gstreamer/gst/iec958/ac3iec.c

/* GStreamer
 * Copyright (C) 2004 Martin Soto <martinsoto@users.sourceforge.net>
                 2005 Michael Smith <msmith@fluendo.com>
 *
 * ac3iec.c: Pad AC3 frames into IEC958 frames for the S/PDIF interface.
 *
 * 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/gst.h>

#include "ac3iec.h"


GST_DEBUG_CATEGORY_STATIC (ac3iec_debug);
#define GST_CAT_DEFAULT (ac3iec_debug)


/* The duration of a single IEC958 frame. */
#define IEC958_FRAME_DURATION (32 * GST_MSECOND)


/* ElementFactory information. */
static GstElementDetails ac3iec_details = {
  "AC3 to IEC958 filter",
  "audio/x-private1-ac3",
  "Pads AC3 frames into IEC958 frames suitable for a raw S/PDIF interface",
  "Martin Soto <martinsoto@users.sourceforge.net>"
};


/* AC3IEC signals and args */
enum
{
  LAST_SIGNAL,
};

enum
{
  ARG_0,
};


static GstStaticPadTemplate ac3iec_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-private1-ac3")
    );

static GstStaticPadTemplate ac3iec_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("audio/x-iec958")
    );

static void ac3iec_base_init (gpointer g_class);
static void ac3iec_class_init (AC3IECClass * klass);
static void ac3iec_init (AC3IEC * ac3iec);
static void ac3iec_finalize (GObject * object);

static void ac3iec_set_property (GObject * object,
    guint prop_id, const GValue * value, GParamSpec * pspec);
static void ac3iec_get_property (GObject * object,
    guint prop_id, GValue * value, GParamSpec * pspec);

static GstFlowReturn ac3iec_chain_dvd (GstPad * pad, GstBuffer * buf);
static GstFlowReturn ac3iec_chain_raw (GstPad * pad, GstBuffer * buf);

static GstStateChangeReturn ac3iec_change_state (GstElement * element,
    GstStateChange transition);


static GstElementClass *parent_class = NULL;

/* static guint ac3iec_signals[LAST_SIGNAL] = { 0 }; */


GType
ac3iec_get_type (void)
{
  static GType ac3iec_type = 0;

  if (!ac3iec_type) {
    static const GTypeInfo ac3iec_info = {
      sizeof (AC3IECClass),
      ac3iec_base_init,
      NULL,
      (GClassInitFunc) ac3iec_class_init,
      NULL,
      NULL,
      sizeof (AC3IEC),
      0,
      (GInstanceInitFunc) ac3iec_init,
    };
    ac3iec_type = g_type_register_static (GST_TYPE_ELEMENT,
        "AC3IEC", &ac3iec_info, 0);

    GST_DEBUG_CATEGORY_INIT (ac3iec_debug, "ac3iec", 0,
        "AC3 to IEC958 padding element");
  }
  return ac3iec_type;
}

static void
ac3iec_base_init (gpointer g_class)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_set_details (element_class, &ac3iec_details);
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&ac3iec_sink_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&ac3iec_src_template));
}


static void
ac3iec_class_init (AC3IECClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);

  gobject_class->set_property = ac3iec_set_property;
  gobject_class->get_property = ac3iec_get_property;
  gobject_class->finalize = ac3iec_finalize;

  gstelement_class->change_state = ac3iec_change_state;
}


static void
ac3iec_init (AC3IEC * ac3iec)
{
  ac3iec->sink =
      gst_pad_new_from_template (gst_static_pad_template_get
      (&ac3iec_sink_template), "sink");
  gst_pad_set_chain_function (ac3iec->sink, ac3iec_chain_dvd);
  gst_element_add_pad (GST_ELEMENT (ac3iec), ac3iec->sink);

  ac3iec->src =
      gst_pad_new_from_template (gst_static_pad_template_get
      (&ac3iec_src_template), "src");
  gst_pad_use_fixed_caps (ac3iec->src);
  gst_element_add_pad (GST_ELEMENT (ac3iec), ac3iec->src);


  ac3iec->cur_ts = GST_CLOCK_TIME_NONE;

  ac3iec->padder = g_malloc (sizeof (ac3_padder));
}


static void
ac3iec_finalize (GObject * object)
{
  AC3IEC *ac3iec = AC3IEC (object);

  g_free (ac3iec->padder);
}

static void
ac3iec_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  AC3IEC *ac3iec;

  /* it's not null if we got it, but it might not be ours */
  ac3iec = AC3IEC (object);

  switch (prop_id) {
    default:
      break;
  }
}


static void
ac3iec_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  AC3IEC *ac3iec;

  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_AC3IEC (object));

  ac3iec = AC3IEC (object);

  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstFlowReturn
ac3iec_chain_dvd (GstPad * pad, GstBuffer * buf)
{
  guint first_access;
  guint8 *data;
  guint size;
  gint offset;
  gint len;
  GstBuffer *subbuf;
  GstFlowReturn ret;

  size = GST_BUFFER_SIZE (buf);
  data = GST_BUFFER_DATA (buf);

  first_access = (data[0] << 8) | data[1];

  /* Skip the first_access header */
  offset = 2;

  if (first_access > 1) {
    /* Length of data before first_access */
    len = first_access - 1;

    /* Ensure we don't crash if fed totally invalid data */
    if (offset + len > size) {
      ret = GST_FLOW_ERROR;
      goto done;
    }

    if (len > 0) {
      subbuf = gst_buffer_create_sub (buf, offset, len);
      GST_BUFFER_TIMESTAMP (subbuf) = GST_CLOCK_TIME_NONE;
      ret = ac3iec_chain_raw (pad, subbuf);
      if (ret != GST_FLOW_OK)
        goto done;
    }

    offset += len;
    len = size - offset;

    subbuf = gst_buffer_create_sub (buf, offset, len);
    GST_BUFFER_TIMESTAMP (subbuf) = GST_BUFFER_TIMESTAMP (buf);

    ret = ac3iec_chain_raw (pad, subbuf);
  } else {
    /* Ensure we don't crash if fed totally invalid data */
    if (size < 2) {
      ret = GST_FLOW_ERROR;
      goto done;
    }

    /* No first_access, so no timestamp */
    subbuf = gst_buffer_create_sub (buf, offset, size - offset);
    GST_BUFFER_TIMESTAMP (subbuf) = GST_CLOCK_TIME_NONE;
    ret = ac3iec_chain_raw (pad, subbuf);
  }

done:
  gst_buffer_unref (buf);

  return ret;
}

static GstFlowReturn
ac3iec_chain_raw (GstPad * pad, GstBuffer * buf)
{
  GstBuffer *new;
  AC3IEC *ac3iec;
  int event;
  GstFlowReturn ret = GST_FLOW_OK;

  g_return_val_if_fail (pad != NULL, GST_FLOW_ERROR);
  g_return_val_if_fail (GST_IS_PAD (pad), GST_FLOW_ERROR);
  g_return_val_if_fail (buf != NULL, GST_FLOW_ERROR);

  ac3iec = AC3IEC (gst_pad_get_parent (pad));

  if (GST_BUFFER_TIMESTAMP (buf) != GST_CLOCK_TIME_NONE) {
    /* Whoever tells me why it is necessary to add a frame in order to
       get synchronized sound will get a beer from me. */
    ac3iec->cur_ts = GST_BUFFER_TIMESTAMP (buf) + IEC958_FRAME_DURATION;
  }

  /* Push the new data into the padder. */
  ac3p_push_data (ac3iec->padder, GST_BUFFER_DATA (buf), GST_BUFFER_SIZE (buf));

  /* Parse the data. */
  event = ac3p_parse (ac3iec->padder);
  while (event != AC3P_EVENT_PUSH) {
    if (event == AC3P_EVENT_FRAME) {
      /* We have a new frame: */
      GstCaps *bufcaps = GST_PAD_CAPS (ac3iec->src);

      /* Create a new buffer, and copy the frame data into it. */
      ret = gst_pad_alloc_buffer (ac3iec->src, 0, AC3P_IEC_FRAME_SIZE,
          bufcaps, &new);
      if (ret != GST_FLOW_OK)
        goto buffer_alloc_failed;

      memcpy (GST_BUFFER_DATA (new), ac3p_frame (ac3iec->padder),
          AC3P_IEC_FRAME_SIZE);

      /* Set the timestamp. */
      GST_BUFFER_TIMESTAMP (new) = ac3iec->cur_ts;
      GST_BUFFER_DURATION (new) = IEC958_FRAME_DURATION;
      ac3iec->cur_ts = GST_CLOCK_TIME_NONE;

      GST_LOG_OBJECT (ac3iec, "Pushing IEC958 buffer of size %d",
          GST_BUFFER_SIZE (new));
      /* Push the buffer to the source pad. */
      ret = gst_pad_push (ac3iec->src, new);
    }

    event = ac3p_parse (ac3iec->padder);
  }

  gst_buffer_unref (buf);

done:
  gst_object_unref (ac3iec);

  return ret;

buffer_alloc_failed:
  gst_buffer_unref (buf);
  goto done;

}


static GstStateChangeReturn
ac3iec_change_state (GstElement * element, GstStateChange transition)
{
  AC3IEC *ac3iec;

  g_return_val_if_fail (GST_IS_AC3IEC (element), GST_STATE_CHANGE_FAILURE);

  ac3iec = AC3IEC (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      ac3p_init (ac3iec->padder);
      break;
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
      break;
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      ac3p_clear (ac3iec->padder);
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      break;
  }

  if (GST_ELEMENT_CLASS (parent_class)->change_state) {
    return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
  }

  return GST_STATE_CHANGE_SUCCESS;
}


static gboolean
plugin_init (GstPlugin * plugin)
{
  if (!gst_element_register (plugin, "ac3iec958", GST_RANK_NONE,
          GST_TYPE_AC3IEC)) {
    return FALSE;
  }

  return TRUE;
}


GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "iec958",
    "Convert raw AC3 into IEC958 (S/PDIF) frames",
    plugin_init, VERSION, "LGPL", GST_PACKAGE, GST_ORIGIN);