gstbasesrc.c

gnash 在pc和嵌入式下开发需要的源码

  gst_pad_set_fixatecaps_function (pad,
      GST_DEBUG_FUNCPTR (gst_base_src_fixate));

  /* hold pointer to pad */
  basesrc->srcpad = pad;
  GST_DEBUG_OBJECT (basesrc, "adding src pad");
  gst_element_add_pad (GST_ELEMENT (basesrc), pad);

  basesrc->blocksize = DEFAULT_BLOCKSIZE;
  basesrc->clock_id = NULL;
  /* we operate in BYTES by default */
  gst_base_src_set_format (basesrc, GST_FORMAT_BYTES);
  basesrc->data.ABI.typefind = DEFAULT_TYPEFIND;
  basesrc->priv->do_timestamp = DEFAULT_DO_TIMESTAMP;

  GST_OBJECT_FLAG_UNSET (basesrc, GST_BASE_SRC_STARTED);

  GST_DEBUG_OBJECT (basesrc, "init done");
}

static void
gst_base_src_finalize (GObject * object)
{
  GstBaseSrc *basesrc;
  GstEvent **event_p;

  basesrc = GST_BASE_SRC (object);

  g_mutex_free (basesrc->live_lock);
  g_cond_free (basesrc->live_cond);

  event_p = &basesrc->data.ABI.pending_seek;
  gst_event_replace (event_p, NULL);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

/**
 * gst_base_src_wait_playing:
 * @src: the src
 *
 * If the #GstBaseSrcClass::create method performs its own synchronisation against
 * the clock it must unblock when going from PLAYING to the PAUSED state and call
 * this method before continuing to produce the remaining data.
 *
 * This function will block until a state change to PLAYING happens (in which
 * case this function returns #GST_FLOW_OK) or the processing must be stopped due
 * to a state change to READY or a FLUSH event (in which case this function
 * returns #GST_FLOW_WRONG_STATE).
 *
 * Since: 0.10.12
 *
 * Returns: #GST_FLOW_OK if @src is PLAYING and processing can
 * continue. Any other return value should be returned from the create vmethod.
 */
GstFlowReturn
gst_base_src_wait_playing (GstBaseSrc * src)
{
  /* block until the state changes, or we get a flush, or something */
  if (src->is_live) {
    while (G_UNLIKELY (!src->live_running)) {
      GST_DEBUG ("live source signal waiting");
      GST_LIVE_SIGNAL (src);
      GST_DEBUG ("live source waiting for running state");
      GST_LIVE_WAIT (src);
      GST_DEBUG ("live source unlocked");
    }
    if (src->priv->flushing)
      goto flushing;
  }

  return GST_FLOW_OK;

  /* ERRORS */
flushing:
  {
    GST_DEBUG_OBJECT (src, "we are flushing");
    return GST_FLOW_WRONG_STATE;
  }
}

/**
 * gst_base_src_set_live:
 * @src: base source instance
 * @live: new live-mode
 *
 * If the element listens to a live source, @live should
 * be set to %TRUE. 
 *
 * A live source will not produce data in the PAUSED state and
 * will therefore not be able to participate in the PREROLL phase
 * of a pipeline. To signal this fact to the application and the 
 * pipeline, the state change return value of the live source will
 * be GST_STATE_CHANGE_NO_PREROLL.
 */
void
gst_base_src_set_live (GstBaseSrc * src, gboolean live)
{
  GST_OBJECT_LOCK (src);
  src->is_live = live;
  GST_OBJECT_UNLOCK (src);
}

/**
 * gst_base_src_is_live:
 * @src: base source instance
 *
 * Check if an element is in live mode.
 *
 * Returns: %TRUE if element is in live mode.
 */
gboolean
gst_base_src_is_live (GstBaseSrc * src)
{
  gboolean result;

  GST_OBJECT_LOCK (src);
  result = src->is_live;
  GST_OBJECT_UNLOCK (src);

  return result;
}

/**
 * gst_base_src_set_format:
 * @src: base source instance
 * @format: the format to use
 *
 * Sets the default format of the source. This will be the format used
 * for sending NEW_SEGMENT events and for performing seeks.
 *
 * If a format of GST_FORMAT_BYTES is set, the element will be able to
 * operate in pull mode if the #GstBaseSrc::is_seekable returns TRUE.
 *
 * Since: 0.10.1
 */
void
gst_base_src_set_format (GstBaseSrc * src, GstFormat format)
{
  gst_segment_init (&src->segment, format);
}

/**
 * gst_base_src_query_latency:
 * @src: the source
 * @live: if the source is live
 * @min_latency: the min latency of the source
 * @max_latency: the max latency of the source
 *
 * Query the source for the latency parameters. @live will be TRUE when @src is
 * configured as a live source. @min_latency will be set to the difference
 * between the running time and the timestamp of the first buffer.
 * @max_latency is always the undefined value of -1.
 *
 * This function is mostly used by subclasses. 
 *
 * Returns: TRUE if the query succeeded.
 *
 * Since: 0.10.13
 */
gboolean
gst_base_src_query_latency (GstBaseSrc * src, gboolean * live,
    GstClockTime * min_latency, GstClockTime * max_latency)
{
  GstClockTime min;

  GST_OBJECT_LOCK (src);
  if (live)
    *live = src->is_live;

  /* if we have a startup latency, report this one, else report 0. Subclasses
   * are supposed to override the query function if they want something
   * else. */
  if (src->priv->latency != -1)
    min = src->priv->latency;
  else
    min = 0;

  if (min_latency)
    *min_latency = min;
  if (max_latency)
    *max_latency = -1;

  GST_LOG_OBJECT (src, "latency: live %d, min %" GST_TIME_FORMAT
      ", max %" GST_TIME_FORMAT, src->is_live, GST_TIME_ARGS (min),
      GST_TIME_ARGS (-1));
  GST_OBJECT_UNLOCK (src);

  return TRUE;
}

/**
 * gst_base_src_set_do_timestamp:
 * @src: the source
 * @timestamp: enable or disable timestamping
 *
 * Configure @src to automatically timestamp outgoing buffers based on the
 * current running_time of the pipeline. This property is mostly useful for live
 * sources.
 *
 * Since: 0.10.15
 */
void
gst_base_src_set_do_timestamp (GstBaseSrc * src, gboolean timestamp)
{
  GST_OBJECT_LOCK (src);
  src->priv->do_timestamp = timestamp;
  GST_OBJECT_UNLOCK (src);
}

/**
 * gst_base_src_get_do_timestamp:
 * @src: the source
 *
 * Query if @src timestamps outgoing buffers based on the current running_time.
 *
 * Returns: %TRUE if the base class will automatically timestamp outgoing buffers.
 *
 * Since: 0.10.15
 */
gboolean
gst_base_src_get_do_timestamp (GstBaseSrc * src)
{
  gboolean res;

  GST_OBJECT_LOCK (src);
  res = src->priv->do_timestamp;
  GST_OBJECT_UNLOCK (src);

  return res;
}

static gboolean
gst_base_src_setcaps (GstPad * pad, GstCaps * caps)
{
  GstBaseSrcClass *bclass;
  GstBaseSrc *bsrc;
  gboolean res = TRUE;

  bsrc = GST_BASE_SRC (GST_PAD_PARENT (pad));
  bclass = GST_BASE_SRC_GET_CLASS (bsrc);

  if (bclass->set_caps)
    res = bclass->set_caps (bsrc, caps);

  return res;
}

static GstCaps *
gst_base_src_getcaps (GstPad * pad)
{
  GstBaseSrcClass *bclass;
  GstBaseSrc *bsrc;
  GstCaps *caps = NULL;

  bsrc = GST_BASE_SRC (GST_PAD_PARENT (pad));
  bclass = GST_BASE_SRC_GET_CLASS (bsrc);
  if (bclass->get_caps)
    caps = bclass->get_caps (bsrc);

  if (caps == NULL) {
    GstPadTemplate *pad_template;

    pad_template =
        gst_element_class_get_pad_template (GST_ELEMENT_CLASS (bclass), "src");
    if (pad_template != NULL) {
      caps = gst_caps_ref (gst_pad_template_get_caps (pad_template));
    }
  }
  return caps;
}

static void
gst_base_src_fixate (GstPad * pad, GstCaps * caps)
{
  GstBaseSrcClass *bclass;
  GstBaseSrc *bsrc;

  bsrc = GST_BASE_SRC (gst_pad_get_parent (pad));
  bclass = GST_BASE_SRC_GET_CLASS (bsrc);

  if (bclass->fixate)
    bclass->fixate (bsrc, caps);

  gst_object_unref (bsrc);
}

static gboolean
gst_base_src_default_query (GstBaseSrc * src, GstQuery * query)
{
  gboolean res;

  switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_POSITION:
    {
      GstFormat format;

      gst_query_parse_position (query, &format, NULL);
      switch (format) {
        case GST_FORMAT_PERCENT:
        {
          gint64 percent;
          gint64 position;
          gint64 duration;

          position = src->segment.last_stop;
          duration = src->segment.duration;

          if (position != -1 && duration != -1) {
            if (position < duration)
              percent = gst_util_uint64_scale (GST_FORMAT_PERCENT_MAX, position,
                  duration);
            else
              percent = GST_FORMAT_PERCENT_MAX;
          } else
            percent = -1;

          gst_query_set_position (query, GST_FORMAT_PERCENT, percent);
          res = TRUE;
          break;
        }
        default:
        {
          gint64 position;

          position = src->segment.last_stop;

          if (position != -1) {
            /* convert to requested format */
            res =
                gst_pad_query_convert (src->srcpad, src->segment.format,
                position, &format, &position);
          } else
            res = TRUE;

          gst_query_set_position (query, format, position);
          break;
        }
      }
      break;
    }
    case GST_QUERY_DURATION:
    {
      GstFormat format;

      gst_query_parse_duration (query, &format, NULL);

      GST_DEBUG_OBJECT (src, "duration query in format %s",
          gst_format_get_name (format));
      switch (format) {
        case GST_FORMAT_PERCENT:
          gst_query_set_duration (query, GST_FORMAT_PERCENT,
              GST_FORMAT_PERCENT_MAX);
          res = TRUE;
          break;
        default:
        {
          gint64 duration;

          /* this is the duration as configured by the subclass. */
          duration = src->segment.duration;

          if (duration != -1) {
            /* convert to requested format, if this fails, we have a duration
             * but we cannot answer the query, we must return FALSE. */
            res =
                gst_pad_query_convert (src->srcpad, src->segment.format,
                duration, &format, &duration);
          } else {
            /* The subclass did not configure a duration, we assume that the
             * media has an unknown duration then and we return TRUE to report
             * this. Note that this is not the same as returning FALSE, which
             * means that we cannot report the duration at all. */
            res = TRUE;
          }
          gst_query_set_duration (query, format, duration);
          break;
        }
      }
      break;
    }

    case GST_QUERY_SEEKING:
    {
      gst_query_set_seeking (query, src->segment.format,
          src->seekable, 0, src->segment.duration);
      res = TRUE;
      break;
    }
    case GST_QUERY_SEGMENT:
    {
      gint64 start, stop;

      /* no end segment configured, current duration then */
      if ((stop = src->segment.stop) == -1)
        stop = src->segment.duration;
      start = src->segment.start;

      /* adjust to stream time */
      if (src->segment.time != -1) {
        start -= src->segment.time;
        if (stop != -1)
          stop -= src->segment.time;
      }
      gst_query_set_segment (query, src->segment.rate, src->segment.format,
          start, stop);
      res = TRUE;
      break;
    }

    case GST_QUERY_FORMATS:
    {
      gst_query_set_formats (query, 3, GST_FORMAT_DEFAULT,
          GST_FORMAT_BYTES, GST_FORMAT_PERCENT);
      res = TRUE;
      break;
    }
    case GST_QUERY_CONVERT:
    {
      GstFormat src_fmt, dest_fmt;
      gint64 src_val, dest_val;

      gst_query_parse_convert (query, &src_fmt, &src_val, &dest_fmt, &dest_val);

      /* we can only convert between equal formats... */
      if (src_fmt == dest_fmt) {
        dest_val = src_val;