gstbasetransform.c

gnash 在pc和嵌入式下开发需要的源码

  }

done:
  if (out_caps)
    gst_caps_unref (out_caps);

  trans->delay_configure = FALSE;

  return ret;
}

/* Given @caps calcultate the size of one unit.
 *
 * For video caps, this is the size of one frame (and thus one buffer).
 * For audio caps, this is the size of one sample.
 *
 * These values are cached since they do not change and the calculation
 * potentially involves parsing caps and other expensive stuff.
 *
 * We have two cache locations to store the size, one for the source caps
 * and one for the sink caps.
 *
 * this function returns FALSE if no size could be calculated.
 */
static gboolean
gst_base_transform_get_unit_size (GstBaseTransform * trans, GstCaps * caps,
    guint * size)
{
  gboolean res = FALSE;
  GstBaseTransformClass *bclass;

  /* see if we have the result cached */
  if (trans->cache_caps1 == caps) {
    *size = trans->cache_caps1_size;
    GST_DEBUG_OBJECT (trans, "returned %d from first cache", *size);
    return TRUE;
  }
  if (trans->cache_caps2 == caps) {
    *size = trans->cache_caps2_size;
    GST_DEBUG_OBJECT (trans, "returned %d from second cached", *size);
    return TRUE;
  }

  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
  if (bclass->get_unit_size) {
    res = bclass->get_unit_size (trans, caps, size);
    GST_DEBUG_OBJECT (trans, "caps %" GST_PTR_FORMAT
        ") has unit size %d, result %s", caps, *size, res ? "TRUE" : "FALSE");

    if (res) {
      /* and cache the values */
      if (trans->cache_caps1 == NULL) {
        gst_caps_replace (&trans->cache_caps1, caps);
        trans->cache_caps1_size = *size;
        GST_DEBUG_OBJECT (trans, "caching %d in first cache", *size);
      } else if (trans->cache_caps2 == NULL) {
        gst_caps_replace (&trans->cache_caps2, caps);
        trans->cache_caps2_size = *size;
        GST_DEBUG_OBJECT (trans, "caching %d in second cache", *size);
      } else {
        GST_DEBUG_OBJECT (trans, "no free spot to cache unit_size");
      }
    }
  } else {
    GST_DEBUG_OBJECT (trans, "Sub-class does not implement get_unit_size");
  }
  return res;
}

/* your upstream peer wants to send you a buffer
 * that buffer has the given offset, size and caps
 * you're requested to allocate a buffer
 */
static GstFlowReturn
gst_base_transform_buffer_alloc (GstPad * pad, guint64 offset, guint size,
    GstCaps * caps, GstBuffer ** buf)
{
  GstBaseTransform *trans;
  GstFlowReturn res;
  guint new_size;
  gboolean issinkcaps = TRUE;

  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));

  /* we cannot run this when we are transforming data and as such doing 
   * another negotiation in the transform method. */
  g_mutex_lock (trans->transform_lock);

  *buf = NULL;

  GST_DEBUG_OBJECT (trans, "allocating a buffer of size %d ...", size);
  if (offset == GST_BUFFER_OFFSET_NONE)
    GST_DEBUG_OBJECT (trans, "... and offset NONE");
  else
    GST_DEBUG_OBJECT (trans, "... and offset %" G_GUINT64_FORMAT, offset);

  /* if have_same_caps was previously set to TRUE we need to double check if it
   * hasn't changed */
  if (trans->have_same_caps) {
    GstCaps *sinkcaps;

    GST_OBJECT_LOCK (trans->sinkpad);
    sinkcaps = GST_PAD_CAPS (trans->sinkpad);
    issinkcaps = sinkcaps && (gst_caps_is_equal (sinkcaps, caps));
    GST_OBJECT_UNLOCK (trans->sinkpad);
  }

  /* before any buffers are pushed, have_same_caps is TRUE; allocating can trigger
   * a renegotiation and change that to FALSE */

  /* bilboed: This seems wrong, from all debug logs, have_same_caps is
   * initialized to FALSE */

  /* checking against trans->have_same_caps is not enough !! It should also
   *  check to see if the requested caps are equal to the sink caps */
  if (trans->have_same_caps && issinkcaps) {
    /* request a buffer with the same caps */
    GST_DEBUG_OBJECT (trans, "requesting buffer with same caps, size %d", size);

    res =
        gst_pad_alloc_buffer_and_set_caps (trans->srcpad, offset, size, caps,
        buf);
  } else {
    /* if we are configured, request a buffer with the src caps */
    GstCaps *srccaps;
    GstCaps *sinkcaps;
    gboolean configured;

    /* take lock, peek if the caps are ok */
    GST_OBJECT_LOCK (trans->sinkpad);
    sinkcaps = GST_PAD_CAPS (trans->sinkpad);
    configured = (sinkcaps == NULL || gst_caps_is_equal (sinkcaps, caps));
    GST_OBJECT_UNLOCK (trans->sinkpad);
    if (!configured)
      goto not_configured;

    /* take lock on srcpad to grab the caps, caps can change when pushing a
     * buffer. */
    GST_OBJECT_LOCK (trans->srcpad);
    if ((srccaps = GST_PAD_CAPS (trans->srcpad)))
      gst_caps_ref (srccaps);
    GST_OBJECT_UNLOCK (trans->srcpad);
    if (!srccaps)
      goto not_configured;

    GST_DEBUG_OBJECT (trans, "calling transform_size");
    if (!gst_base_transform_transform_size (trans,
            GST_PAD_DIRECTION (pad), caps, size, srccaps, &new_size)) {
      gst_caps_unref (srccaps);
      goto unknown_size;
    }

    res =
        gst_pad_alloc_buffer_and_set_caps (trans->srcpad, offset, new_size,
        srccaps, buf);

    gst_caps_unref (srccaps);
  }

  if (res == GST_FLOW_OK && !trans->have_same_caps) {
    /* note that we might have had same caps before, but calling the
       alloc_buffer caused setcaps to switch us out of in_place -- in any case
       the alloc_buffer served to transmit caps information but we can't use the
       buffer. fall through and allocate a buffer corresponding to our sink
       caps, if any */
    GstCaps *sinkcaps;
    GstCaps *srccaps;

    GST_OBJECT_LOCK (trans->sinkpad);
    if ((sinkcaps = GST_PAD_CAPS (trans->sinkpad)))
      gst_caps_ref (sinkcaps);
    GST_OBJECT_UNLOCK (trans->sinkpad);
    if (!sinkcaps)
      goto not_configured;

    GST_OBJECT_LOCK (trans->srcpad);
    if ((srccaps = GST_PAD_CAPS (trans->srcpad)))
      gst_caps_ref (srccaps);
    GST_OBJECT_UNLOCK (trans->srcpad);
    if (!srccaps) {
      gst_caps_unref (sinkcaps);
      goto not_configured;
    }

    if (!gst_base_transform_transform_size (trans,
            GST_PAD_DIRECTION (trans->srcpad), srccaps, GST_BUFFER_SIZE (*buf),
            sinkcaps, &new_size)) {
      gst_caps_unref (srccaps);
      gst_caps_unref (sinkcaps);
      goto unknown_size;
    }
    /* don't need the caps anymore now */
    gst_caps_unref (srccaps);

    gst_buffer_unref (*buf);

    *buf = gst_buffer_new_and_alloc (new_size);
    GST_BUFFER_OFFSET (*buf) = offset;
    /* set caps, gives away the ref */
    GST_BUFFER_CAPS (*buf) = sinkcaps;

    res = GST_FLOW_OK;
  }

done:
  g_mutex_unlock (trans->transform_lock);
  gst_object_unref (trans);

  return res;

not_configured:
  {
    /* let the default allocator handle it... */
    GST_DEBUG_OBJECT (trans, "not configured");
    gst_buffer_replace (buf, NULL);
    if (trans->passthrough) {
      /* ...by calling alloc_buffer without setting caps on the src pad, which
       * will force negotiation in the chain function. */
      res = gst_pad_alloc_buffer (trans->srcpad, offset, size, caps, buf);
    } else {
      /* ...by letting the default handler create a buffer */
      res = GST_FLOW_OK;
    }
    goto done;
  }
unknown_size:
  {
    /* let the default allocator handle it... */
    GST_DEBUG_OBJECT (trans, "unknown size");
    gst_buffer_replace (buf, NULL);
    if (trans->passthrough) {
      /* ...by calling alloc_buffer without setting caps on the src pad, which
       * will force negotiation in the chain function. */
      res = gst_pad_alloc_buffer (trans->srcpad, offset, size, caps, buf);
    } else {
      /* ...by letting the default handler create a buffer */
      res = GST_FLOW_OK;
    }
    goto done;
  }
}

static gboolean
gst_base_transform_sink_event (GstPad * pad, GstEvent * event)
{
  GstBaseTransform *trans;
  GstBaseTransformClass *bclass;
  gboolean ret = TRUE;
  gboolean forward = TRUE;

  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);

  if (bclass->event)
    forward = bclass->event (trans, event);

  /* FIXME, do this in the default event handler so the subclass can do
   * something different. */
  if (forward)
    ret = gst_pad_push_event (trans->srcpad, event);

  gst_object_unref (trans);

  return ret;
}

static gboolean
gst_base_transform_sink_eventfunc (GstBaseTransform * trans, GstEvent * event)
{
  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_FLUSH_START:
      break;
    case GST_EVENT_FLUSH_STOP:
      GST_OBJECT_LOCK (trans);
      /* reset QoS parameters */
      trans->priv->proportion = 1.0;
      trans->priv->earliest_time = -1;
      trans->priv->discont = FALSE;
      GST_OBJECT_UNLOCK (trans);
      /* we need new segment info after the flush. */
      trans->have_newsegment = FALSE;
      gst_segment_init (&trans->segment, GST_FORMAT_UNDEFINED);
      break;
    case GST_EVENT_EOS:
      break;
    case GST_EVENT_TAG:
      break;
    case GST_EVENT_NEWSEGMENT:
    {
      GstFormat format;
      gdouble rate, arate;
      gint64 start, stop, time;
      gboolean update;

      gst_event_parse_new_segment_full (event, &update, &rate, &arate, &format,
          &start, &stop, &time);

      trans->have_newsegment = TRUE;

      gst_segment_set_newsegment_full (&trans->segment, update, rate, arate,
          format, start, stop, time);

      if (format == GST_FORMAT_TIME) {
        GST_DEBUG_OBJECT (trans, "received TIME NEW_SEGMENT %" GST_TIME_FORMAT
            " -- %" GST_TIME_FORMAT ", time %" GST_TIME_FORMAT
            ", accum %" GST_TIME_FORMAT,
            GST_TIME_ARGS (trans->segment.start),
            GST_TIME_ARGS (trans->segment.stop),
            GST_TIME_ARGS (trans->segment.time),
            GST_TIME_ARGS (trans->segment.accum));
      } else {
        GST_DEBUG_OBJECT (trans, "received NEW_SEGMENT %" G_GINT64_FORMAT
            " -- %" G_GINT64_FORMAT ", time %" G_GINT64_FORMAT
            ", accum %" G_GINT64_FORMAT,
            trans->segment.start, trans->segment.stop,
            trans->segment.time, trans->segment.accum);
      }
      break;
    }
    default:
      break;
  }

  return TRUE;
}

static gboolean
gst_base_transform_src_event (GstPad * pad, GstEvent * event)
{
  GstBaseTransform *trans;
  GstBaseTransformClass *bclass;
  gboolean ret = TRUE;

  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);

  if (bclass->src_event)
    ret = bclass->src_event (trans, event);

  gst_object_unref (trans);

  return ret;
}

static gboolean
gst_base_transform_src_eventfunc (GstBaseTransform * trans, GstEvent * event)
{
  gboolean ret;

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_SEEK:
      break;
    case GST_EVENT_NAVIGATION:
      break;
    case GST_EVENT_QOS:
    {
      gdouble proportion;
      GstClockTimeDiff diff;
      GstClockTime timestamp;

      gst_event_parse_qos (event, &proportion, &diff, &timestamp);
      gst_base_transform_update_qos (trans, proportion, diff, timestamp);
      break;
    }
    default:
      break;
  }

  ret = gst_pad_push_event (trans->sinkpad, event);

  return ret;
}

static GstFlowReturn
gst_base_transform_handle_buffer (GstBaseTransform * trans, GstBuffer * inbuf,
    GstBuffer ** outbuf)
{
  GstBaseTransformClass *bclass;
  GstFlowReturn ret = GST_FLOW_OK;
  guint out_size;
  gboolean want_in_place;
  GstClockTime qostime;

  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);

  if (GST_BUFFER_OFFSET_IS_VALID (inbuf))
    GST_LOG_OBJECT (trans, "handling buffer %p of size %d and offset %"
        G_GUINT64_FORMAT, inbuf, GST_BUFFER_SIZE (inbuf),
        GST_BUFFER_OFFSET (inbuf));
  else
    GST_LOG_OBJECT (trans, "handling buffer %p of size %d and offset NONE",
        inbuf, GST_BUFFER_SIZE (inbuf));

  /* Don't allow buffer handling before negotiation, except in passthrough mode
   * or if the class doesn't implement a set_caps function (in which case it doesn't
   * care about caps)
   */
  if (!trans->negotiated && !trans->passthrough && (bclass->set_caps != NULL))
    goto not_negotiated;

  /* Set discont flag so we can mark the outgoing buffer */
  if (GST_BUFFER_IS_DISCONT (inbuf)) {
    GST_LOG_OBJECT (trans, "got DISCONT buffer %p", inbuf);
    trans->priv->discont = TRUE;
  }

  /* can only do QoS if the segment is in TIME */
  if (trans->segment.format != GST_FORMAT_TIME)
    goto no_qos;

  qostime = gst_segment_to_running_time (&trans->segment, GST_FORMAT_TIME,
      GST_BUFFER_TIMESTAMP (inbuf));

  if (qostime != -1) {
    gboolean need_skip;
    GstClockTime earliest_time;

    GST_OBJECT_LOCK (trans);
    earliest_time = trans->priv->earliest_time;
    /* check for QoS, don't perform conversion for buffers
     * that are known to be late. */
    need_skip = trans->priv->qos_enabled &&
        earliest_time != -1 && qostime != -1 && qostime <= earliest_time;
    GST_OBJECT_UNLOCK (trans);

    if (need_skip) {
      GST_CAT_DEBUG_OBJECT (GST_CAT_QOS, trans, "skipping transform: qostime %"
          GST_TIME_FORMAT " <= %" GST_TIME_FORMAT,
          GST_TIME_ARGS (qostime), GST_TIME_ARGS (earliest_time));
      /* mark discont for next buffer */
      trans->priv->discont = TRUE;
      goto skip;
    }
  }

no_qos:
  if (trans->passthrough) {
    /* In passthrough mode, give transform_ip a look at the
     * buffer, without making it writable, or just push the
     * data through */
    GST_LOG_OBJECT (trans, "element is in passthrough mode");

    if (bclass->transform_ip)
      ret = bclass->transform_ip (trans, inbuf);

    *outbuf = inbuf;

    goto done;
  }

  want_in_place = (bclass->transform_ip != NULL) && trans->always_in_place;
  *outbuf = NULL;

  if (want_in_place) {
    /* If want_in_place is TRUE, we may need to prepare a new output buffer
     * Sub-classes can implement a prepare_output_buffer function as they
     * wish. */
    GST_LOG_OBJECT (trans, "doing inplace transform");

    ret = gst_base_transform_prepare_output_buffer (trans, inbuf,
        GST_BUFFER_SIZE (inbuf), GST_PAD_CAPS (trans->srcpad), outbuf);
    if (G_UNLIKELY (ret != GST_FLOW_OK))
      goto no_buffer;

    ret = bclass->transform_ip (trans, *outbuf);

  } else {
    GST_LOG_OBJECT (trans, "doing non-inplace transform");

    /* not transforming inplace, figure out the output size */
    if (trans->always_in_place) {
      out_size = GST_BUFFER_SIZE (inbuf);
    } else {
      if (!gst_base_transform_transform_size (trans,
              GST_PAD_DIRECTION (trans->sinkpad), GST_PAD_CAPS (trans->sinkpad),
              GST_BUFFER_SIZE (inbuf), GST_PAD_CAPS (trans->srcpad),
              &out_size)) {
        /* we have an error */
        goto no_size;
      }
    }

    /* no in place transform, get buffer, this might renegotiate. */
    ret = gst_base_transform_prepare_output_buffer (trans, inbuf, out_size,
        GST_PAD_CAPS (trans->srcpad), outbuf);
    if (ret != GST_FLOW_OK)
      goto no_buffer;