static GstFlowReturn
gst_v4l2_video_dec_finish (GstVideoDecoder * decoder)
{
  GstV4l2VideoDec *self = GST_V4L2_VIDEO_DEC (decoder);
  GstFlowReturn ret = GST_FLOW_OK;
  GstBuffer *buffer;

  if (!g_atomic_int_get (&self->processing))
    goto done;

  GST_DEBUG_OBJECT (self, "Finishing decoding");

  GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);

  if (gst_v4l2_decoder_cmd (self->v4l2output, V4L2_DEC_CMD_STOP, 0)) {
    GstTask *task = decoder->srcpad->task;

    /* If the decoder stop command succeeded, just wait until processing is
     * finished */
    GST_OBJECT_LOCK (task);
    while (GST_TASK_STATE (task) == GST_TASK_STARTED)
      GST_TASK_WAIT (task);
    GST_OBJECT_UNLOCK (task);
    ret = GST_FLOW_FLUSHING;
  } else {
    /* otherwise keep queuing empty buffers until the processing thread has
     * stopped, _pool_process() will return FLUSHING when that happened */
    while (ret == GST_FLOW_OK) {
      buffer = gst_buffer_new ();
      ret =
          gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (self->
              v4l2output->pool), &buffer);
      gst_buffer_unref (buffer);
    }
  }

  /* and ensure the processing thread has stopped in case another error
   * occured. */
  gst_v4l2_object_unlock (self->v4l2capture);
  gst_pad_stop_task (decoder->srcpad);
  GST_VIDEO_DECODER_STREAM_LOCK (decoder);

  if (ret == GST_FLOW_FLUSHING)
    ret = self->output_flow;

  GST_DEBUG_OBJECT (decoder, "Done draining buffers");

done:
  return ret;
}
static GstFlowReturn
gst_v4l2_video_dec_finish (GstVideoDecoder * decoder)
{
  GstV4l2VideoDec *self = GST_V4L2_VIDEO_DEC (decoder);
  GstFlowReturn ret = GST_FLOW_OK;
  GstBuffer *buffer;

  if (!g_atomic_int_get (&self->processing))
    goto done;

  GST_DEBUG_OBJECT (self, "Finishing decoding");

  /* Keep queuing empty buffers until the processing thread has stopped,
   * _pool_process() will return FLUSHING when that happened */
  GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
  while (ret == GST_FLOW_OK) {
    buffer = gst_buffer_new ();
    ret =
        gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (self->
            v4l2output->pool), &buffer);
    gst_buffer_unref (buffer);
  }

  /* and ensure the processing thread has stopped in case another error
   * occured. */
  gst_v4l2_object_unlock (self->v4l2capture);
  gst_pad_stop_task (decoder->srcpad);
  GST_VIDEO_DECODER_STREAM_LOCK (decoder);

  if (ret == GST_FLOW_FLUSHING)
    ret = self->output_flow;

  GST_DEBUG_OBJECT (decoder, "Done draining buffers");

done:
  return ret;
}
Exemple #3
0
/* called after A/V sync to render frame */
static GstFlowReturn
gst_v4l2sink_show_frame (GstBaseSink * bsink, GstBuffer * buf)
{
  GstFlowReturn ret;
  GstV4l2Sink *v4l2sink = GST_V4L2SINK (bsink);
  GstV4l2Object *obj = v4l2sink->v4l2object;

  GST_DEBUG_OBJECT (v4l2sink, "render buffer: %p", buf);

  if (G_UNLIKELY (obj->pool == NULL))
    goto not_negotiated;

  ret =
      gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL_CAST (obj->pool), buf);

  return ret;

  /* ERRORS */
not_negotiated:
  {
    GST_ERROR_OBJECT (bsink, "not negotiated");
    return GST_FLOW_NOT_NEGOTIATED;
  }
}
static GstFlowReturn
gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
{
  GstV4l2Src *v4l2src = GST_V4L2SRC (src);
  GstV4l2Object *obj = v4l2src->v4l2object;
  GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL_CAST (obj->pool);
  GstFlowReturn ret;
  GstClock *clock;
  GstClockTime abs_time, base_time, timestamp, duration;
  GstClockTime delay;

  do {
    ret = GST_BASE_SRC_CLASS (parent_class)->alloc (GST_BASE_SRC (src), 0,
        obj->info.size, buf);

    if (G_UNLIKELY (ret != GST_FLOW_OK))
      goto alloc_failed;

    ret = gst_v4l2_buffer_pool_process (pool, buf);

  } while (ret == GST_V4L2_FLOW_CORRUPTED_BUFFER);

  if (G_UNLIKELY (ret != GST_FLOW_OK))
    goto error;

  timestamp = GST_BUFFER_TIMESTAMP (*buf);
  duration = obj->duration;

  /* timestamps, LOCK to get clock and base time. */
  /* FIXME: element clock and base_time is rarely changing */
  GST_OBJECT_LOCK (v4l2src);
  if ((clock = GST_ELEMENT_CLOCK (v4l2src))) {
    /* we have a clock, get base time and ref clock */
    base_time = GST_ELEMENT (v4l2src)->base_time;
    gst_object_ref (clock);
  } else {
    /* no clock, can't set timestamps */
    base_time = GST_CLOCK_TIME_NONE;
  }
  GST_OBJECT_UNLOCK (v4l2src);

  /* sample pipeline clock */
  if (clock) {
    abs_time = gst_clock_get_time (clock);
    gst_object_unref (clock);
  } else {
    abs_time = GST_CLOCK_TIME_NONE;
  }

  if (timestamp != GST_CLOCK_TIME_NONE) {
    struct timespec now;
    GstClockTime gstnow;

    /* v4l2 specs say to use the system time although many drivers switched to
     * the more desirable monotonic time. We first try to use the monotonic time
     * and see how that goes */
    clock_gettime (CLOCK_MONOTONIC, &now);
    gstnow = GST_TIMESPEC_TO_TIME (now);

    if (gstnow < timestamp && (timestamp - gstnow) > (10 * GST_SECOND)) {
      GTimeVal now;

      /* very large diff, fall back to system time */
      g_get_current_time (&now);
      gstnow = GST_TIMEVAL_TO_TIME (now);
    }

    if (gstnow > timestamp) {
      delay = gstnow - timestamp;
    } else {
      delay = 0;
    }

    GST_DEBUG_OBJECT (v4l2src, "ts: %" GST_TIME_FORMAT " now %" GST_TIME_FORMAT
        " delay %" GST_TIME_FORMAT, GST_TIME_ARGS (timestamp),
        GST_TIME_ARGS (gstnow), GST_TIME_ARGS (delay));
  } else {
    /* we assume 1 frame latency otherwise */
    if (GST_CLOCK_TIME_IS_VALID (duration))
      delay = duration;
    else
      delay = 0;
  }

  /* set buffer metadata */
  GST_BUFFER_OFFSET (*buf) = v4l2src->offset++;
  GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset;

  if (G_LIKELY (abs_time != GST_CLOCK_TIME_NONE)) {
    /* the time now is the time of the clock minus the base time */
    timestamp = abs_time - base_time;

    /* adjust for delay in the device */
    if (timestamp > delay)
      timestamp -= delay;
    else
      timestamp = 0;
  } else {
    timestamp = GST_CLOCK_TIME_NONE;
  }

  /* activate settings for next frame */
  if (GST_CLOCK_TIME_IS_VALID (duration)) {
    v4l2src->ctrl_time += duration;
  } else {
    /* this is not very good (as it should be the next timestamp),
     * still good enough for linear fades (as long as it is not -1)
     */
    v4l2src->ctrl_time = timestamp;
  }
  gst_object_sync_values (GST_OBJECT (src), v4l2src->ctrl_time);

  GST_INFO_OBJECT (src, "sync to %" GST_TIME_FORMAT " out ts %" GST_TIME_FORMAT,
      GST_TIME_ARGS (v4l2src->ctrl_time), GST_TIME_ARGS (timestamp));

  GST_BUFFER_TIMESTAMP (*buf) = timestamp;
  GST_BUFFER_DURATION (*buf) = duration;

  return ret;

  /* ERROR */
alloc_failed:
  {
    if (ret != GST_FLOW_FLUSHING)
      GST_ELEMENT_ERROR (src, RESOURCE, NO_SPACE_LEFT,
          ("Failed to allocate a buffer"), (NULL));
    return ret;
  }
error:
  {
    if (ret == GST_V4L2_FLOW_LAST_BUFFER) {
      GST_ELEMENT_ERROR (src, RESOURCE, FAILED,
          ("Driver returned a buffer with no payload, this most likely "
              "indicate a bug in the driver."), (NULL));
      ret = GST_FLOW_ERROR;
    } else {
      GST_DEBUG_OBJECT (src, "error processing buffer %d (%s)", ret,
          gst_flow_get_name (ret));
    }
    return ret;
  }
}
static GstFlowReturn
gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
{
  GstV4l2Src *v4l2src = GST_V4L2SRC (src);
  GstV4l2Object *obj = v4l2src->v4l2object;
  GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL_CAST (obj->pool);
  GstFlowReturn ret;
  GstClock *clock;
  GstClockTime abs_time, base_time, timestamp, duration;
  GstClockTime delay;
  GstMessage *qos_msg;

  do {
    ret = GST_BASE_SRC_CLASS (parent_class)->alloc (GST_BASE_SRC (src), 0,
        obj->info.size, buf);

    if (G_UNLIKELY (ret != GST_FLOW_OK))
      goto alloc_failed;

    ret = gst_v4l2_buffer_pool_process (pool, buf);

  } while (ret == GST_V4L2_FLOW_CORRUPTED_BUFFER);

  if (G_UNLIKELY (ret != GST_FLOW_OK))
    goto error;

  timestamp = GST_BUFFER_TIMESTAMP (*buf);
  duration = obj->duration;

  /* timestamps, LOCK to get clock and base time. */
  /* FIXME: element clock and base_time is rarely changing */
  GST_OBJECT_LOCK (v4l2src);
  if ((clock = GST_ELEMENT_CLOCK (v4l2src))) {
    /* we have a clock, get base time and ref clock */
    base_time = GST_ELEMENT (v4l2src)->base_time;
    gst_object_ref (clock);
  } else {
    /* no clock, can't set timestamps */
    base_time = GST_CLOCK_TIME_NONE;
  }
  GST_OBJECT_UNLOCK (v4l2src);

  /* sample pipeline clock */
  if (clock) {
    abs_time = gst_clock_get_time (clock);
    gst_object_unref (clock);
  } else {
    abs_time = GST_CLOCK_TIME_NONE;
  }

retry:
  if (!v4l2src->has_bad_timestamp && timestamp != GST_CLOCK_TIME_NONE) {
    struct timespec now;
    GstClockTime gstnow;

    /* v4l2 specs say to use the system time although many drivers switched to
     * the more desirable monotonic time. We first try to use the monotonic time
     * and see how that goes */
    clock_gettime (CLOCK_MONOTONIC, &now);
    gstnow = GST_TIMESPEC_TO_TIME (now);

    if (timestamp > gstnow || (gstnow - timestamp) > (10 * GST_SECOND)) {
      GTimeVal now;

      /* very large diff, fall back to system time */
      g_get_current_time (&now);
      gstnow = GST_TIMEVAL_TO_TIME (now);
    }

    /* Detect buggy drivers here, and stop using their timestamp. Failing any
     * of these condition would imply a very buggy driver:
     *   - Timestamp in the future
     *   - Timestamp is going backward compare to last seen timestamp
     *   - Timestamp is jumping forward for less then a frame duration
     *   - Delay is bigger then the actual timestamp
     * */
    if (timestamp > gstnow) {
      GST_WARNING_OBJECT (v4l2src,
          "Timestamp in the future detected, ignoring driver timestamps");
      v4l2src->has_bad_timestamp = TRUE;
      goto retry;
    }

    if (v4l2src->last_timestamp > timestamp) {
      GST_WARNING_OBJECT (v4l2src,
          "Timestamp going backward, ignoring driver timestamps");
      v4l2src->has_bad_timestamp = TRUE;
      goto retry;
    }

    delay = gstnow - timestamp;

    if (delay > timestamp) {
      GST_WARNING_OBJECT (v4l2src,
          "Timestamp does not correlate with any clock, ignoring driver timestamps");
      v4l2src->has_bad_timestamp = TRUE;
      goto retry;
    }

    /* Save last timestamp for sanity checks */
    v4l2src->last_timestamp = timestamp;

    GST_DEBUG_OBJECT (v4l2src, "ts: %" GST_TIME_FORMAT " now %" GST_TIME_FORMAT
        " delay %" GST_TIME_FORMAT, GST_TIME_ARGS (timestamp),
        GST_TIME_ARGS (gstnow), GST_TIME_ARGS (delay));
  } else {
    /* we assume 1 frame latency otherwise */
    if (GST_CLOCK_TIME_IS_VALID (duration))
      delay = duration;
    else
      delay = 0;
  }

  /* set buffer metadata */

  if (G_LIKELY (abs_time != GST_CLOCK_TIME_NONE)) {
    /* the time now is the time of the clock minus the base time */
    timestamp = abs_time - base_time;

    /* adjust for delay in the device */
    if (timestamp > delay)
      timestamp -= delay;
    else
      timestamp = 0;
  } else {
    timestamp = GST_CLOCK_TIME_NONE;
  }

  /* activate settings for next frame */
  if (GST_CLOCK_TIME_IS_VALID (duration)) {
    v4l2src->ctrl_time += duration;
  } else {
    /* this is not very good (as it should be the next timestamp),
     * still good enough for linear fades (as long as it is not -1)
     */
    v4l2src->ctrl_time = timestamp;
  }
  gst_object_sync_values (GST_OBJECT (src), v4l2src->ctrl_time);

  GST_INFO_OBJECT (src, "sync to %" GST_TIME_FORMAT " out ts %" GST_TIME_FORMAT,
      GST_TIME_ARGS (v4l2src->ctrl_time), GST_TIME_ARGS (timestamp));

  /* use generated offset values only if there are not already valid ones
   * set by the v4l2 device */
  if (!GST_BUFFER_OFFSET_IS_VALID (*buf) || !GST_BUFFER_OFFSET_END_IS_VALID (*buf)) {
    GST_BUFFER_OFFSET (*buf) = v4l2src->offset++;
    GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset;
  } else {
    /* adjust raw v4l2 device sequence, will restart at null in case of renegotiation
     * (streamoff/streamon) */
    GST_BUFFER_OFFSET (*buf) += v4l2src->renegotiation_adjust;
    GST_BUFFER_OFFSET_END (*buf) += v4l2src->renegotiation_adjust;
    /* check for frame loss with given (from v4l2 device) buffer offset */
    if ((v4l2src->offset != 0) && (GST_BUFFER_OFFSET (*buf) != (v4l2src->offset + 1))) {
      guint64 lost_frame_count = GST_BUFFER_OFFSET (*buf) - v4l2src->offset - 1;
      GST_WARNING_OBJECT (v4l2src,
          "lost frames detected: count = %" G_GUINT64_FORMAT " - ts: %" GST_TIME_FORMAT,
              lost_frame_count, GST_TIME_ARGS (timestamp));

      qos_msg = gst_message_new_qos (GST_OBJECT_CAST (v4l2src), TRUE,
          GST_CLOCK_TIME_NONE, GST_CLOCK_TIME_NONE, timestamp,
          GST_CLOCK_TIME_IS_VALID (duration) ? lost_frame_count * duration : GST_CLOCK_TIME_NONE);
      gst_element_post_message (GST_ELEMENT_CAST (v4l2src), qos_msg);

    }
    v4l2src->offset = GST_BUFFER_OFFSET (*buf);
  }

  GST_BUFFER_TIMESTAMP (*buf) = timestamp;
  GST_BUFFER_DURATION (*buf) = duration;

  return ret;

  /* ERROR */
alloc_failed:
  {
    if (ret != GST_FLOW_FLUSHING)
      GST_ELEMENT_ERROR (src, RESOURCE, NO_SPACE_LEFT,
          ("Failed to allocate a buffer"), (NULL));
    return ret;
  }
error:
  {
    if (ret == GST_V4L2_FLOW_LAST_BUFFER) {
      GST_ELEMENT_ERROR (src, RESOURCE, FAILED,
          ("Driver returned a buffer with no payload, this most likely "
              "indicate a bug in the driver."), (NULL));
      ret = GST_FLOW_ERROR;
    } else {
      GST_DEBUG_OBJECT (src, "error processing buffer %d (%s)", ret,
          gst_flow_get_name (ret));
    }
    return ret;
  }
}
static GstFlowReturn
gst_v4l2_transform_prepare_output_buffer (GstBaseTransform * trans,
    GstBuffer * inbuf, GstBuffer ** outbuf)
{
  GstV4l2Transform *self = GST_V4L2_TRANSFORM (trans);
  GstBufferPool *pool = GST_BUFFER_POOL (self->v4l2output->pool);
  GstFlowReturn ret = GST_FLOW_OK;
  GstBaseTransformClass *bclass = GST_BASE_TRANSFORM_CLASS (parent_class);

  if (gst_base_transform_is_passthrough (trans)) {
    GST_DEBUG_OBJECT (self, "Passthrough, no need to do anything");
    *outbuf = inbuf;
    goto beach;
  }

  /* Ensure input internal pool is active */
  if (!gst_buffer_pool_is_active (pool)) {
    GstStructure *config = gst_buffer_pool_get_config (pool);
    gst_buffer_pool_config_set_params (config, self->incaps,
        self->v4l2output->info.size, 2, 2);

    /* There is no reason to refuse this config */
    if (!gst_buffer_pool_set_config (pool, config))
      goto activate_failed;

    if (!gst_buffer_pool_set_active (pool, TRUE))
      goto activate_failed;
  }

  GST_DEBUG_OBJECT (self, "Queue input buffer");
  ret = gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (pool), &inbuf);
  if (G_UNLIKELY (ret != GST_FLOW_OK))
    goto beach;

  do {
    pool = gst_base_transform_get_buffer_pool (trans);

    if (!gst_buffer_pool_set_active (pool, TRUE))
      goto activate_failed;

    GST_DEBUG_OBJECT (self, "Dequeue output buffer");
    ret = gst_buffer_pool_acquire_buffer (pool, outbuf, NULL);
    g_object_unref (pool);

    if (ret != GST_FLOW_OK)
      goto alloc_failed;

    pool = self->v4l2capture->pool;
    ret = gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (pool), outbuf);

  } while (ret == GST_V4L2_FLOW_CORRUPTED_BUFFER);

  if (ret != GST_FLOW_OK) {
    gst_buffer_unref (*outbuf);
    *outbuf = NULL;
  }

  if (bclass->copy_metadata)
    if (!bclass->copy_metadata (trans, inbuf, *outbuf)) {
      /* something failed, post a warning */
      GST_ELEMENT_WARNING (self, STREAM, NOT_IMPLEMENTED,
          ("could not copy metadata"), (NULL));
    }

beach:
  return ret;

activate_failed:
  GST_ELEMENT_ERROR (self, RESOURCE, SETTINGS,
      ("failed to activate bufferpool"), ("failed to activate bufferpool"));
  g_object_unref (pool);
  return GST_FLOW_ERROR;

alloc_failed:
  GST_DEBUG_OBJECT (self, "could not allocate buffer from pool");
  return ret;
}
static GstFlowReturn
gst_v4l2_video_dec_handle_frame (GstVideoDecoder * decoder,
    GstVideoCodecFrame * frame)
{
  GstV4l2VideoDec *self = GST_V4L2_VIDEO_DEC (decoder);
  GstFlowReturn ret = GST_FLOW_OK;

  GST_DEBUG_OBJECT (self, "Handling frame %d", frame->system_frame_number);

  if (G_UNLIKELY (!g_atomic_int_get (&self->active)))
    goto flushing;

  if (G_UNLIKELY (!GST_V4L2_IS_ACTIVE (self->v4l2output))) {
    if (!self->input_state)
      goto not_negotiated;
    if (!gst_v4l2_object_set_format (self->v4l2output, self->input_state->caps))
      goto not_negotiated;
  }

  if (G_UNLIKELY (!GST_V4L2_IS_ACTIVE (self->v4l2capture))) {
    GstBufferPool *pool = GST_BUFFER_POOL (self->v4l2output->pool);
    GstVideoInfo info;
    GstVideoCodecState *output_state;
    GstBuffer *codec_data;

    GST_DEBUG_OBJECT (self, "Sending header");

    codec_data = self->input_state->codec_data;

    /* We are running in byte-stream mode, so we don't know the headers, but
     * we need to send something, otherwise the decoder will refuse to
     * intialize.
     */
    if (codec_data) {
      gst_buffer_ref (codec_data);
    } else {
      codec_data = frame->input_buffer;
      frame->input_buffer = NULL;
    }

    /* Ensure input internal pool is active */
    if (!gst_buffer_pool_is_active (pool)) {
      GstStructure *config = gst_buffer_pool_get_config (pool);
      gst_buffer_pool_config_set_params (config, self->input_state->caps,
          self->v4l2output->info.size, 2, 2);

      /* There is no reason to refuse this config */
      if (!gst_buffer_pool_set_config (pool, config))
        goto activate_failed;

      if (!gst_buffer_pool_set_active (pool, TRUE))
        goto activate_failed;
    }

    GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
    ret =
        gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (self->
            v4l2output->pool), &codec_data);
    GST_VIDEO_DECODER_STREAM_LOCK (decoder);

    gst_buffer_unref (codec_data);

    if (!gst_v4l2_object_acquire_format (self->v4l2capture, &info))
      goto not_negotiated;

    output_state = gst_video_decoder_set_output_state (decoder,
        info.finfo->format, info.width, info.height, self->input_state);

    /* Copy the rest of the information, there might be more in the future */
    output_state->info.interlace_mode = info.interlace_mode;
    gst_video_codec_state_unref (output_state);

    if (!gst_video_decoder_negotiate (decoder)) {
      if (GST_PAD_IS_FLUSHING (decoder->srcpad))
        goto flushing;
      else
        goto not_negotiated;
    }

    /* Ensure our internal pool is activated */
    if (!gst_buffer_pool_set_active (GST_BUFFER_POOL (self->v4l2capture->pool),
            TRUE))
      goto activate_failed;
  }

  if (g_atomic_int_get (&self->processing) == FALSE) {
    /* It's possible that the processing thread stopped due to an error */
    if (self->output_flow != GST_FLOW_OK &&
        self->output_flow != GST_FLOW_FLUSHING) {
      GST_DEBUG_OBJECT (self, "Processing loop stopped with error, leaving");
      ret = self->output_flow;
      goto drop;
    }

    GST_DEBUG_OBJECT (self, "Starting decoding thread");

    /* Start the processing task, when it quits, the task will disable input
     * processing to unlock input if draining, or prevent potential block */
    g_atomic_int_set (&self->processing, TRUE);
    if (!gst_pad_start_task (decoder->srcpad,
            (GstTaskFunction) gst_v4l2_video_dec_loop, self,
            (GDestroyNotify) gst_v4l2_video_dec_loop_stopped))
      goto start_task_failed;
  }

  if (frame->input_buffer) {
    GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
    ret =
        gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (self->v4l2output->
            pool), &frame->input_buffer);
    GST_VIDEO_DECODER_STREAM_LOCK (decoder);

    if (ret == GST_FLOW_FLUSHING) {
      if (g_atomic_int_get (&self->processing) == FALSE)
        ret = self->output_flow;
      goto drop;
    } else if (ret != GST_FLOW_OK) {
      goto process_failed;
    }

    /* No need to keep input arround */
    gst_buffer_replace (&frame->input_buffer, NULL);
  }

  gst_video_codec_frame_unref (frame);
  return ret;

  /* ERRORS */
not_negotiated:
  {
    GST_ERROR_OBJECT (self, "not negotiated");
    ret = GST_FLOW_NOT_NEGOTIATED;
    goto drop;
  }
activate_failed:
  {
    GST_ELEMENT_ERROR (self, RESOURCE, SETTINGS,
        (_("Failed to allocate required memory.")),
        ("Buffer pool activation failed"));
    ret = GST_FLOW_ERROR;
    goto drop;
  }
flushing:
  {
    ret = GST_FLOW_FLUSHING;
    goto drop;
  }

start_task_failed:
  {
    GST_ELEMENT_ERROR (self, RESOURCE, FAILED,
        (_("Failed to start decoding thread.")), (NULL));
    g_atomic_int_set (&self->processing, FALSE);
    ret = GST_FLOW_ERROR;
    goto drop;
  }
process_failed:
  {
    GST_ELEMENT_ERROR (self, RESOURCE, FAILED,
        (_("Failed to process frame.")),
        ("Maybe be due to not enough memory or failing driver"));
    ret = GST_FLOW_ERROR;
    goto drop;
  }
drop:
  {
    gst_video_decoder_drop_frame (decoder, frame);
    return ret;
  }
}
static void
gst_v4l2_video_dec_loop (GstVideoDecoder * decoder)
{
  GstV4l2VideoDec *self = GST_V4L2_VIDEO_DEC (decoder);
  GstV4l2BufferPool *v4l2_pool = GST_V4L2_BUFFER_POOL (self->v4l2capture->pool);
  GstBufferPool *pool;
  GstVideoCodecFrame *frame;
  GstBuffer *buffer = NULL;
  GstFlowReturn ret;

  GST_LOG_OBJECT (decoder, "Allocate output buffer");

  do {
    /* We cannot use the base class allotate helper since it taking the internal
     * stream lock. we know that the acquire may need to poll until more frames
     * comes in and holding this lock would prevent that.
     */
    pool = gst_video_decoder_get_buffer_pool (decoder);

    /* Pool may be NULL if we started going to READY state */
    if (pool == NULL) {
      ret = GST_FLOW_FLUSHING;
      goto beach;
    }

    ret = gst_buffer_pool_acquire_buffer (pool, &buffer, NULL);
    g_object_unref (pool);

    if (ret != GST_FLOW_OK)
      goto beach;

    GST_LOG_OBJECT (decoder, "Process output buffer");
    ret = gst_v4l2_buffer_pool_process (v4l2_pool, &buffer);

  } while (ret == GST_V4L2_FLOW_CORRUPTED_BUFFER);

  if (ret != GST_FLOW_OK)
    goto beach;

  frame = gst_v4l2_video_dec_get_oldest_frame (decoder);

  if (frame) {
    frame->output_buffer = buffer;
    buffer = NULL;
    ret = gst_video_decoder_finish_frame (decoder, frame);

    if (ret != GST_FLOW_OK)
      goto beach;
  } else {
    GST_WARNING_OBJECT (decoder, "Decoder is producing too many buffers");
    gst_buffer_unref (buffer);
  }

  return;

beach:
  GST_DEBUG_OBJECT (decoder, "Leaving output thread: %s",
      gst_flow_get_name (ret));

  gst_buffer_replace (&buffer, NULL);
  self->output_flow = ret;
  g_atomic_int_set (&self->processing, FALSE);
  gst_v4l2_object_unlock (self->v4l2output);
  gst_pad_pause_task (decoder->srcpad);
}
static GstFlowReturn
gst_v4l2_video_dec_handle_frame (GstVideoDecoder * decoder,
    GstVideoCodecFrame * frame)
{
  GstV4l2Error error = GST_V4L2_ERROR_INIT;
  GstV4l2VideoDec *self = GST_V4L2_VIDEO_DEC (decoder);
  GstFlowReturn ret = GST_FLOW_OK;
  gboolean processed = FALSE;
  GstBuffer *tmp;

  GST_DEBUG_OBJECT (self, "Handling frame %d", frame->system_frame_number);

  if (G_UNLIKELY (!g_atomic_int_get (&self->active)))
    goto flushing;

  if (G_UNLIKELY (!GST_V4L2_IS_ACTIVE (self->v4l2output))) {
    if (!self->input_state)
      goto not_negotiated;
    if (!gst_v4l2_object_set_format (self->v4l2output, self->input_state->caps,
          &error))
      goto not_negotiated;
  }

  if (G_UNLIKELY (!GST_V4L2_IS_ACTIVE (self->v4l2capture))) {
    GstBufferPool *pool = GST_BUFFER_POOL (self->v4l2output->pool);
    GstVideoInfo info;
    GstVideoCodecState *output_state;
    GstBuffer *codec_data;
    GstCaps *acquired_caps, *available_caps, *caps, *filter;
    GstStructure *st;

    GST_DEBUG_OBJECT (self, "Sending header");

    codec_data = self->input_state->codec_data;

    /* We are running in byte-stream mode, so we don't know the headers, but
     * we need to send something, otherwise the decoder will refuse to
     * intialize.
     */
    if (codec_data) {
      gst_buffer_ref (codec_data);
    } else {
      codec_data = gst_buffer_ref (frame->input_buffer);
      processed = TRUE;
    }

    /* Ensure input internal pool is active */
    if (!gst_buffer_pool_is_active (pool)) {
      GstStructure *config = gst_buffer_pool_get_config (pool);
      gst_buffer_pool_config_set_params (config, self->input_state->caps,
          self->v4l2output->info.size, 2, 2);

      /* There is no reason to refuse this config */
      if (!gst_buffer_pool_set_config (pool, config))
        goto activate_failed;

      if (!gst_buffer_pool_set_active (pool, TRUE))
        goto activate_failed;
    }

    GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
    ret =
        gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (self->
            v4l2output->pool), &codec_data);
    GST_VIDEO_DECODER_STREAM_LOCK (decoder);

    gst_buffer_unref (codec_data);

    /* For decoders G_FMT returns coded size, G_SELECTION returns visible size
     * in the compose rectangle. gst_v4l2_object_acquire_format() checks both
     * and returns the visible size as with/height and the coded size as
     * padding. */
    if (!gst_v4l2_object_acquire_format (self->v4l2capture, &info))
      goto not_negotiated;

    /* Create caps from the acquired format, remove the format field */
    acquired_caps = gst_video_info_to_caps (&info);
    st = gst_caps_get_structure (acquired_caps, 0);
    gst_structure_remove_field (st, "format");

    /* Probe currently available pixel formats */
    available_caps = gst_v4l2_object_probe_caps (self->v4l2capture, NULL);
    available_caps = gst_caps_make_writable (available_caps);

    /* Replace coded size with visible size, we want to negotiate visible size
     * with downstream, not coded size. */
    gst_caps_map_in_place (available_caps, gst_v4l2_video_remove_padding, self);

    filter = gst_caps_intersect_full (available_caps, acquired_caps,
        GST_CAPS_INTERSECT_FIRST);
    gst_caps_unref (acquired_caps);
    gst_caps_unref (available_caps);
    caps = gst_pad_peer_query_caps (decoder->srcpad, filter);
    gst_caps_unref (filter);

    GST_DEBUG_OBJECT (self, "Possible decoded caps: %" GST_PTR_FORMAT, caps);
    if (gst_caps_is_empty (caps)) {
      gst_caps_unref (caps);
      goto not_negotiated;
    }

    /* Fixate pixel format */
    caps = gst_caps_fixate (caps);

    GST_DEBUG_OBJECT (self, "Chosen decoded caps: %" GST_PTR_FORMAT, caps);

    /* Try to set negotiated format, on success replace acquired format */
    if (gst_v4l2_object_set_format (self->v4l2capture, caps, &error))
      gst_video_info_from_caps (&info, caps);
    else
      gst_v4l2_clear_error (&error);
    gst_caps_unref (caps);

    output_state = gst_video_decoder_set_output_state (decoder,
        info.finfo->format, info.width, info.height, self->input_state);

    /* Copy the rest of the information, there might be more in the future */
    output_state->info.interlace_mode = info.interlace_mode;
    gst_video_codec_state_unref (output_state);

    if (!gst_video_decoder_negotiate (decoder)) {
      if (GST_PAD_IS_FLUSHING (decoder->srcpad))
        goto flushing;
      else
        goto not_negotiated;
    }

    /* Ensure our internal pool is activated */
    if (!gst_buffer_pool_set_active (GST_BUFFER_POOL (self->v4l2capture->pool),
            TRUE))
      goto activate_failed;
  }

  if (g_atomic_int_get (&self->processing) == FALSE) {
    /* It's possible that the processing thread stopped due to an error */
    if (self->output_flow != GST_FLOW_OK &&
        self->output_flow != GST_FLOW_FLUSHING) {
      GST_DEBUG_OBJECT (self, "Processing loop stopped with error, leaving");
      ret = self->output_flow;
      goto drop;
    }

    GST_DEBUG_OBJECT (self, "Starting decoding thread");

    /* Start the processing task, when it quits, the task will disable input
     * processing to unlock input if draining, or prevent potential block */
    g_atomic_int_set (&self->processing, TRUE);
    if (!gst_pad_start_task (decoder->srcpad,
            (GstTaskFunction) gst_v4l2_video_dec_loop, self,
            (GDestroyNotify) gst_v4l2_video_dec_loop_stopped))
      goto start_task_failed;
  }

  if (!processed) {
    GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
    ret =
        gst_v4l2_buffer_pool_process (GST_V4L2_BUFFER_POOL (self->v4l2output->
            pool), &frame->input_buffer);
    GST_VIDEO_DECODER_STREAM_LOCK (decoder);

    if (ret == GST_FLOW_FLUSHING) {
      if (g_atomic_int_get (&self->processing) == FALSE)
        ret = self->output_flow;
      goto drop;
    } else if (ret != GST_FLOW_OK) {
      goto process_failed;
    }
  }

  /* No need to keep input arround */
  tmp = frame->input_buffer;
  frame->input_buffer = gst_buffer_new ();
  gst_buffer_copy_into (frame->input_buffer, tmp,
      GST_BUFFER_COPY_FLAGS | GST_BUFFER_COPY_TIMESTAMPS |
      GST_BUFFER_COPY_META, 0, 0);
  gst_buffer_unref (tmp);

  gst_video_codec_frame_unref (frame);
  return ret;

  /* ERRORS */
not_negotiated:
  {
    GST_ERROR_OBJECT (self, "not negotiated");
    ret = GST_FLOW_NOT_NEGOTIATED;
    gst_v4l2_error (self, &error);
    goto drop;
  }
activate_failed:
  {
    GST_ELEMENT_ERROR (self, RESOURCE, SETTINGS,
        (_("Failed to allocate required memory.")),
        ("Buffer pool activation failed"));
    ret = GST_FLOW_ERROR;
    goto drop;
  }
flushing:
  {
    ret = GST_FLOW_FLUSHING;
    goto drop;
  }

start_task_failed:
  {
    GST_ELEMENT_ERROR (self, RESOURCE, FAILED,
        (_("Failed to start decoding thread.")), (NULL));
    g_atomic_int_set (&self->processing, FALSE);
    ret = GST_FLOW_ERROR;
    goto drop;
  }
process_failed:
  {
    GST_ELEMENT_ERROR (self, RESOURCE, FAILED,
        (_("Failed to process frame.")),
        ("Maybe be due to not enough memory or failing driver"));
    ret = GST_FLOW_ERROR;
    goto drop;
  }
drop:
  {
    gst_video_decoder_drop_frame (decoder, frame);
    return ret;
  }
}