next_header, bpf);
/* mask the bits which are allowed to differ between frames */
#define HDRMASK ~((0xF << 12) /* bitrate */ | \
(0x1 << 9) /* padding */ | \
(0xf << 4) /* mode|mode extension */ | \
(0xf)) /* copyright|emphasis */
if ((next_header & HDRMASK) != (header & HDRMASK)) {
/* If any of the unmasked bits don't match, then it's not valid */
GST_DEBUG_OBJECT (mp3parse, "next header doesn't match "
"(header=%08X (%08X), header2=%08X (%08X), bpf=%d)",
(guint) header, (guint) header & HDRMASK, (guint) next_header,
(guint) next_header & HDRMASK, bpf);
*valid = FALSE;
return TRUE;
} else if ((((next_header >> 12) & 0xf) == 0) ||
(((next_header >> 12) & 0xf) == 0xf)) {
/* The essential parts were the same, but the bitrate held an
invalid value - also reject */
GST_DEBUG_OBJECT (mp3parse, "next header invalid (bitrate)");
*valid = FALSE;
return TRUE;
}
bpf = mp3_type_frame_length_from_header (mp3parse, next_header,
NULL, NULL, NULL, NULL, NULL, NULL, NULL);
offset += bpf;
frames_found++;
}
*valid = TRUE;
return TRUE;
}
static gboolean
gst_mpeg_audio_parse_head_check (GstMpegAudioParse * mp3parse,
unsigned long head)
{
GST_DEBUG_OBJECT (mp3parse, "checking mp3 header 0x%08lx", head);
/* if it's not a valid sync */
if ((head & 0xffe00000) != 0xffe00000) {
GST_WARNING_OBJECT (mp3parse, "invalid sync");
return FALSE;
}
/* if it's an invalid MPEG version */
if (((head >> 19) & 3) == 0x1) {
GST_WARNING_OBJECT (mp3parse, "invalid MPEG version: 0x%lx",
(head >> 19) & 3);
return FALSE;
}
/* if it's an invalid layer */
if (!((head >> 17) & 3)) {
GST_WARNING_OBJECT (mp3parse, "invalid layer: 0x%lx", (head >> 17) & 3);
return FALSE;
}
/* if it's an invalid bitrate */
if (((head >> 12) & 0xf) == 0x0) {
GST_WARNING_OBJECT (mp3parse, "invalid bitrate: 0x%lx."
"Free format files are not supported yet", (head >> 12) & 0xf);
return FALSE;
}
if (((head >> 12) & 0xf) == 0xf) {
GST_WARNING_OBJECT (mp3parse, "invalid bitrate: 0x%lx", (head >> 12) & 0xf);
return FALSE;
}
/* if it's an invalid samplerate */
if (((head >> 10) & 0x3) == 0x3) {
GST_WARNING_OBJECT (mp3parse, "invalid samplerate: 0x%lx",
(head >> 10) & 0x3);
return FALSE;
}
if ((head & 0x3) == 0x2) {
/* Ignore this as there are some files with emphasis 0x2 that can
* be played fine. See BGO #537235 */
GST_WARNING_OBJECT (mp3parse, "invalid emphasis: 0x%lx", head & 0x3);
}
return TRUE;
}
static gboolean
gst_mpeg_audio_parse_check_valid_frame (GstBaseParse * parse, GstBuffer * buf,
guint * framesize, gint * skipsize)
{
GstByteReader reader = GST_BYTE_READER_INIT_FROM_BUFFER (buf);
GstMpegAudioParse *mp3parse = GST_MPEG_AUDIO_PARSE (parse);
gint off, bpf;
gboolean sync, drain, valid, caps_change;
guint32 header;
guint bitrate, layer, rate, channels, version, mode, crc;
if (G_UNLIKELY (GST_BUFFER_SIZE (buf) < 6))
return FALSE;
off = gst_byte_reader_masked_scan_uint32 (&reader, 0xffe00000, 0xffe00000,
0, GST_BUFFER_SIZE (buf));
GST_LOG_OBJECT (parse, "possible sync at buffer offset %d", off);
/* didn't find anything that looks like a sync word, skip */
if (off < 0) {
*skipsize = GST_BUFFER_SIZE (buf) - 3;
return FALSE;
}
/* possible frame header, but not at offset 0? skip bytes before sync */
if (off > 0) {
*skipsize = off;
return FALSE;
}
/* make sure the values in the frame header look sane */
header = GST_READ_UINT32_BE (GST_BUFFER_DATA (buf));
if (!gst_mpeg_audio_parse_head_check (mp3parse, header)) {
*skipsize = 1;
return FALSE;
}
GST_LOG_OBJECT (parse, "got frame");
bpf = mp3_type_frame_length_from_header (mp3parse, header,
&version, &layer, &channels, &bitrate, &rate, &mode, &crc);
g_assert (bpf != 0);
if (channels != mp3parse->channels || rate != mp3parse->rate ||
layer != mp3parse->layer || version != mp3parse->version)
caps_change = TRUE;
else
caps_change = FALSE;
sync = gst_base_parse_get_sync (parse);
drain = gst_base_parse_get_drain (parse);
if (!drain && (!sync || caps_change)) {
if (!gst_mp3parse_validate_extended (mp3parse, buf, header, bpf, drain,
&valid)) {
/* not enough data */
gst_base_parse_set_min_frame_size (parse, valid);
*skipsize = 0;
return FALSE;
} else {
if (!valid) {
*skipsize = off + 2;
return FALSE;
}
}
}
*framesize = bpf;
return TRUE;
}
static void
gst_mpeg_audio_parse_handle_first_frame (GstMpegAudioParse * mp3parse,
GstBuffer * buf)
{
const guint32 xing_id = 0x58696e67; /* 'Xing' in hex */
const guint32 info_id = 0x496e666f; /* 'Info' in hex - found in LAME CBR files */
const guint32 vbri_id = 0x56425249; /* 'VBRI' in hex */
gint offset;
guint64 avail;
gint64 upstream_total_bytes = 0;
GstFormat fmt = GST_FORMAT_BYTES;
guint32 read_id;
const guint8 *data;
GstBaseParseSeekable seekable;
guint bitrate;
if (mp3parse->sent_codec_tag)
return;
/* Check first frame for Xing info */
if (mp3parse->version == 1) { /* MPEG-1 file */
if (mp3parse->channels == 1)
offset = 0x11;
else
offset = 0x20;
} else { /* MPEG-2 header */
if (mp3parse->channels == 1)
offset = 0x09;
else
offset = 0x11;
}
/* Skip the 4 bytes of the MP3 header too */
offset += 4;
/* Check if we have enough data to read the Xing header */
avail = GST_BUFFER_SIZE (buf);
data = GST_BUFFER_DATA (buf);
if (avail < offset + 8)
return;
/* The header starts at the provided offset */
data += offset;
/* obtain real upstream total bytes */
fmt = GST_FORMAT_BYTES;
if (!gst_pad_query_peer_duration (GST_BASE_PARSE_SINK_PAD (GST_BASE_PARSE
(mp3parse)), &fmt, &upstream_total_bytes))
upstream_total_bytes = 0;
read_id = GST_READ_UINT32_BE (data);
if (read_id == xing_id || read_id == info_id) {
guint32 xing_flags;
guint bytes_needed = offset + 8;
gint64 total_bytes;
GstClockTime total_time;
GST_DEBUG_OBJECT (mp3parse, "Found Xing header marker 0x%x", xing_id);
/* Read 4 base bytes of flags, big-endian */
xing_flags = GST_READ_UINT32_BE (data + 4);
if (xing_flags & XING_FRAMES_FLAG)
bytes_needed += 4;
if (xing_flags & XING_BYTES_FLAG)
bytes_needed += 4;
if (xing_flags & XING_TOC_FLAG)
bytes_needed += 100;
if (xing_flags & XING_VBR_SCALE_FLAG)
bytes_needed += 4;
if (avail < bytes_needed) {
GST_DEBUG_OBJECT (mp3parse,
"Not enough data to read Xing header (need %d)", bytes_needed);
return;
}
GST_DEBUG_OBJECT (mp3parse, "Reading Xing header");
mp3parse->xing_flags = xing_flags;
data = GST_BUFFER_DATA (buf);
data += offset + 8;
if (xing_flags & XING_FRAMES_FLAG) {
mp3parse->xing_frames = GST_READ_UINT32_BE (data);
if (mp3parse->xing_frames == 0) {
GST_WARNING_OBJECT (mp3parse,
"Invalid number of frames in Xing header");
mp3parse->xing_flags &= ~XING_FRAMES_FLAG;
} else {
mp3parse->xing_total_time = gst_util_uint64_scale (GST_SECOND,
(guint64) (mp3parse->xing_frames) * (mp3parse->spf),
mp3parse->rate);
}
data += 4;
} else {
mp3parse->xing_frames = 0;
mp3parse->xing_total_time = 0;
}
if (xing_flags & XING_BYTES_FLAG) {
mp3parse->xing_bytes = GST_READ_UINT32_BE (data);
if (mp3parse->xing_bytes == 0) {
GST_WARNING_OBJECT (mp3parse, "Invalid number of bytes in Xing header");
mp3parse->xing_flags &= ~XING_BYTES_FLAG;
}
data += 4;
} else {
mp3parse->xing_bytes = 0;
}
/* If we know the upstream size and duration, compute the
* total bitrate, rounded up to the nearest kbit/sec */
if ((total_time = mp3parse->xing_total_time) &&
(total_bytes = mp3parse->xing_bytes)) {
mp3parse->xing_bitrate = gst_util_uint64_scale (total_bytes,
8 * GST_SECOND, total_time);
mp3parse->xing_bitrate += 500;
mp3parse->xing_bitrate -= mp3parse->xing_bitrate % 1000;
}
if (xing_flags & XING_TOC_FLAG) {
int i, percent = 0;
guchar *table = mp3parse->xing_seek_table;
guchar old = 0, new;
guint first;
first = data[0];
GST_DEBUG_OBJECT (mp3parse,
"Subtracting initial offset of %d bytes from Xing TOC", first);
/* xing seek table: percent time -> 1/256 bytepos */
for (i = 0; i < 100; i++) {
new = data[i] - first;
if (old > new) {
GST_WARNING_OBJECT (mp3parse, "Skipping broken Xing TOC");
mp3parse->xing_flags &= ~XING_TOC_FLAG;
goto skip_toc;
}
mp3parse->xing_seek_table[i] = old = new;
}
/* build inverse table: 1/256 bytepos -> 1/100 percent time */
for (i = 0; i < 256; i++) {
while (percent < 99 && table[percent + 1] <= i)
percent++;
if (table[percent] == i) {
mp3parse->xing_seek_table_inverse[i] = percent * 100;
} else if (table[percent] < i && percent < 99) {
gdouble fa, fb, fx;
gint a = percent, b = percent + 1;
fa = table[a];
fb = table[b];
fx = (b - a) / (fb - fa) * (i - fa) + a;
mp3parse->xing_seek_table_inverse[i] = (guint16) (fx * 100);
} else if (percent == 99) {
gdouble fa, fb, fx;
gint a = percent, b = 100;
fa = table[a];
fb = 256.0;
fx = (b - a) / (fb - fa) * (i - fa) + a;
mp3parse->xing_seek_table_inverse[i] = (guint16) (fx * 100);
}
}
skip_toc:
data += 100;
} else {
memset (mp3parse->xing_seek_table, 0, 100);
memset (mp3parse->xing_seek_table_inverse, 0, 256);
}
if (xing_flags & XING_VBR_SCALE_FLAG) {
mp3parse->xing_vbr_scale = GST_READ_UINT32_BE (data);
} else
mp3parse->xing_vbr_scale = 0;
GST_DEBUG_OBJECT (mp3parse, "Xing header reported %u frames, time %"
GST_TIME_FORMAT ", %u bytes, vbr scale %u", mp3parse->xing_frames,
GST_TIME_ARGS (mp3parse->xing_total_time), mp3parse->xing_bytes,
mp3parse->xing_vbr_scale);
/* check for truncated file */
if (upstream_total_bytes && mp3parse->xing_bytes &&
mp3parse->xing_bytes * 0.8 > upstream_total_bytes) {
GST_WARNING_OBJECT (mp3parse, "File appears to have been truncated; "
"invalidating Xing header duration and size");
mp3parse->xing_flags &= ~XING_BYTES_FLAG;
mp3parse->xing_flags &= ~XING_FRAMES_FLAG;
}
} else if (read_id == vbri_id) {
gint64 total_bytes, total_frames;
GstClockTime total_time;
guint16 nseek_points;
GST_DEBUG_OBJECT (mp3parse, "Found VBRI header marker 0x%x", vbri_id);
if (avail < offset + 26) {
GST_DEBUG_OBJECT (mp3parse,
"Not enough data to read VBRI header (need %d)", offset + 26);
return;
}
GST_DEBUG_OBJECT (mp3parse, "Reading VBRI header");
data = GST_BUFFER_DATA (buf);
data += offset + 4;
if (GST_READ_UINT16_BE (data) != 0x0001) {
GST_WARNING_OBJECT (mp3parse,
"Unsupported VBRI version 0x%x", GST_READ_UINT16_BE (data));
return;
}
data += 2;
/* Skip encoder delay */
data += 2;
/* Skip quality */
data += 2;
total_bytes = GST_READ_UINT32_BE (data);
if (total_bytes != 0)
mp3parse->vbri_bytes = total_bytes;
data += 4;
total_frames = GST_READ_UINT32_BE (data);
if (total_frames != 0) {
mp3parse->vbri_frames = total_frames;
mp3parse->vbri_total_time = gst_util_uint64_scale (GST_SECOND,
(guint64) (mp3parse->vbri_frames) * (mp3parse->spf), mp3parse->rate);
}
data += 4;
/* If we know the upstream size and duration, compute the
* total bitrate, rounded up to the nearest kbit/sec */
if ((total_time = mp3parse->vbri_total_time) &&
(total_bytes = mp3parse->vbri_bytes)) {
mp3parse->vbri_bitrate = gst_util_uint64_scale (total_bytes,
8 * GST_SECOND, total_time);
mp3parse->vbri_bitrate += 500;
mp3parse->vbri_bitrate -= mp3parse->vbri_bitrate % 1000;
}
nseek_points = GST_READ_UINT16_BE (data);
data += 2;
if (nseek_points > 0) {
guint scale, seek_bytes, seek_frames;
gint i;
mp3parse->vbri_seek_points = nseek_points;
scale = GST_READ_UINT16_BE (data);
data += 2;
seek_bytes = GST_READ_UINT16_BE (data);
data += 2;
seek_frames = GST_READ_UINT16_BE (data);
if (scale == 0 || seek_bytes == 0 || seek_bytes > 4 || seek_frames == 0) {
GST_WARNING_OBJECT (mp3parse, "Unsupported VBRI seek table");
goto out_vbri;
}
if (avail < offset + 26 + nseek_points * seek_bytes) {
GST_WARNING_OBJECT (mp3parse,
"Not enough data to read VBRI seek table (need %d)",
offset + 26 + nseek_points * seek_bytes);
goto out_vbri;
}
if (seek_frames * nseek_points < total_frames - seek_frames ||
seek_frames * nseek_points > total_frames + seek_frames) {
GST_WARNING_OBJECT (mp3parse,
"VBRI seek table doesn't cover the complete file");
goto out_vbri;
}
if (avail < offset + 26) {
GST_DEBUG_OBJECT (mp3parse,
"Not enough data to read VBRI header (need %d)",
offset + 26 + nseek_points * seek_bytes);
return;
}
data = GST_BUFFER_DATA (buf);
data += offset + 26;
/* VBRI seek table: frame/seek_frames -> byte */
mp3parse->vbri_seek_table = g_new (guint32, nseek_points);
if (seek_bytes == 4)
for (i = 0; i < nseek_points; i++) {
mp3parse->vbri_seek_table[i] = GST_READ_UINT32_BE (data) * scale;
data += 4;
} else if (seek_bytes == 3)
for (i = 0; i < nseek_points; i++) {
mp3parse->vbri_seek_table[i] = GST_READ_UINT24_BE (data) * scale;
data += 3;
} else if (seek_bytes == 2)
for (i = 0; i < nseek_points; i++) {
mp3parse->vbri_seek_table[i] = GST_READ_UINT16_BE (data) * scale;
data += 2;
} else /* seek_bytes == 1 */
for (i = 0; i < nseek_points; i++) {
mp3parse->vbri_seek_table[i] = GST_READ_UINT8 (data) * scale;
data += 1;
}
}
out_vbri:
GST_DEBUG_OBJECT (mp3parse, "VBRI header reported %u frames, time %"
GST_TIME_FORMAT ", bytes %u", mp3parse->vbri_frames,
GST_TIME_ARGS (mp3parse->vbri_total_time), mp3parse->vbri_bytes);
/* check for truncated file */
if (upstream_total_bytes && mp3parse->vbri_bytes &&
mp3parse->vbri_bytes * 0.8 > upstream_total_bytes) {
GST_WARNING_OBJECT (mp3parse, "File appears to have been truncated; "
"invalidating VBRI header duration and size");
mp3parse->vbri_valid = FALSE;
} else {
mp3parse->vbri_valid = TRUE;
}
} else {
GST_DEBUG_OBJECT (mp3parse,
"Xing, LAME or VBRI header not found in first frame");
}
/* set duration if tables provided a valid one */
if (mp3parse->xing_flags & XING_FRAMES_FLAG) {
gst_base_parse_set_duration (GST_BASE_PARSE (mp3parse), GST_FORMAT_TIME,
mp3parse->xing_total_time, 0);
}
if (mp3parse->vbri_total_time != 0 && mp3parse->vbri_valid) {
gst_base_parse_set_duration (GST_BASE_PARSE (mp3parse), GST_FORMAT_TIME,
mp3parse->vbri_total_time, 0);
}
/* tell baseclass how nicely we can seek, and a bitrate if one found */
seekable = GST_BASE_PARSE_SEEK_DEFAULT;
if ((mp3parse->xing_flags & XING_TOC_FLAG) && mp3parse->xing_bytes &&
mp3parse->xing_total_time)
seekable = GST_BASE_PARSE_SEEK_TABLE;
if (mp3parse->vbri_seek_table && mp3parse->vbri_bytes &&
mp3parse->vbri_total_time)
seekable = GST_BASE_PARSE_SEEK_TABLE;
if (mp3parse->xing_bitrate)
bitrate = mp3parse->xing_bitrate;
else if (mp3parse->vbri_bitrate)
bitrate = mp3parse->vbri_bitrate;
else
bitrate = 0;
gst_base_parse_set_seek (GST_BASE_PARSE (mp3parse), seekable, bitrate);
}
static GstFlowReturn
gst_mpeg_audio_parse_parse_frame (GstBaseParse * parse, GstBuffer * buf)
{
GstMpegAudioParse *mp3parse = GST_MPEG_AUDIO_PARSE (parse);
guint bitrate, layer, rate, channels, version, mode, crc;
g_return_val_if_fail (GST_BUFFER_SIZE (buf) >= 4, GST_FLOW_ERROR);
if (!mp3_type_frame_length_from_header (mp3parse,
GST_READ_UINT32_BE (GST_BUFFER_DATA (buf)),
&version, &layer, &channels, &bitrate, &rate, &mode, &crc))
goto broken_header;
if (G_UNLIKELY (channels != mp3parse->channels || rate != mp3parse->rate ||
layer != mp3parse->layer || version != mp3parse->version)) {
GstCaps *caps = gst_caps_new_simple ("audio/mpeg",
"mpegversion", G_TYPE_INT, 1,
"mpegaudioversion", G_TYPE_INT, version,
"layer", G_TYPE_INT, layer,
"rate", G_TYPE_INT, rate,
"channels", G_TYPE_INT, channels, "parsed", G_TYPE_BOOLEAN, TRUE, NULL);
gst_buffer_set_caps (buf, caps);
gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (parse), caps);
gst_caps_unref (caps);
mp3parse->rate = rate;
mp3parse->channels = channels;
mp3parse->layer = layer;
mp3parse->version = version;
/* see http://www.codeproject.com/audio/MPEGAudioInfo.asp */
if (mp3parse->layer == 1)
mp3parse->spf = 384;
else if (mp3parse->layer == 2)
mp3parse->spf = 1152;
else if (mp3parse->version == 1) {
mp3parse->spf = 1152;
} else {
/* MPEG-2 or "2.5" */
mp3parse->spf = 576;
}
/* lead_in:
* We start pushing 9 frames earlier (29 frames for MPEG2) than
* segment start to be able to decode the first frame we want.
* 9 (29) frames are the theoretical maximum of frames that contain
* data for the current frame (bit reservoir).
*
* lead_out:
* Some mp3 streams have an offset in the timestamps, for which we have to
* push the frame *after* the end position in order for the decoder to be
* able to decode everything up until the segment.stop position. */
gst_base_parse_set_frame_props (parse, mp3parse->rate, mp3parse->spf,
(version == 1) ? 10 : 30, 2);
}
/* For first frame; check for seek tables and output a codec tag */
gst_mpeg_audio_parse_handle_first_frame (mp3parse, buf);
/* store some frame info for later processing */
mp3parse->last_crc = crc;
mp3parse->last_mode = mode;
return GST_FLOW_OK;
/* ERRORS */
broken_header:
{
/* this really shouldn't ever happen */
GST_ELEMENT_ERROR (parse, STREAM, DECODE, (NULL), (NULL));
return GST_FLOW_ERROR;
}
}
static gboolean
gst_mpeg_audio_parse_time_to_bytepos (GstMpegAudioParse * mp3parse,
GstClockTime ts, gint64 * bytepos)
{
gint64 total_bytes;
GstClockTime total_time;
/* If XING seek table exists use this for time->byte conversion */
if ((mp3parse->xing_flags & XING_TOC_FLAG) &&
(total_bytes = mp3parse->xing_bytes) &&
(total_time = mp3parse->xing_total_time)) {
gdouble fa, fb, fx;
gdouble percent =
CLAMP ((100.0 * gst_util_guint64_to_gdouble (ts)) /
gst_util_guint64_to_gdouble (total_time), 0.0, 100.0);
gint index = CLAMP (percent, 0, 99);
fa = mp3parse->xing_seek_table[index];
if (index < 99)
fb = mp3parse->xing_seek_table[index + 1];
else
fb = 256.0;
fx = fa + (fb - fa) * (percent - index);
*bytepos = (1.0 / 256.0) * fx * total_bytes;
return TRUE;
}
if (mp3parse->vbri_seek_table && (total_bytes = mp3parse->vbri_bytes) &&
(total_time = mp3parse->vbri_total_time)) {
gint i, j;
gdouble a, b, fa, fb;
i = gst_util_uint64_scale (ts, mp3parse->vbri_seek_points - 1, total_time);
i = CLAMP (i, 0, mp3parse->vbri_seek_points - 1);
a = gst_guint64_to_gdouble (gst_util_uint64_scale (i, total_time,
mp3parse->vbri_seek_points));
fa = 0.0;
for (j = i; j >= 0; j--)
fa += mp3parse->vbri_seek_table[j];
if (i + 1 < mp3parse->vbri_seek_points) {
b = gst_guint64_to_gdouble (gst_util_uint64_scale (i + 1, total_time,
mp3parse->vbri_seek_points));
fb = fa + mp3parse->vbri_seek_table[i + 1];
} else {
b = gst_guint64_to_gdouble (total_time);
fb = total_bytes;
}
*bytepos = fa + ((fb - fa) / (b - a)) * (gst_guint64_to_gdouble (ts) - a);
return TRUE;
}
return FALSE;
}
static gboolean
gst_mpeg_audio_parse_bytepos_to_time (GstMpegAudioParse * mp3parse,
gint64 bytepos, GstClockTime * ts)
{
gint64 total_bytes;
GstClockTime total_time;
/* If XING seek table exists use this for byte->time conversion */
if ((mp3parse->xing_flags & XING_TOC_FLAG) &&
(total_bytes = mp3parse->xing_bytes) &&
(total_time = mp3parse->xing_total_time)) {
gdouble fa, fb, fx;
gdouble pos;
gint index;
pos = CLAMP ((bytepos * 256.0) / total_bytes, 0.0, 256.0);
index = CLAMP (pos, 0, 255);
fa = mp3parse->xing_seek_table_inverse[index];
if (index < 255)
fb = mp3parse->xing_seek_table_inverse[index + 1];
else
fb = 10000.0;
fx = fa + (fb - fa) * (pos - index);
*ts = (1.0 / 10000.0) * fx * gst_util_guint64_to_gdouble (total_time);
return TRUE;
}
if (mp3parse->vbri_seek_table &&
(total_bytes = mp3parse->vbri_bytes) &&
(total_time = mp3parse->vbri_total_time)) {
gint i = 0;
guint64 sum = 0;
gdouble a, b, fa, fb;
do {
sum += mp3parse->vbri_seek_table[i];
i++;
} while (i + 1 < mp3parse->vbri_seek_points
&& sum + mp3parse->vbri_seek_table[i] < bytepos);
i--;
a = gst_guint64_to_gdouble (sum);
fa = gst_guint64_to_gdouble (gst_util_uint64_scale (i, total_time,
mp3parse->vbri_seek_points));
if (i + 1 < mp3parse->vbri_seek_points) {
b = a + mp3parse->vbri_seek_table[i + 1];
fb = gst_guint64_to_gdouble (gst_util_uint64_scale (i + 1, total_time,
mp3parse->vbri_seek_points));
} else {
b = total_bytes;
fb = gst_guint64_to_gdouble (total_time);
}
*ts = gst_gdouble_to_guint64 (fa + ((fb - fa) / (b - a)) * (bytepos - a));
return TRUE;
}
return FALSE;
}
static gboolean
gst_mpeg_audio_parse_convert (GstBaseParse * parse, GstFormat src_format,
gint64 src_value, GstFormat dest_format, gint64 * dest_value)
{
GstMpegAudioParse *mp3parse = GST_MPEG_AUDIO_PARSE (parse);
gboolean res = FALSE;
if (src_format == GST_FORMAT_TIME && dest_format == GST_FORMAT_BYTES)
res =
gst_mpeg_audio_parse_time_to_bytepos (mp3parse, src_value, dest_value);
else if (src_format == GST_FORMAT_BYTES && dest_format == GST_FORMAT_TIME)
res = gst_mpeg_audio_parse_bytepos_to_time (mp3parse, src_value,
(GstClockTime *) dest_value);
/* if no tables, fall back to default estimated rate based conversion */
if (!res)
return gst_base_parse_convert_default (parse, src_format, src_value,
dest_format, dest_value);
return res;
}
static GstFlowReturn
gst_mpeg_audio_parse_pre_push_buffer (GstBaseParse * parse, GstBuffer * buf)
{
GstMpegAudioParse *mp3parse = GST_MPEG_AUDIO_PARSE (parse);
GstTagList *taglist;
/* tag sending done late enough in hook to ensure pending events
* have already been sent */
if (!mp3parse->sent_codec_tag) {
gchar *codec;
/* codec tag */
if (mp3parse->layer == 3) {
codec = g_strdup_printf ("MPEG %d Audio, Layer %d (MP3)",
mp3parse->version, mp3parse->layer);
} else {
codec = g_strdup_printf ("MPEG %d Audio, Layer %d",
mp3parse->version, mp3parse->layer);
}
taglist = gst_tag_list_new ();
gst_tag_list_add (taglist, GST_TAG_MERGE_REPLACE,
GST_TAG_AUDIO_CODEC, codec, NULL);
gst_element_found_tags_for_pad (GST_ELEMENT (mp3parse),
GST_BASE_PARSE_SRC_PAD (mp3parse), taglist);
g_free (codec);
/* also signals the end of first-frame processing */
mp3parse->sent_codec_tag = TRUE;
}
/* we will create a taglist (if any of the parameters has changed)
* to add the tags that changed */
taglist = NULL;
if (mp3parse->last_posted_crc != mp3parse->last_crc) {
gboolean using_crc;
if (!taglist) {
taglist = gst_tag_list_new ();
}
mp3parse->last_posted_crc = mp3parse->last_crc;
if (mp3parse->last_posted_crc == CRC_PROTECTED) {
using_crc = TRUE;
} else {
using_crc = FALSE;
}
gst_tag_list_add (taglist, GST_TAG_MERGE_REPLACE, GST_TAG_CRC,
using_crc, NULL);
}
if (mp3parse->last_posted_channel_mode != mp3parse->last_mode) {
if (!taglist) {
taglist = gst_tag_list_new ();
}
mp3parse->last_posted_channel_mode = mp3parse->last_mode;
gst_tag_list_add (taglist, GST_TAG_MERGE_REPLACE, GST_TAG_MODE,
gst_mpeg_audio_channel_mode_get_nick (mp3parse->last_mode), NULL);
}
/* if the taglist exists, we need to send it */
if (taglist) {
gst_element_found_tags_for_pad (GST_ELEMENT (mp3parse),
GST_BASE_PARSE_SRC_PAD (mp3parse), taglist);
}
/* usual clipping applies */
return GST_BASE_PARSE_FLOW_CLIP;
}
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