gstreamer/gst/mxf/mxfalaw.c
2009-03-21 10:19:47 +01:00

319 lines
8.6 KiB
C

/* GStreamer
* Copyright (C) 2008-2009 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"
#include "mxfwrite.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,
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
};
typedef struct
{
guint64 error;
gint rate, channels;
MXFFraction edit_rate;
} ALawMappingData;
static GstFlowReturn
mxf_alaw_write_func (GstBuffer * buffer, GstCaps * caps, gpointer mapping_data,
GstAdapter * adapter, GstBuffer ** outbuf, gboolean flush)
{
ALawMappingData *md = mapping_data;
guint bytes;
if (buffer) {
guint64 speu =
gst_util_uint64_scale (md->rate, md->edit_rate.d, md->edit_rate.n);
md->error += (GST_SECOND * md->edit_rate.d * md->rate) % (md->edit_rate.n);
if (md->error >= md->edit_rate.n) {
md->error = 0;
speu += 1;
}
bytes = speu * md->channels;
gst_adapter_push (adapter, buffer);
if (gst_adapter_available (adapter) >= bytes) {
*outbuf = gst_adapter_take_buffer (adapter, bytes);
}
} else if (flush && (bytes = gst_adapter_available (adapter))) {
*outbuf = gst_adapter_take_buffer (adapter, bytes);
}
return GST_FLOW_OK;
}
static const guint8 alaw_essence_container_ul[] = {
0x06, 0x0e, 0x2b, 0x34, 0x04, 0x01, 0x01, 0x03,
0x0d, 0x01, 0x03, 0x01, 0x02, 0x0a, 0x01, 0x00
};
static const MXFUL mxf_sound_essence_compression_alaw =
{ {0x06, 0x0E, 0x2B, 0x34, 0x04, 0x01, 0x01, 0x03, 0x04, 0x02, 0x02, 0x02,
0x03, 0x01, 0x01, 0x00}
};
static MXFMetadataFileDescriptor *
mxf_alaw_get_descriptor (GstPadTemplate * tmpl, GstCaps * caps,
MXFEssenceElementWriteFunc * handler, gpointer * mapping_data)
{
MXFMetadataGenericSoundEssenceDescriptor *ret;
GstStructure *s;
ALawMappingData *md;
gint rate, channels;
s = gst_caps_get_structure (caps, 0);
if (strcmp (gst_structure_get_name (s), "audio/x-alaw") != 0)
return NULL;
if (!gst_structure_get_int (s, "rate", &rate) ||
!gst_structure_get_int (s, "channels", &channels))
return NULL;
ret = (MXFMetadataGenericSoundEssenceDescriptor *)
gst_mini_object_new (MXF_TYPE_METADATA_GENERIC_SOUND_ESSENCE_DESCRIPTOR);
memcpy (&ret->parent.essence_container, &alaw_essence_container_ul, 16);
memcpy (&ret->sound_essence_compression, &mxf_sound_essence_compression_alaw,
16);
mxf_metadata_generic_sound_essence_descriptor_from_caps (ret, caps);
*handler = mxf_alaw_write_func;
md = g_new0 (ALawMappingData, 1);
md->rate = rate;
md->channels = channels;
*mapping_data = md;
return (MXFMetadataFileDescriptor *) ret;
}
static void
mxf_alaw_update_descriptor (MXFMetadataFileDescriptor * d, GstCaps * caps,
gpointer mapping_data, GstBuffer * buf)
{
return;
}
static guint
gst_greatest_common_divisor (guint a, guint b)
{
while (b != 0) {
guint temp = a;
a = b;
b = temp % b;
}
return a;
}
static void
mxf_alaw_get_edit_rate (MXFMetadataFileDescriptor * a, GstCaps * caps,
gpointer mapping_data, GstBuffer * buf, MXFMetadataSourcePackage * package,
MXFMetadataTimelineTrack * track, MXFFraction * edit_rate)
{
guint i;
gdouble min = G_MAXDOUBLE;
MXFMetadataGenericSoundEssenceDescriptor *d =
MXF_METADATA_GENERIC_SOUND_ESSENCE_DESCRIPTOR (a);
ALawMappingData *md = mapping_data;
for (i = 0; i < package->parent.n_tracks; i++) {
MXFMetadataTimelineTrack *tmp;
if (!MXF_IS_METADATA_TIMELINE_TRACK (package->parent.tracks[i]) ||
package->parent.tracks[i] == (MXFMetadataTrack *) track)
continue;
tmp = MXF_METADATA_TIMELINE_TRACK (package->parent.tracks[i]);
if (((gdouble) tmp->edit_rate.n) / ((gdouble) tmp->edit_rate.d) < min) {
min = ((gdouble) tmp->edit_rate.n) / ((gdouble) tmp->edit_rate.d);
memcpy (edit_rate, &tmp->edit_rate, sizeof (MXFFraction));
}
}
if (min == G_MAXDOUBLE) {
guint32 nu, de;
guint gcd;
/* 50ms edit units */
nu = d->audio_sampling_rate.n;
de = d->audio_sampling_rate.d * 20;
gcd = gst_greatest_common_divisor (nu, de);
nu /= gcd;
de /= gcd;
(*edit_rate).n = nu;
(*edit_rate).d = de;
}
memcpy (&md->edit_rate, edit_rate, sizeof (MXFFraction));
}
static guint32
mxf_alaw_get_track_number_template (MXFMetadataFileDescriptor * a,
GstCaps * caps, gpointer mapping_data)
{
return (0x16 << 24) | (0x08 << 8);
}
static MXFEssenceElementWriter mxf_alaw_essence_element_writer = {
mxf_alaw_get_descriptor,
mxf_alaw_update_descriptor,
mxf_alaw_get_edit_rate,
mxf_alaw_get_track_number_template,
NULL,
{{0,}}
};
#define ALAW_CAPS \
"audio/x-alaw, " \
"rate = (int) [ 8000, 192000 ], " \
"channels = (int) [ 1, 2 ]"
void
mxf_alaw_init (void)
{
mxf_essence_element_handler_register (&mxf_alaw_essence_element_handler);
mxf_alaw_essence_element_writer.pad_template =
gst_pad_template_new ("alaw_audio_sink_%u", GST_PAD_SINK, GST_PAD_REQUEST,
gst_caps_from_string (ALAW_CAPS));
memcpy (&mxf_alaw_essence_element_writer.data_definition,
mxf_metadata_track_identifier_get (MXF_METADATA_TRACK_SOUND_ESSENCE), 16);
mxf_essence_element_writer_register (&mxf_alaw_essence_element_writer);
}