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pad: add pull mode probes
Allow probes to inspect the offset and size from a probe in pull mode and allow the probe to modify the buffer. Update design doc a little.
This commit is contained in:
Wim Taymans
parent
ba3028aeeb
commit
ce09010267
3 changed files with 102 additions and 61 deletions
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@ -45,20 +45,22 @@ Overview
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typedef enum
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{
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GST_PAD_PROBE_TYPE_INVALID = 0,
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GST_PAD_PROBE_TYPE_INVALID = 0,
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/* flags to control blocking */
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GST_PAD_PROBE_TYPE_IDLE = (1 << 0),
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GST_PAD_PROBE_TYPE_BLOCK = (1 << 1),
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GST_PAD_PROBE_TYPE_IDLE = (1 << 0),
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GST_PAD_PROBE_TYPE_BLOCK = (1 << 1),
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/* flags to select datatypes */
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GST_PAD_PROBE_TYPE_BUFFER = (1 << 2),
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GST_PAD_PROBE_TYPE_BUFFER_LIST = (1 << 3),
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GST_PAD_PROBE_TYPE_EVENT = (1 << 4),
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GST_PAD_PROBE_TYPE_BUFFER = (1 << 2),
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GST_PAD_PROBE_TYPE_BUFFER_LIST = (1 << 3),
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GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM = (1 << 4),
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GST_PAD_PROBE_TYPE_EVENT_UPSTREAM = (1 << 5),
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/* flags to select scheduling mode */
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GST_PAD_PROBE_TYPE_PUSH = (1 << 5),
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GST_PAD_PROBE_TYPE_PULL = (1 << 6),
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GST_PAD_PROBE_TYPE_PUSH = (1 << 6),
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GST_PAD_PROBE_TYPE_PULL = (1 << 7),
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} GstPadProbeType;
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When adding a probe with the IDLE or BLOCK flag, the probe will become a
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@ -71,14 +73,13 @@ Overview
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The probe callback is defined as:
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GstPadProbeReturn (*GstPadProbeCallback) (GstPad *pad, GstPadProbeType type,
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gpointer type_data,
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GstPadProbeReturn (*GstPadProbeCallback) (GstPad *pad, GstPadProbeInfo *info,
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gpointer user_data);
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The executing probe type is passed as an argument and is guaranteed to match
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the mask that was used to register the callback. type_data contains type
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specific data, which is usually the data item that is blocked or NULL when
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no data item is present.
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A probe info structure is passed as an argument and its type is guaranteed
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to match the mask that was used to register the callback. The data item in the
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info contains type specific data, which is usually the data item that is blocked
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or NULL when no data item is present.
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The probe can return any of the following return values:
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@ -111,8 +112,8 @@ Blocking probes
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thread.
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The IDLE probe in useful to perform dynamic linking, it allows to wait for for
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a safe moment when an unlink/link operation can be done. Since the event is a
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blocking event, it will also make sure that the pad stays idle until the probe
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a safe moment when an unlink/link operation can be done. Since the probe is a
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blocking probe, it will also make sure that the pad stays idle until the probe
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is removed.
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When the BLOCK flag is set, the probe callback will be called when new data
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@ -135,7 +136,7 @@ Non-Blocking probes
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Push dataflow
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-------------
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All probes have the GST_PAD_PROBE_TYPE_PUSH flag set in the callbacks.
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Push probes have the GST_PAD_PROBE_TYPE_PUSH flag set in the callbacks.
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In push based scheduling, the blocking probe is called first with the data item.
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Then the data probes are called before the peer pad chain or event function is
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@ -144,13 +145,13 @@ called.
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The data probes are called before the peer pad is checked. This allows for
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linking the pad in either the BLOCK or DATA probes on the pad.
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Before the peerpad chain or event function is called, the peer pad data probes
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are called.
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Before the peerpad chain or event function is called, the peer pad block and
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data probes are called.
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Finally, the IDLE probe is called on the pad after the data was sent to the
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peer pad.
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The push dataflow probe behavior is the same for buffers and biderectional events.
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The push dataflow probe behavior is the same for buffers and bidirectional events.
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pad peerpad
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@ -191,19 +192,20 @@ The push dataflow probe behavior is the same for buffers and biderectional event
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Pull dataflow
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-------------
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All probes have the GST_PAD_PROBE_TYPE_PULL flag set in the callbacks.
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Pull probes have the GST_PAD_PROBE_TYPE_PULL flag set in the callbacks.
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The gst_pad_pull_range() call will first trigger the BLOCK probes without a DATA
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item. This allows the pad to be linked before the peer pad is resolved.
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item. This allows the pad to be linked before the peer pad is resolved. It also
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allows the callback to set a data item in the probe info.
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After the getrange function is called on the peer pad and there is a data item,
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the DATA probes are called.
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After the blocking probe and the getrange function is called on the peer pad
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and there is a data item, the DATA probes are called.
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When control returns to the sinkpad, the IDLE callbacks are called. The IDLE
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callback is called without a data item so that it will also be called when there
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was an error.
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It there is a valid DATA item, the DATA probes are called for the item.
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If there is a valid DATA item, the DATA probes are called for the item.
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srcpad sinkpad
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84
gst/gstpad.c
84
gst/gstpad.c
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@ -3400,20 +3400,40 @@ no_match:
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}
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}
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#define PROBE_ND_FULL(pad,mask,label,defaultval) \
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#define PROBE_PRE_PULL(pad,mask,data,offs,size,label,probed,defaultval) \
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G_STMT_START { \
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if (G_UNLIKELY (pad->num_probes)) { \
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GstPadProbeInfo info = { mask, NULL }; \
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/* we start with passing NULL as the data item */ \
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GstPadProbeInfo info = { mask, NULL, offs, size }; \
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ret = do_probe_callbacks (pad, &info, defaultval); \
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/* store the possibly updated data item */ \
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data = GST_PAD_PROBE_INFO_DATA (&info); \
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/* if something went wrong, exit */ \
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if (G_UNLIKELY (ret != defaultval && ret != GST_FLOW_OK)) \
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goto label; \
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/* otherwise check if the probe retured data */ \
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if (G_UNLIKELY (data != NULL)) \
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goto probed; \
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} \
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} G_STMT_END
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/* a probe that does not take or return any data */
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#define PROBE_NO_DATA(pad,mask,label,defaultval) \
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G_STMT_START { \
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if (G_UNLIKELY (pad->num_probes)) { \
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/* pass NULL as the data item */ \
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GstPadProbeInfo info = { mask, NULL, 0, 0 }; \
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ret = do_probe_callbacks (pad, &info, defaultval); \
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if (G_UNLIKELY (ret != defaultval && ret != GST_FLOW_OK)) \
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goto label; \
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} \
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} G_STMT_END
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#define PROBE_FULL(pad,mask,data,label,defaultval) \
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#define PROBE_FULL(pad,mask,data,offs,size,label,defaultval) \
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G_STMT_START { \
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if (G_UNLIKELY (pad->num_probes)) { \
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GstPadProbeInfo info = { mask, data }; \
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GstPadProbeInfo info = { mask, data, offs, size }; \
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ret = do_probe_callbacks (pad, &info, defaultval); \
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data = GST_PAD_PROBE_INFO_DATA (&info); \
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if (G_UNLIKELY (ret != defaultval && ret != GST_FLOW_OK)) \
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@ -3421,10 +3441,10 @@ no_match:
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} \
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} G_STMT_END
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#define PROBE(pad,mask,data,label) \
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PROBE_FULL(pad, mask, data, label, GST_FLOW_OK);
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#define PROBE_ND(pad,mask,label) \
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PROBE_ND_FULL(pad, mask, label, GST_FLOW_OK);
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#define PROBE_PUSH(pad,mask,data,label) \
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PROBE_FULL(pad, mask, data, -1, -1, label, GST_FLOW_OK);
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#define PROBE_PULL(pad,mask,data,offs,size,label) \
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PROBE_FULL(pad, mask, data, offs, size, label, GST_FLOW_OK);
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static GstFlowReturn
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do_probe_callbacks (GstPad * pad, GstPadProbeInfo * info,
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@ -3637,9 +3657,9 @@ gst_pad_chain_data_unchecked (GstPad * pad, GstPadProbeType type, void *data)
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goto events_error;
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}
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PROBE (pad, type | GST_PAD_PROBE_TYPE_BLOCK, data, probe_stopped);
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PROBE_PUSH (pad, type | GST_PAD_PROBE_TYPE_BLOCK, data, probe_stopped);
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PROBE (pad, type, data, probe_stopped);
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PROBE_PUSH (pad, type, data, probe_stopped);
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GST_OBJECT_UNLOCK (pad);
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@ -3844,10 +3864,10 @@ gst_pad_push_data (GstPad * pad, GstPadProbeType type, void *data)
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goto flushing;
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/* do block probes */
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PROBE (pad, type | GST_PAD_PROBE_TYPE_BLOCK, data, probe_stopped);
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PROBE_PUSH (pad, type | GST_PAD_PROBE_TYPE_BLOCK, data, probe_stopped);
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/* do post-blocking probes */
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PROBE (pad, type, data, probe_stopped);
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PROBE_PUSH (pad, type, data, probe_stopped);
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if (G_UNLIKELY ((peer = GST_PAD_PEER (pad)) == NULL))
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goto not_linked;
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@ -3865,7 +3885,7 @@ gst_pad_push_data (GstPad * pad, GstPadProbeType type, void *data)
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pad->priv->using--;
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if (pad->priv->using == 0) {
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/* pad is not active anymore, trigger idle callbacks */
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PROBE_ND_FULL (pad, GST_PAD_PROBE_TYPE_PUSH | GST_PAD_PROBE_TYPE_IDLE,
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PROBE_NO_DATA (pad, GST_PAD_PROBE_TYPE_PUSH | GST_PAD_PROBE_TYPE_IDLE,
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probe_stopped, ret);
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}
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GST_OBJECT_UNLOCK (pad);
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@ -3991,8 +4011,10 @@ gst_pad_get_range_unchecked (GstPad * pad, guint64 offset, guint size,
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if (G_UNLIKELY (GST_PAD_IS_FLUSHING (pad)))
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goto flushing;
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PROBE_ND (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BLOCK,
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probe_stopped);
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/* when one of the probes returns a buffer, probed_data will be called and we
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* skip calling the getrange function */
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PROBE_PRE_PULL (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BLOCK,
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*buffer, offset, size, probe_stopped, probed_data, GST_FLOW_OK);
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GST_OBJECT_UNLOCK (pad);
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if (G_UNLIKELY ((getrangefunc = GST_PAD_GETRANGEFUNC (pad)) == NULL))
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@ -4010,8 +4032,9 @@ gst_pad_get_range_unchecked (GstPad * pad, guint64 offset, guint size,
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/* can only fire the signal if we have a valid buffer */
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GST_OBJECT_LOCK (pad);
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PROBE (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BUFFER, *buffer,
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probe_stopped_unref);
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probed_data:
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PROBE_PULL (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BUFFER,
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*buffer, offset, size, probe_stopped_unref);
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GST_OBJECT_UNLOCK (pad);
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GST_PAD_STREAM_UNLOCK (pad);
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@ -4139,8 +4162,10 @@ gst_pad_pull_range (GstPad * pad, guint64 offset, guint size,
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if (G_UNLIKELY (GST_PAD_IS_FLUSHING (pad)))
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goto flushing;
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PROBE_ND (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BLOCK,
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pre_probe_stopped);
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/* when one of the probes returns a buffer, probed_data will be called and we
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* skip calling the peer getrange function */
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PROBE_PRE_PULL (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BLOCK,
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*buffer, offset, size, pre_probe_stopped, probed_data, GST_FLOW_OK);
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if (G_UNLIKELY ((peer = GST_PAD_PEER (pad)) == NULL))
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goto not_linked;
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@ -4157,15 +4182,16 @@ gst_pad_pull_range (GstPad * pad, guint64 offset, guint size,
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pad->priv->using--;
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if (pad->priv->using == 0) {
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/* pad is not active anymore, trigger idle callbacks */
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PROBE_ND (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_IDLE,
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post_probe_stopped);
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PROBE_NO_DATA (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_IDLE,
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post_probe_stopped, ret);
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}
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if (G_UNLIKELY (ret != GST_FLOW_OK))
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goto pull_range_failed;
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PROBE (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BUFFER, buffer,
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post_probe_stopped);
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probed_data:
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PROBE_PULL (pad, GST_PAD_PROBE_TYPE_PULL | GST_PAD_PROBE_TYPE_BUFFER,
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*buffer, offset, size, post_probe_stopped);
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needs_events = GST_PAD_NEEDS_EVENTS (pad);
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if (G_UNLIKELY (needs_events)) {
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@ -4360,7 +4386,7 @@ gst_pad_push_event (GstPad * pad, GstEvent * event)
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if (G_UNLIKELY (GST_PAD_IS_FLUSHING (pad)))
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goto flushed;
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PROBE (pad, type | GST_PAD_PROBE_TYPE_PUSH |
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PROBE_PUSH (pad, type | GST_PAD_PROBE_TYPE_PUSH |
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GST_PAD_PROBE_TYPE_BLOCK, event, probe_stopped);
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break;
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@ -4368,7 +4394,7 @@ gst_pad_push_event (GstPad * pad, GstEvent * event)
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}
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/* send probes after modifying the events above */
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PROBE (pad, type | GST_PAD_PROBE_TYPE_PUSH, event, probe_stopped);
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PROBE_PUSH (pad, type | GST_PAD_PROBE_TYPE_PUSH, event, probe_stopped);
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/* now check the peer pad */
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if (peerpad == NULL)
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@ -4395,8 +4421,8 @@ gst_pad_push_event (GstPad * pad, GstEvent * event)
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pad->priv->using--;
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if (pad->priv->using == 0) {
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/* pad is not active anymore, trigger idle callbacks */
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PROBE_ND (pad, GST_PAD_PROBE_TYPE_PUSH | GST_PAD_PROBE_TYPE_IDLE,
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probe_stopped);
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PROBE_NO_DATA (pad, GST_PAD_PROBE_TYPE_PUSH | GST_PAD_PROBE_TYPE_IDLE,
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probe_stopped, GST_FLOW_OK);
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}
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GST_OBJECT_UNLOCK (pad);
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@ -4574,11 +4600,11 @@ gst_pad_send_event (GstPad * pad, GstEvent * event)
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if (G_UNLIKELY (GST_PAD_IS_FLUSHING (pad)))
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goto flushing;
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PROBE (pad,
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PROBE_PUSH (pad,
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type | GST_PAD_PROBE_TYPE_PUSH |
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GST_PAD_PROBE_TYPE_BLOCK, event, probe_stopped);
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PROBE (pad, type | GST_PAD_PROBE_TYPE_PUSH, event, probe_stopped);
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PROBE_PUSH (pad, type | GST_PAD_PROBE_TYPE_PUSH, event, probe_stopped);
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break;
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}
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27
gst/gstpad.h
27
gst/gstpad.h
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@ -213,9 +213,9 @@ typedef enum {
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/**
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* GstPadActivateMode:
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* @GST_PAD_ACTIVATE_NONE: Pad will not handle dataflow
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* @GST_PAD_ACTIVATE_PUSH: Pad handles dataflow in downstream push mode
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* @GST_PAD_ACTIVATE_PULL: Pad handles dataflow in upstream pull mode
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* @GST_PAD_ACTIVATE_NONE: Pad will not handle dataflow
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* @GST_PAD_ACTIVATE_PUSH: Pad handles dataflow in downstream push mode
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* @GST_PAD_ACTIVATE_PULL: Pad handles dataflow in upstream pull mode
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*
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* The status of a GstPad. After activating a pad, which usually happens when the
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* parent element goes from READY to PAUSED, the GstPadActivateMode defines if the
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@ -531,7 +531,12 @@ typedef enum
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/**
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* GstPadProbeInfo:
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* @type: the current probe type
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* @data: type specific data
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* @data: type specific data, check the @type field to know the datatype.
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* This field can be NULL.
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* @offset: offset of pull probe, this field is valid when @type contains
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* #GST_PAD_PROBE_TYPE_PULL
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* @size: size of pull probe, this field is valid when @type contains
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* #GST_PAD_PROBE_TYPE_PULL
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*
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* Info passed in the #GstPadProbeCallback.
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*/
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@ -539,6 +544,8 @@ typedef struct
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{
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GstPadProbeType type;
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gpointer data;
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guint64 offset;
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guint size;
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} GstPadProbeInfo;
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#define GST_PAD_PROBE_INFO_TYPE(d) ((d)->type)
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@ -548,6 +555,9 @@ typedef struct
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#define GST_PAD_PROBE_INFO_BUFFER_LIST(d) GST_BUFFER_LIST_CAST(GST_PAD_PROBE_INFO_DATA(d))
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#define GST_PAD_PROBE_INFO_EVENT(d) GST_EVENT_CAST(GST_PAD_PROBE_INFO_DATA(d))
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#define GST_PAD_PROBE_INFO_OFFSET(d) ((d)->offset)
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#define GST_PAD_PROBE_INFO_SIZE(d) ((d)->size)
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/**
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* GstPadProbeCallback
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* @pad: the #GstPad that is blocked
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@ -556,9 +566,11 @@ typedef struct
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*
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* Callback used by gst_pad_add_probe(). Gets called to notify about the current
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* blocking type.
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*
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* The callback is allowed to modify the data pointer in @info.
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*/
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typedef GstPadProbeReturn (*GstPadProbeCallback) (GstPad *pad, GstPadProbeInfo *info,
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gpointer user_data);
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typedef GstPadProbeReturn (*GstPadProbeCallback) (GstPad *pad, GstPadProbeInfo *info,
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gpointer user_data);
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/**
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* GstPadStickyEventsForeachFunction:
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@ -570,7 +582,8 @@ typedef GstPadProbeReturn (*GstPadProbeCallback) (GstPad *pad,
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*
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* Returns: GST_FLOW_OK if the iteration should continue
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*/
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typedef GstFlowReturn (*GstPadStickyEventsForeachFunction) (GstPad *pad, GstEvent *event, gpointer user_data);
|
||||
typedef GstFlowReturn (*GstPadStickyEventsForeachFunction) (GstPad *pad, GstEvent *event,
|
||||
gpointer user_data);
|
||||
|
||||
/**
|
||||
* GstPadFlags:
|
||||
|
|
|
|||
Loading…
Reference in a new issue