gstreamer/gst/mxf/mxfalaw.c
2009-01-22 13:12:59 +01:00

146 lines
3.8 KiB
C

/* GStreamer
* Copyright (C) 2008 Sebastian Dröge <sebastian.droege@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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* Implementation of SMPTE 388M - Mapping A-Law coded audio into the MXF
* Generic Container
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#include <string.h>
#include "mxfalaw.h"
GST_DEBUG_CATEGORY_EXTERN (mxf_debug);
#define GST_CAT_DEFAULT mxf_debug
static gboolean
mxf_is_alaw_essence_track (const MXFMetadataTimelineTrack * track)
{
guint i;
g_return_val_if_fail (track != NULL, FALSE);
if (track->parent.descriptor == NULL)
return FALSE;
for (i = 0; i < track->parent.n_descriptor; i++) {
MXFMetadataFileDescriptor *d = track->parent.descriptor[i];
MXFUL *key;
if (!d)
continue;
key = &d->essence_container;
/* SMPTE 388M 6.1 */
if (mxf_is_generic_container_essence_container_label (key) &&
key->u[12] == 0x02 && key->u[13] == 0x0a &&
(key->u[14] == 0x01 || key->u[14] == 0x02 || key->u[14] == 0x03))
return TRUE;
}
return FALSE;
}
static GstFlowReturn
mxf_alaw_handle_essence_element (const MXFUL * key, GstBuffer * buffer,
GstCaps * caps,
MXFMetadataTimelineTrack * track,
MXFMetadataSourceClip * component, gpointer mapping_data,
GstBuffer ** outbuf)
{
*outbuf = buffer;
/* SMPTE 388M 5.1 */
if (key->u[12] != 0x16 || (key->u[14] != 0x08 && key->u[14] != 0x09
&& key->u[14] != 0x0a)) {
GST_ERROR ("Invalid A-Law essence element");
return GST_FLOW_ERROR;
}
return GST_FLOW_OK;
}
static GstCaps *
mxf_alaw_create_caps (MXFMetadataTimelineTrack * track, GstTagList ** tags,
MXFEssenceElementHandleFunc * handler, gpointer * mapping_data)
{
MXFMetadataGenericSoundEssenceDescriptor *s = NULL;
guint i;
GstCaps *caps = NULL;
g_return_val_if_fail (track != NULL, NULL);
if (track->parent.descriptor == NULL) {
GST_ERROR ("No descriptor found for this track");
return NULL;
}
for (i = 0; i < track->parent.n_descriptor; i++) {
if (!track->parent.descriptor[i])
continue;
if (MXF_IS_METADATA_GENERIC_SOUND_ESSENCE_DESCRIPTOR (track->
parent.descriptor[i])) {
s = (MXFMetadataGenericSoundEssenceDescriptor *) track->
parent.descriptor[i];
break;
}
}
if (!s) {
GST_ERROR ("No generic sound essence descriptor found for this track");
return NULL;
}
*handler = mxf_alaw_handle_essence_element;
if (s && s->audio_sampling_rate.n != 0 && s->audio_sampling_rate.d != 0 &&
s->channel_count != 0) {
caps = gst_caps_new_simple ("audio/x-alaw", NULL);
mxf_metadata_generic_sound_essence_descriptor_set_caps (s, caps);
/* TODO: Handle channel layout somehow?
* Or is alaw limited to two channels? */
if (!*tags)
*tags = gst_tag_list_new ();
gst_tag_list_add (*tags, GST_TAG_MERGE_APPEND, GST_TAG_AUDIO_CODEC,
"A-law encoded audio", NULL);
}
return caps;
}
static const MXFEssenceElementHandler mxf_alaw_essence_element_handler = {
mxf_is_alaw_essence_track,
mxf_alaw_create_caps
};
void
mxf_alaw_init (void)
{
mxf_essence_element_handler_register (&mxf_alaw_essence_element_handler);
}