gstreamer/gst/matroska/ebml-write.c
Linus Svensson 0690bd1b21 matroskamux: Use nanosecond precision for DateUTC
DateUTC is specified with nanosecond precision in matroska, make use of
that.
2019-11-22 16:30:50 +01:00

941 lines
23 KiB
C

/* GStreamer EBML I/O
* (c) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
* (c) 2005 Michal Benes <michal.benes@xeris.cz>
*
* ebml-write.c: write EBML data to file/stream
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "ebml-write.h"
#include "ebml-ids.h"
GST_DEBUG_CATEGORY_STATIC (gst_ebml_write_debug);
#define GST_CAT_DEFAULT gst_ebml_write_debug
#define _do_init \
GST_DEBUG_CATEGORY_INIT (gst_ebml_write_debug, "ebmlwrite", 0, "Write EBML structured data")
#define parent_class gst_ebml_write_parent_class
G_DEFINE_TYPE_WITH_CODE (GstEbmlWrite, gst_ebml_write, GST_TYPE_OBJECT,
_do_init);
static void gst_ebml_write_finalize (GObject * object);
static void
gst_ebml_write_class_init (GstEbmlWriteClass * klass)
{
GObjectClass *object = G_OBJECT_CLASS (klass);
object->finalize = gst_ebml_write_finalize;
}
static void
gst_ebml_write_init (GstEbmlWrite * ebml)
{
ebml->srcpad = NULL;
ebml->pos = 0;
ebml->last_pos = G_MAXUINT64; /* force segment event */
ebml->cache = NULL;
ebml->streamheader = NULL;
ebml->streamheader_pos = 0;
ebml->writing_streamheader = FALSE;
ebml->caps = NULL;
}
static void
gst_ebml_write_finalize (GObject * object)
{
GstEbmlWrite *ebml = GST_EBML_WRITE (object);
gst_object_unref (ebml->srcpad);
if (ebml->cache) {
gst_byte_writer_free (ebml->cache);
ebml->cache = NULL;
}
if (ebml->streamheader) {
gst_byte_writer_free (ebml->streamheader);
ebml->streamheader = NULL;
}
if (ebml->caps) {
gst_caps_unref (ebml->caps);
ebml->caps = NULL;
}
G_OBJECT_CLASS (parent_class)->finalize (object);
}
/**
* gst_ebml_write_new:
* @srcpad: Source pad to which the output will be pushed.
*
* Creates a new #GstEbmlWrite.
*
* Returns: a new #GstEbmlWrite
*/
GstEbmlWrite *
gst_ebml_write_new (GstPad * srcpad)
{
GstEbmlWrite *ebml =
GST_EBML_WRITE (g_object_new (GST_TYPE_EBML_WRITE, NULL));
ebml->srcpad = gst_object_ref (srcpad);
ebml->timestamp = GST_CLOCK_TIME_NONE;
gst_ebml_write_reset (ebml);
return ebml;
}
/**
* gst_ebml_write_reset:
* @ebml: a #GstEbmlWrite.
*
* Reset internal state of #GstEbmlWrite.
*/
void
gst_ebml_write_reset (GstEbmlWrite * ebml)
{
ebml->pos = 0;
ebml->last_pos = G_MAXUINT64; /* force segment event */
if (ebml->cache) {
gst_byte_writer_free (ebml->cache);
ebml->cache = NULL;
}
if (ebml->caps) {
gst_caps_unref (ebml->caps);
ebml->caps = NULL;
}
ebml->last_write_result = GST_FLOW_OK;
ebml->timestamp = GST_CLOCK_TIME_NONE;
}
/**
* gst_ebml_last_write_result:
* @ebml: a #GstEbmlWrite.
*
* Returns: GST_FLOW_OK if there was not write error since the last call of
* gst_ebml_last_write_result or code of the error.
*/
GstFlowReturn
gst_ebml_last_write_result (GstEbmlWrite * ebml)
{
GstFlowReturn res = ebml->last_write_result;
ebml->last_write_result = GST_FLOW_OK;
return res;
}
void
gst_ebml_start_streamheader (GstEbmlWrite * ebml)
{
g_return_if_fail (ebml->streamheader == NULL);
GST_DEBUG ("Starting streamheader at %" G_GUINT64_FORMAT, ebml->pos);
ebml->streamheader = gst_byte_writer_new_with_size (1000, FALSE);
ebml->streamheader_pos = ebml->pos;
ebml->writing_streamheader = TRUE;
}
GstBuffer *
gst_ebml_stop_streamheader (GstEbmlWrite * ebml)
{
GstBuffer *buffer;
if (!ebml->streamheader)
return NULL;
buffer = gst_byte_writer_free_and_get_buffer (ebml->streamheader);
ebml->streamheader = NULL;
GST_DEBUG ("Streamheader was size %" G_GSIZE_FORMAT,
gst_buffer_get_size (buffer));
ebml->writing_streamheader = FALSE;
return buffer;
}
/**
* gst_ebml_write_set_cache:
* @ebml: a #GstEbmlWrite.
* @size: size of the cache.
* Create a cache.
*
* The idea is that you use this for writing a lot
* of small elements. This will just "queue" all of
* them and they'll be pushed to the next element all
* at once. This saves memory and time for buffer
* allocation and init, and it looks better.
*/
void
gst_ebml_write_set_cache (GstEbmlWrite * ebml, guint size)
{
g_return_if_fail (ebml->cache == NULL);
GST_DEBUG ("Starting cache at %" G_GUINT64_FORMAT, ebml->pos);
ebml->cache = gst_byte_writer_new_with_size (size, FALSE);
ebml->cache_pos = ebml->pos;
}
static gboolean
gst_ebml_writer_send_segment_event (GstEbmlWrite * ebml, guint64 new_pos)
{
GstSegment segment;
gboolean res;
GST_INFO ("seeking to %" G_GUINT64_FORMAT, new_pos);
gst_segment_init (&segment,
ebml->streamable ? GST_FORMAT_TIME : GST_FORMAT_BYTES);
segment.start = new_pos;
segment.stop = -1;
segment.position = 0;
res = gst_pad_push_event (ebml->srcpad, gst_event_new_segment (&segment));
if (!res)
GST_WARNING ("seek to %" G_GUINT64_FORMAT "failed", new_pos);
return res;
}
/**
* gst_ebml_write_flush_cache:
* @ebml: a #GstEbmlWrite.
* @timestamp: timestamp of the buffer.
*
* Flush the cache.
*/
void
gst_ebml_write_flush_cache (GstEbmlWrite * ebml, gboolean is_keyframe,
GstClockTime timestamp)
{
GstBuffer *buffer;
if (!ebml->cache)
return;
buffer = gst_byte_writer_free_and_get_buffer (ebml->cache);
ebml->cache = NULL;
GST_DEBUG ("Flushing cache of size %" G_GSIZE_FORMAT,
gst_buffer_get_size (buffer));
GST_BUFFER_TIMESTAMP (buffer) = timestamp;
GST_BUFFER_OFFSET (buffer) = ebml->pos - gst_buffer_get_size (buffer);
GST_BUFFER_OFFSET_END (buffer) = ebml->pos;
if (ebml->last_write_result == GST_FLOW_OK) {
if (GST_BUFFER_OFFSET (buffer) != ebml->last_pos) {
gst_ebml_writer_send_segment_event (ebml, GST_BUFFER_OFFSET (buffer));
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
} else {
GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DISCONT);
}
if (ebml->writing_streamheader) {
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_HEADER);
} else {
GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_HEADER);
}
if (!is_keyframe) {
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DELTA_UNIT);
}
ebml->last_pos = ebml->pos;
ebml->last_write_result = gst_pad_push (ebml->srcpad, buffer);
} else {
gst_buffer_unref (buffer);
}
}
/**
* gst_ebml_write_element_new:
* @ebml: a #GstEbmlWrite.
* @size: size of the requested buffer.
*
* Create a buffer for one element. If there is
* a cache, use that instead.
*
* Returns: A new #GstBuffer.
*/
static GstBuffer *
gst_ebml_write_element_new (GstEbmlWrite * ebml, GstMapInfo * map, guint size)
{
/* Create new buffer of size + ID + length */
GstBuffer *buf;
/* length, ID */
size += 12;
buf = gst_buffer_new_and_alloc (size);
GST_BUFFER_TIMESTAMP (buf) = ebml->timestamp;
/* FIXME unmap not possible */
gst_buffer_map (buf, map, GST_MAP_WRITE);
return buf;
}
/**
* gst_ebml_write_element_id:
* @data_inout: Pointer to data pointer
* @id: Element ID that should be written.
*
* Write element ID into a buffer.
*/
static void
gst_ebml_write_element_id (guint8 ** data_inout, guint32 id)
{
guint8 *data = *data_inout;
guint bytes = 4, mask = 0x10;
/* get ID length */
while (!(id & (mask << ((bytes - 1) * 8))) && bytes > 0) {
mask <<= 1;
bytes--;
}
/* if invalid ID, use dummy */
if (bytes == 0) {
GST_WARNING ("Invalid ID, voiding");
bytes = 1;
id = GST_EBML_ID_VOID;
}
/* write out, BE */
*data_inout += bytes;
while (bytes--) {
data[bytes] = id & 0xff;
id >>= 8;
}
}
/**
* gst_ebml_write_element_size:
* @data_inout: Pointer to data pointer
* @size: Element length.
*
* Write element length into a buffer.
*/
static void
gst_ebml_write_element_size (guint8 ** data_inout, guint64 size)
{
guint8 *data = *data_inout;
guint bytes = 1, mask = 0x80;
if (size != GST_EBML_SIZE_UNKNOWN) {
/* how many bytes? - use mask-1 because an all-1 bitset is not allowed */
while (bytes <= 8 && (size >> ((bytes - 1) * 8)) >= (mask - 1)) {
mask >>= 1;
bytes++;
}
/* if invalid size, use max. */
if (bytes > 8) {
GST_WARNING ("Invalid size, writing size unknown");
mask = 0x01;
bytes = 8;
/* Now here's a real FIXME: we cannot read those yet! */
size = GST_EBML_SIZE_UNKNOWN;
}
} else {
mask = 0x01;
bytes = 8;
}
/* write out, BE, with length size marker */
*data_inout += bytes;
while (bytes-- > 0) {
data[bytes] = size & 0xff;
size >>= 8;
if (!bytes)
*data |= mask;
}
}
/**
* gst_ebml_write_element_data:
* @data_inout: Pointer to data pointer
* @write: Data that should be written.
* @length: Length of the data.
*
* Write element data into a buffer.
*/
static void
gst_ebml_write_element_data (guint8 ** data_inout, guint8 * write,
guint64 length)
{
memcpy (*data_inout, write, length);
*data_inout += length;
}
/**
* gst_ebml_write_element_push:
* @ebml: #GstEbmlWrite
* @buf: #GstBuffer to be written.
* @buf_data: Start of data to push from @buf (or NULL for whole buffer).
* @buf_data_end: Data pointer positioned after the last byte in @buf_data (or
* NULL for whole buffer).
*
* Write out buffer by moving it to the next element.
*/
static void
gst_ebml_write_element_push (GstEbmlWrite * ebml, GstBuffer * buf,
guint8 * buf_data, guint8 * buf_data_end)
{
GstMapInfo map;
guint data_size;
map.data = NULL;
if (buf_data_end)
data_size = buf_data_end - buf_data;
else
data_size = gst_buffer_get_size (buf);
ebml->pos += data_size;
/* if there's no cache, then don't push it! */
if (ebml->writing_streamheader) {
if (!buf_data) {
gst_buffer_map (buf, &map, GST_MAP_READ);
buf_data = map.data;
}
if (!buf_data)
GST_WARNING ("Failed to map buffer");
else if (!gst_byte_writer_put_data (ebml->streamheader, buf_data,
data_size))
GST_WARNING ("Error writing data to streamheader");
}
if (ebml->cache) {
if (!buf_data) {
gst_buffer_map (buf, &map, GST_MAP_READ);
buf_data = map.data;
}
if (!buf_data)
GST_WARNING ("Failed to map buffer");
else if (!gst_byte_writer_put_data (ebml->cache, buf_data, data_size))
GST_WARNING ("Error writing data to cache");
if (map.data)
gst_buffer_unmap (buf, &map);
gst_buffer_unref (buf);
return;
}
if (buf_data && map.data)
gst_buffer_unmap (buf, &map);
if (ebml->last_write_result == GST_FLOW_OK) {
buf = gst_buffer_make_writable (buf);
GST_BUFFER_OFFSET (buf) = ebml->pos - data_size;
GST_BUFFER_OFFSET_END (buf) = ebml->pos;
if (ebml->writing_streamheader) {
GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_HEADER);
} else {
GST_BUFFER_FLAG_UNSET (buf, GST_BUFFER_FLAG_HEADER);
}
GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DELTA_UNIT);
if (GST_BUFFER_OFFSET (buf) != ebml->last_pos) {
gst_ebml_writer_send_segment_event (ebml, GST_BUFFER_OFFSET (buf));
GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
} else {
GST_BUFFER_FLAG_UNSET (buf, GST_BUFFER_FLAG_DISCONT);
}
ebml->last_pos = ebml->pos;
ebml->last_write_result = gst_pad_push (ebml->srcpad, buf);
} else {
gst_buffer_unref (buf);
}
}
/**
* gst_ebml_write_seek:
* @ebml: #GstEbmlWrite
* @pos: Seek position.
*
* Seek.
*/
void
gst_ebml_write_seek (GstEbmlWrite * ebml, guint64 pos)
{
if (ebml->writing_streamheader) {
GST_DEBUG ("wanting to seek to pos %" G_GUINT64_FORMAT, pos);
if (pos >= ebml->streamheader_pos &&
pos <= ebml->streamheader_pos + ebml->streamheader->parent.size) {
gst_byte_writer_set_pos (ebml->streamheader,
pos - ebml->streamheader_pos);
GST_DEBUG ("seeked in streamheader to position %" G_GUINT64_FORMAT,
pos - ebml->streamheader_pos);
} else {
GST_WARNING
("we are writing streamheader still and seek is out of bounds");
}
}
/* Cache seeking. A bit dangerous, we assume the client writer
* knows what he's doing... */
if (ebml->cache) {
/* within bounds? */
if (pos >= ebml->cache_pos &&
pos <= ebml->cache_pos + ebml->cache->parent.size) {
GST_DEBUG ("seeking in cache to %" G_GUINT64_FORMAT, pos);
ebml->pos = pos;
gst_byte_writer_set_pos (ebml->cache, ebml->pos - ebml->cache_pos);
return;
} else {
GST_LOG ("Seek outside cache range. Clearing...");
gst_ebml_write_flush_cache (ebml, FALSE, GST_CLOCK_TIME_NONE);
}
}
GST_INFO ("scheduling seek to %" G_GUINT64_FORMAT, pos);
ebml->pos = pos;
}
/**
* gst_ebml_write_get_uint_size:
* @num: Number to be encoded.
*
* Get number of bytes needed to write a uint.
*
* Returns: Encoded uint length.
*/
static guint
gst_ebml_write_get_uint_size (guint64 num)
{
guint size = 1;
/* get size */
while (size < 8 && num >= (G_GINT64_CONSTANT (1) << (size * 8))) {
size++;
}
return size;
}
/**
* gst_ebml_write_set_uint:
* @data_inout: Pointer to data pointer
* @num: Number to be written.
* @size: Encoded number length.
*
* Write an uint into a buffer.
*/
static void
gst_ebml_write_set_uint (guint8 ** data_inout, guint64 num, guint size)
{
guint8 *data = *data_inout;
*data_inout += size;
while (size-- > 0) {
data[size] = num & 0xff;
num >>= 8;
}
}
/**
* gst_ebml_write_uint:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @num: Number to be written.
*
* Write uint element.
*/
void
gst_ebml_write_uint (GstEbmlWrite * ebml, guint32 id, guint64 num)
{
GstBuffer *buf;
guint8 *data_start, *data_end;
guint size = gst_ebml_write_get_uint_size (num);
GstMapInfo map;
buf = gst_ebml_write_element_new (ebml, &map, sizeof (num));
data_end = data_start = map.data;
/* write */
gst_ebml_write_element_id (&data_end, id);
gst_ebml_write_element_size (&data_end, size);
gst_ebml_write_set_uint (&data_end, num, size);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
}
/**
* gst_ebml_write_sint:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @num: Number to be written.
*
* Write sint element.
*/
void
gst_ebml_write_sint (GstEbmlWrite * ebml, guint32 id, gint64 num)
{
GstBuffer *buf;
guint8 *data_start, *data_end;
GstMapInfo map;
/* if the signed number is on the edge of a extra-byte,
* then we'll fall over when detecting it. Example: if I
* have a number (-)0x8000 (G_MINSHORT), then my abs()<<1
* will be 0x10000; this is G_MAXUSHORT+1! So: if (<0) -1. */
guint64 unum = (num < 0 ? (-num - 1) << 1 : num << 1);
guint size = gst_ebml_write_get_uint_size (unum);
buf = gst_ebml_write_element_new (ebml, &map, sizeof (num));
data_end = data_start = map.data;
/* make unsigned */
if (num >= 0) {
unum = num;
} else {
unum = ((guint64) 0x80) << ((size - 1) * 8);
unum += num;
unum |= ((guint64) 0x80) << ((size - 1) * 8);
}
/* write */
gst_ebml_write_element_id (&data_end, id);
gst_ebml_write_element_size (&data_end, size);
gst_ebml_write_set_uint (&data_end, unum, size);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
}
/**
* gst_ebml_write_float:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @num: Number to be written.
*
* Write float element.
*/
void
gst_ebml_write_float (GstEbmlWrite * ebml, guint32 id, gdouble num)
{
GstBuffer *buf;
GstMapInfo map;
guint8 *data_start, *data_end;
buf = gst_ebml_write_element_new (ebml, &map, sizeof (num));
data_end = data_start = map.data;
gst_ebml_write_element_id (&data_end, id);
gst_ebml_write_element_size (&data_end, 8);
num = GDOUBLE_TO_BE (num);
gst_ebml_write_element_data (&data_end, (guint8 *) & num, 8);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
}
/**
* gst_ebml_write_ascii:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @str: String to be written.
*
* Write string element.
*/
void
gst_ebml_write_ascii (GstEbmlWrite * ebml, guint32 id, const gchar * str)
{
gint len = strlen (str) + 1; /* add trailing '\0' */
GstBuffer *buf;
GstMapInfo map;
guint8 *data_start, *data_end;
buf = gst_ebml_write_element_new (ebml, &map, len);
data_end = data_start = map.data;
gst_ebml_write_element_id (&data_end, id);
gst_ebml_write_element_size (&data_end, len);
gst_ebml_write_element_data (&data_end, (guint8 *) str, len);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
}
/**
* gst_ebml_write_utf8:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @str: String to be written.
*
* Write utf8 encoded string element.
*/
void
gst_ebml_write_utf8 (GstEbmlWrite * ebml, guint32 id, const gchar * str)
{
gst_ebml_write_ascii (ebml, id, str);
}
/**
* gst_ebml_write_date:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @date: Date in nanoseconds since the unix epoch.
*
* Write date element.
*/
void
gst_ebml_write_date (GstEbmlWrite * ebml, guint32 id, gint64 date)
{
gst_ebml_write_sint (ebml, id, date - GST_EBML_DATE_OFFSET);
}
/**
* gst_ebml_write_master_start:
* @ebml: #GstEbmlWrite
* @id: Element ID.
*
* Start wiriting mater element.
*
* Master writing is annoying. We use a size marker of
* the max. allowed length, so that we can later fill it
* in validly.
*
* Returns: Master starting position.
*/
guint64
gst_ebml_write_master_start (GstEbmlWrite * ebml, guint32 id)
{
guint64 pos = ebml->pos;
GstBuffer *buf;
GstMapInfo map;
guint8 *data_start, *data_end;
buf = gst_ebml_write_element_new (ebml, &map, 0);
data_end = data_start = map.data;
gst_ebml_write_element_id (&data_end, id);
pos += data_end - data_start;
gst_ebml_write_element_size (&data_end, GST_EBML_SIZE_UNKNOWN);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
return pos;
}
/**
* gst_ebml_write_master_finish_full:
* @ebml: #GstEbmlWrite
* @startpos: Master starting position.
*
* Finish writing master element. Size of master element is difference between
* current position and the element start, and @extra_size added to this.
*/
void
gst_ebml_write_master_finish_full (GstEbmlWrite * ebml, guint64 startpos,
guint64 extra_size)
{
guint64 pos = ebml->pos;
guint8 *data = g_malloc (8);
GstBuffer *buf = gst_buffer_new_wrapped (data, 8);
gst_ebml_write_seek (ebml, startpos);
GST_WRITE_UINT64_BE (data,
(G_GINT64_CONSTANT (1) << 56) | (pos - startpos - 8 + extra_size));
gst_ebml_write_element_push (ebml, buf, NULL, NULL);
gst_ebml_write_seek (ebml, pos);
}
void
gst_ebml_write_master_finish (GstEbmlWrite * ebml, guint64 startpos)
{
gst_ebml_write_master_finish_full (ebml, startpos, 0);
}
/**
* gst_ebml_write_binary:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @binary: Data to be written.
* @length: Length of the data
*
* Write an element with binary data.
*/
void
gst_ebml_write_binary (GstEbmlWrite * ebml,
guint32 id, guint8 * binary, guint64 length)
{
GstBuffer *buf;
GstMapInfo map;
guint8 *data_start, *data_end;
buf = gst_ebml_write_element_new (ebml, &map, length);
data_end = data_start = map.data;
gst_ebml_write_element_id (&data_end, id);
gst_ebml_write_element_size (&data_end, length);
gst_ebml_write_element_data (&data_end, binary, length);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
}
/**
* gst_ebml_write_buffer_header:
* @ebml: #GstEbmlWrite
* @id: Element ID.
* @length: Length of the data
*
* Write header of the binary element (use with gst_ebml_write_buffer function).
*
* For things like video frames and audio samples,
* you want to use this function, as it doesn't have
* the overhead of memcpy() that other functions
* such as write_binary() do have.
*/
void
gst_ebml_write_buffer_header (GstEbmlWrite * ebml, guint32 id, guint64 length)
{
GstBuffer *buf;
GstMapInfo map;
guint8 *data_start, *data_end;
buf = gst_ebml_write_element_new (ebml, &map, 0);
data_end = data_start = map.data;
gst_ebml_write_element_id (&data_end, id);
gst_ebml_write_element_size (&data_end, length);
gst_buffer_unmap (buf, &map);
gst_buffer_set_size (buf, (data_end - data_start));
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
}
/**
* gst_ebml_write_buffer:
* @ebml: #GstEbmlWrite
* @buf: #GstBuffer containing the data.
*
* Write binary element (see gst_ebml_write_buffer_header).
*/
void
gst_ebml_write_buffer (GstEbmlWrite * ebml, GstBuffer * buf)
{
gst_ebml_write_element_push (ebml, buf, NULL, NULL);
}
/**
* gst_ebml_replace_uint:
* @ebml: #GstEbmlWrite
* @pos: Position of the uint that should be replaced.
* @num: New value.
*
* Replace uint with a new value.
*
* When replacing a uint, we assume that it is *always*
* 8-byte, since that's the safest guess we can do. This
* is just for simplicity.
*
* FIXME: this function needs to be replaced with something
* proper. This is a crude hack.
*/
void
gst_ebml_replace_uint (GstEbmlWrite * ebml, guint64 pos, guint64 num)
{
guint64 oldpos = ebml->pos;
guint8 *data_start, *data_end;
GstBuffer *buf;
data_start = g_malloc (8);
data_end = data_start;
buf = gst_buffer_new_wrapped (data_start, 8);
gst_ebml_write_seek (ebml, pos);
gst_ebml_write_set_uint (&data_end, num, 8);
gst_ebml_write_element_push (ebml, buf, data_start, data_end);
gst_ebml_write_seek (ebml, oldpos);
}
/**
* gst_ebml_write_header:
* @ebml: #GstEbmlWrite
* @doctype: Document type.
* @version: Document type version.
*
* Write EBML header.
*/
void
gst_ebml_write_header (GstEbmlWrite * ebml, const gchar * doctype,
guint version)
{
guint64 pos;
/* write the basic EBML header */
gst_ebml_write_set_cache (ebml, 0x40);
pos = gst_ebml_write_master_start (ebml, GST_EBML_ID_HEADER);
#if (GST_EBML_VERSION != 1)
gst_ebml_write_uint (ebml, GST_EBML_ID_EBMLVERSION, GST_EBML_VERSION);
gst_ebml_write_uint (ebml, GST_EBML_ID_EBMLREADVERSION, GST_EBML_VERSION);
#endif
#if 0
/* we don't write these until they're "non-default" (never!) */
gst_ebml_write_uint (ebml, GST_EBML_ID_EBMLMAXIDLENGTH, sizeof (guint32));
gst_ebml_write_uint (ebml, GST_EBML_ID_EBMLMAXSIZELENGTH, sizeof (guint64));
#endif
gst_ebml_write_ascii (ebml, GST_EBML_ID_DOCTYPE, doctype);
gst_ebml_write_uint (ebml, GST_EBML_ID_DOCTYPEVERSION, version);
gst_ebml_write_uint (ebml, GST_EBML_ID_DOCTYPEREADVERSION, version);
gst_ebml_write_master_finish (ebml, pos);
gst_ebml_write_flush_cache (ebml, FALSE, 0);
}