gstreamer/subprojects/gst-plugins-base/ext/opus/gstopusheader.c

93 lines
2.5 KiB
C

/* GStreamer Opus Encoder
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) <2008> Sebastian Dröge <sebastian.droege@collabora.co.uk>
* Copyright (C) <2011> Vincent Penquerc'h <vincent.penquerch@collabora.co.uk>
*
* 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 <gst/tag/tag.h>
#include <gst/base/gstbytewriter.h>
#include "gstopusheader.h"
gboolean
gst_opus_header_is_header (GstBuffer * buf, const char *magic, guint magic_size)
{
return (gst_buffer_get_size (buf) >= magic_size
&& !gst_buffer_memcmp (buf, 0, magic, magic_size));
}
gboolean
gst_opus_header_is_id_header (GstBuffer * buf)
{
gsize size = gst_buffer_get_size (buf);
guint8 *data = NULL;
guint8 version, channels, channel_mapping_family, n_streams, n_stereo_streams;
gboolean ret = FALSE;
GstMapInfo map;
if (size < 19)
goto beach;
if (!gst_opus_header_is_header (buf, "OpusHead", 8))
goto beach;
gst_buffer_map (buf, &map, GST_MAP_READ);
data = map.data;
size = map.size;
version = data[8];
if (version >= 0x0f) /* major version >=0 is what we grok */
goto beach;
channels = data[9];
if (channels == 0)
goto beach;
channel_mapping_family = data[18];
if (channel_mapping_family == 0) {
if (channels > 2)
goto beach;
} else {
channels = data[9];
if (size < 21 + channels)
goto beach;
n_streams = data[19];
n_stereo_streams = data[20];
if (n_streams == 0)
goto beach;
if (n_stereo_streams > n_streams)
goto beach;
if (n_streams + n_stereo_streams > 255)
goto beach;
}
ret = TRUE;
beach:
if (data)
gst_buffer_unmap (buf, &map);
return ret;
}
gboolean
gst_opus_header_is_comment_header (GstBuffer * buf)
{
return gst_opus_header_is_header (buf, "OpusTags", 8);
}