gstreamer/gst/videoparsers/gstmpegvideoparse.c
Edward Hervey c27b16bfe3 videoparsers: Speed up the start code search algorithm
Based on 96a7f9c8b1

Makes it 3-4 times faster
2011-06-12 12:55:40 +02:00

703 lines
21 KiB
C

/* GStreamer
* Copyright (C) <2007> Jan Schmidt <thaytan@mad.scientist.com>
* Copyright (C) <2011> Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
* Copyright (C) <2011> Collabora Multimedia
* Copyright (C) <2011> Nokia Corporation
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <gst/base/gstbytereader.h>
#include "gstmpegvideoparse.h"
GST_DEBUG_CATEGORY (mpegv_parse_debug);
#define GST_CAT_DEFAULT mpegv_parse_debug
static GstStaticPadTemplate src_template =
GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/mpeg, "
"mpegversion = (int) [1, 2], "
"parsed = (boolean) true, " "systemstream = (boolean) false")
);
static GstStaticPadTemplate sink_template =
GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/mpeg, "
"mpegversion = (int) [1, 2], "
"parsed = (boolean) false, " "systemstream = (boolean) false")
);
/* Properties */
#define DEFAULT_PROP_DROP TRUE
#define DEFAULT_PROP_GOP_SPLIT FALSE
enum
{
PROP_0,
PROP_DROP,
PROP_GOP_SPLIT,
PROP_LAST
};
GST_BOILERPLATE (GstMpegvParse, gst_mpegv_parse, GstBaseParse,
GST_TYPE_BASE_PARSE);
static gboolean gst_mpegv_parse_start (GstBaseParse * parse);
static gboolean gst_mpegv_parse_stop (GstBaseParse * parse);
static gboolean gst_mpegv_parse_check_valid_frame (GstBaseParse * parse,
GstBaseParseFrame * frame, guint * framesize, gint * skipsize);
static GstFlowReturn gst_mpegv_parse_parse_frame (GstBaseParse * parse,
GstBaseParseFrame * frame);
static gboolean gst_mpegv_parse_set_caps (GstBaseParse * parse, GstCaps * caps);
static void gst_mpegv_parse_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_mpegv_parse_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void
gst_mpegv_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 (&src_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sink_template));
gst_element_class_set_details_simple (element_class,
"MPEG video elementary stream parser",
"Codec/Parser/Video",
"Parses and frames MPEG-1 and MPEG-2 elementary video streams",
"Wim Taymans <wim.taymans@ccollabora.co.uk>, "
"Jan Schmidt <thaytan@mad.scientist.com>, "
"Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>");
GST_DEBUG_CATEGORY_INIT (mpegv_parse_debug, "mpegvideoparse", 0,
"MPEG-1/2 video parser");
}
static void
gst_mpegv_parse_set_property (GObject * object, guint property_id,
const GValue * value, GParamSpec * pspec)
{
GstMpegvParse *parse = GST_MPEGVIDEO_PARSE (object);
switch (property_id) {
case PROP_DROP:
parse->drop = g_value_get_boolean (value);
break;
case PROP_GOP_SPLIT:
parse->gop_split = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
}
}
static void
gst_mpegv_parse_get_property (GObject * object, guint property_id,
GValue * value, GParamSpec * pspec)
{
GstMpegvParse *parse = GST_MPEGVIDEO_PARSE (object);
switch (property_id) {
case PROP_DROP:
g_value_set_boolean (value, parse->drop);
break;
case PROP_GOP_SPLIT:
g_value_set_boolean (value, parse->gop_split);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
}
}
static void
gst_mpegv_parse_class_init (GstMpegvParseClass * klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
parent_class = g_type_class_peek_parent (klass);
gobject_class->set_property = gst_mpegv_parse_set_property;
gobject_class->get_property = gst_mpegv_parse_get_property;
g_object_class_install_property (gobject_class, PROP_DROP,
g_param_spec_boolean ("drop", "drop",
"Drop data untill valid configuration data is received either "
"in the stream or through caps", DEFAULT_PROP_DROP,
G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_GOP_SPLIT,
g_param_spec_boolean ("gop-split", "gop-split",
"Split frame when encountering GOP", DEFAULT_PROP_GOP_SPLIT,
G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/* Override BaseParse vfuncs */
parse_class->start = GST_DEBUG_FUNCPTR (gst_mpegv_parse_start);
parse_class->stop = GST_DEBUG_FUNCPTR (gst_mpegv_parse_stop);
parse_class->check_valid_frame =
GST_DEBUG_FUNCPTR (gst_mpegv_parse_check_valid_frame);
parse_class->parse_frame = GST_DEBUG_FUNCPTR (gst_mpegv_parse_parse_frame);
parse_class->set_sink_caps = GST_DEBUG_FUNCPTR (gst_mpegv_parse_set_caps);
}
static void
gst_mpegv_parse_init (GstMpegvParse * parse, GstMpegvParseClass * g_class)
{
}
static void
gst_mpegv_parse_reset_frame (GstMpegvParse * mpvparse)
{
/* done parsing; reset state */
mpvparse->last_sc = -1;
mpvparse->seq_offset = -1;
mpvparse->pic_offset = -1;
}
static void
gst_mpegv_parse_reset (GstMpegvParse * mpvparse)
{
gst_mpegv_parse_reset_frame (mpvparse);
mpvparse->profile = 0;
mpvparse->update_caps = TRUE;
gst_buffer_replace (&mpvparse->config, NULL);
memset (&mpvparse->params, 0, sizeof (mpvparse->params));
}
static gboolean
gst_mpegv_parse_start (GstBaseParse * parse)
{
GstMpegvParse *mpvparse = GST_MPEGVIDEO_PARSE (parse);
GST_DEBUG_OBJECT (parse, "start");
gst_mpegv_parse_reset (mpvparse);
/* at least this much for a valid frame */
gst_base_parse_set_min_frame_size (parse, 6);
return TRUE;
}
static gboolean
gst_mpegv_parse_stop (GstBaseParse * parse)
{
GstMpegvParse *mpvparse = GST_MPEGVIDEO_PARSE (parse);
GST_DEBUG_OBJECT (parse, "stop");
gst_mpegv_parse_reset (mpvparse);
return TRUE;
}
static gboolean
gst_mpegv_parse_process_config (GstMpegvParse * mpvparse, const guint8 * data,
gsize size)
{
/* only do stuff if something new */
if (mpvparse->config && size == GST_BUFFER_SIZE (mpvparse->config) &&
memcmp (GST_BUFFER_DATA (mpvparse->config), data, size) == 0)
return TRUE;
if (!gst_mpeg_video_params_parse_config (&mpvparse->params, data, size)) {
GST_DEBUG_OBJECT (mpvparse, "failed to parse config data (size %"
G_GSSIZE_FORMAT ")", size);
return FALSE;
}
GST_LOG_OBJECT (mpvparse, "accepting parsed config size %" G_GSSIZE_FORMAT,
size);
/* parsing ok, so accept it as new config */
if (mpvparse->config != NULL)
gst_buffer_unref (mpvparse->config);
mpvparse->config = gst_buffer_new_and_alloc (size);
memcpy (GST_BUFFER_DATA (mpvparse->config), data, size);
/* trigger src caps update */
mpvparse->update_caps = TRUE;
return TRUE;
}
#ifndef GST_DISABLE_GST_DEBUG
static const gchar *
picture_start_code_name (guint8 psc)
{
guint i;
const struct
{
guint8 psc;
const gchar *name;
} psc_names[] = {
{
0x00, "Picture Start"}, {
0xb0, "Reserved"}, {
0xb1, "Reserved"}, {
0xb2, "User Data Start"}, {
0xb3, "Sequence Header Start"}, {
0xb4, "Sequence Error"}, {
0xb5, "Extension Start"}, {
0xb6, "Reserved"}, {
0xb7, "Sequence End"}, {
0xb8, "Group Start"}, {
0xb9, "Program End"}
};
if (psc < 0xB0 && psc > 0)
return "Slice Start";
for (i = 0; i < G_N_ELEMENTS (psc_names); i++)
if (psc_names[i].psc == psc)
return psc_names[i].name;
return "UNKNOWN";
};
static const gchar *
picture_type_name (guint8 pct)
{
guint i;
const struct
{
guint8 pct;
const gchar *name;
} pct_names[] = {
{
0, "Forbidden"}, {
1, "I Frame"}, {
2, "P Frame"}, {
3, "B Frame"}, {
4, "DC Intra Coded (Shall Not Be Used!)"}
};
for (i = 0; i < G_N_ELEMENTS (pct_names); i++)
if (pct_names[i].pct == pct)
return pct_names[i].name;
return "Reserved/Unknown";
}
#endif /* GST_DISABLE_GST_DEBUG */
/* caller guarantees at least start code in @buf at @off */
/* for off == 0 initial code; returns TRUE if code starts a frame,
* otherwise returns TRUE if code terminates preceding frame */
static gboolean
gst_mpegv_parse_process_sc (GstMpegvParse * mpvparse, GstBuffer * buf, gint off)
{
gboolean ret = FALSE, do_seq = TRUE;
guint8 *data;
guint code;
g_return_val_if_fail (buf && GST_BUFFER_SIZE (buf) >= 4, FALSE);
data = GST_BUFFER_DATA (buf);
code = data[off + 3];
GST_LOG_OBJECT (mpvparse, "process startcode %x (%s)", code,
picture_start_code_name (code));
switch (code) {
case MPEG_PACKET_PICTURE:
GST_LOG_OBJECT (mpvparse, "startcode is PICTURE");
/* picture is aggregated with preceding sequence/gop, if any.
* so, picture start code only ends if already a previous one */
if (mpvparse->pic_offset < 0)
mpvparse->pic_offset = off;
else
ret = TRUE;
if (!off)
ret = TRUE;
break;
case MPEG_PACKET_SEQUENCE:
GST_LOG_OBJECT (mpvparse, "startcode is SEQUENCE");
if (off == 0)
mpvparse->seq_offset = off;
ret = TRUE;
break;
case MPEG_PACKET_GOP:
GST_LOG_OBJECT (mpvparse, "startcode is GOP");
if (mpvparse->seq_offset >= 0)
ret = mpvparse->gop_split;
else
ret = TRUE;
break;
default:
do_seq = FALSE;
break;
}
/* process config data */
if (G_UNLIKELY (mpvparse->seq_offset >= 0 && off && do_seq)) {
g_assert (mpvparse->seq_offset == 0);
gst_mpegv_parse_process_config (mpvparse, GST_BUFFER_DATA (buf), off);
/* avoid accepting again for a PICTURE sc following a GOP sc */
mpvparse->seq_offset = -1;
}
/* extract some picture info if there is any in the frame being terminated */
if (G_UNLIKELY (ret && off)) {
if (G_LIKELY (mpvparse->pic_offset >= 0 && mpvparse->pic_offset < off)) {
if (G_LIKELY (GST_BUFFER_SIZE (buf) >= mpvparse->pic_offset + 6)) {
gint pct = (data[mpvparse->pic_offset + 5] >> 3) & 0x7;
GST_LOG_OBJECT (mpvparse, "picture_coding_type %d (%s)", pct,
picture_type_name (pct));
mpvparse->intra_frame = (pct == MPEG_PICTURE_TYPE_I);
} else {
GST_WARNING_OBJECT (mpvparse, "no data following PICTURE startcode");
mpvparse->intra_frame = FALSE;
}
} else {
/* frame without picture must be some config, consider as keyframe */
mpvparse->intra_frame = TRUE;
}
GST_LOG_OBJECT (mpvparse, "ending frame of size %d, is intra %d", off,
mpvparse->intra_frame);
}
return ret;
}
static inline guint
scan_for_start_codes (const GstByteReader * reader, guint offset, guint size)
{
const guint8 *data;
guint32 state;
guint i;
g_return_val_if_fail (size > 0, -1);
g_return_val_if_fail ((guint64) offset + size <= reader->size - reader->byte,
-1);
/* we can't find the pattern with less than 4 bytes */
if (G_UNLIKELY (size < 4))
return -1;
data = reader->data + reader->byte + offset;
/* set the state to something that does not match */
state = 0xffffffff;
/* now find data */
for (i = 0; i < size; i++) {
/* throw away one byte and move in the next byte */
state = ((state << 8) | data[i]);
if (G_UNLIKELY ((state & 0xffffff00) == 0x00000100)) {
/* we have a match but we need to have skipped at
* least 4 bytes to fill the state. */
if (G_LIKELY (i >= 3))
return offset + i - 3;
}
/* Accelerate search for start code */
if (data[i] > 1) {
while (i < (size - 4) && data[i] > 1) {
if (data[i + 3] > 1)
i += 4;
else
i += 1;
}
state = 0x00000100;
}
}
/* nothing found */
return -1;
}
/* FIXME move into baseparse, or anything equivalent;
* see https://bugzilla.gnome.org/show_bug.cgi?id=650093 */
#define GST_BASE_PARSE_FRAME_FLAG_PARSING 0x10000
static gboolean
gst_mpegv_parse_check_valid_frame (GstBaseParse * parse,
GstBaseParseFrame * frame, guint * framesize, gint * skipsize)
{
GstMpegvParse *mpvparse = GST_MPEGVIDEO_PARSE (parse);
GstBuffer *buf = frame->buffer;
GstByteReader reader = GST_BYTE_READER_INIT_FROM_BUFFER (buf);
gint off = 0;
gboolean ret;
retry:
/* at least start code and subsequent byte */
if (G_UNLIKELY (GST_BUFFER_SIZE (buf) - off < 5))
return FALSE;
/* avoid stale cached parsing state */
if (!(frame->flags & GST_BASE_PARSE_FRAME_FLAG_PARSING)) {
GST_LOG_OBJECT (mpvparse, "parsing new frame");
gst_mpegv_parse_reset_frame (mpvparse);
frame->flags |= GST_BASE_PARSE_FRAME_FLAG_PARSING;
} else {
GST_LOG_OBJECT (mpvparse, "resuming frame parsing");
}
/* if already found a previous start code, e.g. start of frame, go for next */
if (mpvparse->last_sc >= 0) {
off = mpvparse->last_sc;
goto next;
}
off = scan_for_start_codes (&reader, off, GST_BUFFER_SIZE (buf) - off);
GST_LOG_OBJECT (mpvparse, "possible sync at buffer offset %d", off);
/* didn't find anything that looks like a sync word, skip */
if (G_UNLIKELY (off < 0)) {
*skipsize = GST_BUFFER_SIZE (buf) - 3;
return FALSE;
}
/* possible frame header, but not at offset 0? skip bytes before sync */
if (G_UNLIKELY (off > 0)) {
*skipsize = off;
return FALSE;
}
/* note: initial start code is assumed at offset 0 by subsequent code */
/* examine start code, see if it looks like an initial start code */
if (gst_mpegv_parse_process_sc (mpvparse, buf, 0)) {
/* found sc */
mpvparse->last_sc = 0;
} else {
off++;
goto retry;
}
next:
/* start is fine as of now */
*skipsize = 0;
/* position a bit further than last sc */
off++;
/* so now we have start code at start of data; locate next start code */
off = scan_for_start_codes (&reader, off, GST_BUFFER_SIZE (buf) - off);
GST_LOG_OBJECT (mpvparse, "next start code at %d", off);
if (off < 0) {
/* if draining, take all */
if (GST_BASE_PARSE_DRAINING (parse)) {
off = GST_BUFFER_SIZE (buf);
ret = TRUE;
} else {
/* resume scan where we left it */
mpvparse->last_sc = GST_BUFFER_SIZE (buf) - 4;
/* request best next available */
*framesize = G_MAXUINT;
return FALSE;
}
} else {
/* decide whether this startcode ends a frame */
ret = gst_mpegv_parse_process_sc (mpvparse, buf, off);
}
if (ret) {
*framesize = off;
} else {
goto next;
}
return ret;
}
static void
gst_mpegv_parse_update_src_caps (GstMpegvParse * mpvparse)
{
GstCaps *caps = NULL;
/* only update if no src caps yet or explicitly triggered */
if (G_LIKELY (GST_PAD_CAPS (GST_BASE_PARSE_SRC_PAD (mpvparse)) &&
!mpvparse->update_caps))
return;
/* carry over input caps as much as possible; override with our own stuff */
caps = GST_PAD_CAPS (GST_BASE_PARSE_SINK_PAD (mpvparse));
if (caps) {
caps = gst_caps_copy (caps);
} else {
caps = gst_caps_new_simple ("video/mpeg", NULL);
}
/* typically we don't output buffers until we have properly parsed some
* config data, so we should at least know about version.
* If not, it means it has been requested not to drop data, and
* upstream and/or app must know what they are doing ... */
if (G_LIKELY (mpvparse->params.mpeg_version))
gst_caps_set_simple (caps,
"mpegversion", G_TYPE_INT, mpvparse->params.mpeg_version, NULL);
gst_caps_set_simple (caps, "systemstream", G_TYPE_BOOLEAN, FALSE,
"parsed", G_TYPE_BOOLEAN, TRUE, NULL);
if (mpvparse->params.width > 0 && mpvparse->params.height > 0) {
gst_caps_set_simple (caps, "width", G_TYPE_INT, mpvparse->params.width,
"height", G_TYPE_INT, mpvparse->params.height, NULL);
}
/* perhaps we have a framerate */
if (mpvparse->params.fps_n > 0 && mpvparse->params.fps_d > 0) {
gint fps_num = mpvparse->params.fps_n;
gint fps_den = mpvparse->params.fps_d;
GstClockTime latency = gst_util_uint64_scale (GST_SECOND, fps_den, fps_num);
gst_caps_set_simple (caps, "framerate",
GST_TYPE_FRACTION, fps_num, fps_den, NULL);
gst_base_parse_set_frame_rate (GST_BASE_PARSE (mpvparse),
fps_num, fps_den, 0, 0);
gst_base_parse_set_latency (GST_BASE_PARSE (mpvparse), latency, latency);
}
/* or pixel-aspect-ratio */
if (mpvparse->params.par_w && mpvparse->params.par_h > 0) {
gst_caps_set_simple (caps, "pixel-aspect-ratio", GST_TYPE_FRACTION,
mpvparse->params.par_w, mpvparse->params.par_h, NULL);
}
if (mpvparse->config != NULL) {
gst_caps_set_simple (caps, "codec_data",
GST_TYPE_BUFFER, mpvparse->config, NULL);
}
if (mpvparse->params.mpeg_version == 2) {
const guint profile_c = mpvparse->params.profile;
const guint level_c = mpvparse->params.level;
const gchar *profile = NULL, *level = NULL;
/*
* Profile indication - 1 => High, 2 => Spatially Scalable,
* 3 => SNR Scalable, 4 => Main, 5 => Simple
* 4:2:2 and Multi-view have profile = 0, with the escape bit set to 1
*/
const gchar *profiles[] = { "high", "spatial", "snr", "main", "simple" };
/*
* Level indication - 4 => High, 6 => High-1440, 8 => Main, 10 => Low,
* except in the case of profile = 0
*/
const gchar *levels[] = { "high", "high-1440", "main", "low" };
if (profile_c > 0 && profile_c < 6)
profile = profiles[profile_c - 1];
if ((level_c > 3) && (level_c < 11) && (level_c % 2 == 0))
level = levels[(level_c >> 1) - 1];
if (profile_c == 8) {
/* Non-hierarchical profile */
switch (level_c) {
case 2:
level = levels[0];
case 5:
level = levels[2];
profile = "4:2:2";
break;
case 10:
level = levels[0];
case 11:
level = levels[1];
case 13:
level = levels[2];
case 14:
level = levels[3];
profile = "multiview";
break;
default:
break;
}
}
/* FIXME does it make sense to expose profile/level in the caps ? */
if (profile)
gst_caps_set_simple (caps, "profile", G_TYPE_STRING, profile, NULL);
else
GST_DEBUG_OBJECT (mpvparse, "Invalid profile - %u", profile_c);
if (level)
gst_caps_set_simple (caps, "level", G_TYPE_STRING, level, NULL);
else
GST_DEBUG_OBJECT (mpvparse, "Invalid level - %u", level_c);
}
gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (mpvparse), caps);
gst_caps_unref (caps);
}
static GstFlowReturn
gst_mpegv_parse_parse_frame (GstBaseParse * parse, GstBaseParseFrame * frame)
{
GstMpegvParse *mpvparse = GST_MPEGVIDEO_PARSE (parse);
GstBuffer *buffer = frame->buffer;
gst_mpegv_parse_update_src_caps (mpvparse);
if (G_UNLIKELY (mpvparse->intra_frame))
GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DELTA_UNIT);
else
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT);
/* maybe only sequence in this buffer, though not recommended,
* so mark it as such and force 0 duration */
if (G_UNLIKELY (mpvparse->pic_offset < 0)) {
GST_DEBUG_OBJECT (mpvparse, "frame holds no picture data");
frame->flags |= GST_BASE_PARSE_FRAME_FLAG_NO_FRAME;
GST_BUFFER_DURATION (buffer) = 0;
}
if (G_UNLIKELY (mpvparse->drop && !mpvparse->config)) {
GST_DEBUG_OBJECT (mpvparse, "dropping frame as no config yet");
return GST_BASE_PARSE_FLOW_DROPPED;
} else
return GST_FLOW_OK;
}
static gboolean
gst_mpegv_parse_set_caps (GstBaseParse * parse, GstCaps * caps)
{
GstMpegvParse *mpvparse = GST_MPEGVIDEO_PARSE (parse);
GstStructure *s;
const GValue *value;
GstBuffer *buf;
GST_DEBUG_OBJECT (parse, "setcaps called with %" GST_PTR_FORMAT, caps);
s = gst_caps_get_structure (caps, 0);
if ((value = gst_structure_get_value (s, "codec_data")) != NULL
&& (buf = gst_value_get_buffer (value))) {
/* best possible parse attempt,
* src caps are based on sink caps so it will end up in there
* whether sucessful or not */
gst_mpegv_parse_process_config (mpvparse, GST_BUFFER_DATA (buf),
GST_BUFFER_SIZE (buf));
}
/* let's not interfere and accept regardless of config parsing success */
return TRUE;
}