2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2005 Wim Taymans <wim@fluendo.com>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
21 #ifndef __GST_BASE_TRANSFORM_H__
22 #define __GST_BASE_TRANSFORM_H__
28 #define GST_TYPE_BASE_TRANSFORM (gst_base_transform_get_type())
29 #define GST_BASE_TRANSFORM(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BASE_TRANSFORM,GstBaseTransform))
30 #define GST_BASE_TRANSFORM_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_BASE_TRANSFORM,GstBaseTransformClass))
31 #define GST_BASE_TRANSFORM_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS((obj),GST_TYPE_BASE_TRANSFORM,GstBaseTransformClass))
32 #define GST_IS_BASE_TRANSFORM(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BASE_TRANSFORM))
33 #define GST_IS_BASE_TRANSFORM_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_BASE_TRANSFORM))
34 #define GST_BASE_TRANSFORM_CAST(obj) ((GstBaseTransform *)(obj))
37 * GST_BASE_TRANSFORM_SINK_NAME:
39 * The name of the templates for the sink pad.
41 #define GST_BASE_TRANSFORM_SINK_NAME "sink"
43 * GST_BASE_TRANSFORM_SRC_NAME:
45 * The name of the templates for the source pad.
47 #define GST_BASE_TRANSFORM_SRC_NAME "src"
50 * GST_BASE_TRANSFORM_SRC_PAD:
51 * @obj: base transform instance
53 * Gives the pointer to the source #GstPad object of the element.
55 #define GST_BASE_TRANSFORM_SRC_PAD(obj) (GST_BASE_TRANSFORM_CAST (obj)->srcpad)
58 * GST_BASE_TRANSFORM_SINK_PAD:
59 * @obj: base transform instance
61 * Gives the pointer to the sink #GstPad object of the element.
63 #define GST_BASE_TRANSFORM_SINK_PAD(obj) (GST_BASE_TRANSFORM_CAST (obj)->sinkpad)
66 * GST_BASE_TRANSFORM_FLOW_DROPPED:
68 * A #GstFlowReturn that can be returned from transform and transform_ip to
69 * indicate that no output buffer was generated.
71 #define GST_BASE_TRANSFORM_FLOW_DROPPED GST_FLOW_CUSTOM_SUCCESS
73 typedef struct _GstBaseTransform GstBaseTransform;
74 typedef struct _GstBaseTransformClass GstBaseTransformClass;
75 typedef struct _GstBaseTransformPrivate GstBaseTransformPrivate;
80 * The opaque #GstBaseTransform data structure.
82 struct _GstBaseTransform {
86 /* source and sink pads */
90 /* MT-protected (with STREAM_LOCK) */
91 gboolean have_segment;
93 /* Default submit_input_buffer places the buffer here,
94 * for consumption by the generate_output method: */
95 GstBuffer *queued_buf;
98 GstBaseTransformPrivate *priv;
100 gpointer _gst_reserved[GST_PADDING_LARGE-1];
104 * GstBaseTransformClass:
105 * @parent_class: Element parent class
106 * @passthrough_on_same_caps: If set to %TRUE, passthrough mode will be
107 * automatically enabled if the caps are the same.
108 * Set to %FALSE by default.
109 * @transform_ip_on_passthrough: If set to %TRUE, @transform_ip will be called in
110 * passthrough mode. The passed buffer might not be
111 * writable. When %FALSE, neither @transform nor
112 * @transform_ip will be called in passthrough mode.
113 * Set to %TRUE by default.
114 * @transform_caps: Optional. Given the pad in this direction and the given
115 * caps, what caps are allowed on the other pad in this
117 * @fixate_caps: Optional. Given the pad in this direction and the given
118 * caps, fixate the caps on the other pad. The function takes
119 * ownership of @othercaps and returns a fixated version of
120 * @othercaps. @othercaps is not guaranteed to be writable.
121 * @accept_caps: Optional.
122 * Subclasses can override this method to check if @caps can be
123 * handled by the element. The default implementation might not be
124 * the most optimal way to check this in all cases.
125 * @set_caps: allows the subclass to be notified of the actual caps set.
127 * Handle a requested query. Subclasses that implement this
128 * should must chain up to the parent if they didn't handle the
130 * @decide_allocation: Setup the allocation parameters for allocating output
131 * buffers. The passed in query contains the result of the
132 * downstream allocation query. This function is only called
133 * when not operating in passthrough mode. The default
134 * implementation will remove all memory dependent metadata.
135 * If there is a @filter_meta method implementation, it will
136 * be called for all metadata API in the downstream query,
137 * otherwise the metadata API is removed.
138 * @filter_meta: Return %TRUE if the metadata API should be proposed in the
139 * upstream allocation query. The default implementation is %NULL
140 * and will cause all metadata to be removed.
141 * @propose_allocation: Propose buffer allocation parameters for upstream elements.
142 * This function must be implemented if the element reads or
143 * writes the buffer content. The query that was passed to
144 * the decide_allocation is passed in this method (or %NULL
145 * when the element is in passthrough mode). The default
146 * implementation will pass the query downstream when in
147 * passthrough mode and will copy all the filtered metadata
148 * API in non-passthrough mode.
149 * @transform_size: Optional. Given the size of a buffer in the given direction
150 * with the given caps, calculate the size in bytes of a buffer
151 * on the other pad with the given other caps.
152 * The default implementation uses get_unit_size and keeps
153 * the number of units the same.
154 * @get_unit_size: Required if the transform is not in-place.
155 * get the size in bytes of one unit for the given caps.
157 * Called when the element starts processing.
158 * Allows opening external resources.
160 * Called when the element stops processing.
161 * Allows closing external resources.
162 * @sink_event: Optional.
163 * Event handler on the sink pad. The default implementation
164 * handles the event and forwards it downstream.
165 * @src_event: Optional.
166 * Event handler on the source pad. The default implementation
167 * handles the event and forwards it upstream.
168 * @prepare_output_buffer: Optional.
169 * Subclasses can override this to do their own
170 * allocation of output buffers. Elements that only do
171 * analysis can return a subbuffer or even just
172 * return a reference to the input buffer (if in
173 * passthrough mode). The default implementation will
174 * use the negotiated allocator or bufferpool and
175 * transform_size to allocate an output buffer or it
176 * will return the input buffer in passthrough mode.
177 * @copy_metadata: Optional.
178 * Copy the metadata from the input buffer to the output buffer.
179 * The default implementation will copy the flags, timestamps and
180 * offsets of the buffer.
181 * @transform_meta: Optional. Transform the metadata on the input buffer to the
182 * output buffer. By default this method is %NULL and no
183 * metadata is copied. subclasses can implement this method and
184 * return %TRUE if the metadata is to be copied.
185 * @before_transform: Optional.
186 * This method is called right before the base class will
187 * start processing. Dynamic properties or other delayed
188 * configuration could be performed in this method.
189 * @transform: Required if the element does not operate in-place.
190 * Transforms one incoming buffer to one outgoing buffer.
191 * The function is allowed to change size/timestamp/duration
192 * of the outgoing buffer.
193 * @transform_ip: Required if the element operates in-place.
194 * Transform the incoming buffer in-place.
196 * @submit_input_buffer: Function which accepts a new input buffer and pre-processes it.
197 * The default implementation performs caps (re)negotiation, then
198 * QoS if needed, and places the input buffer into the @queued_buf
199 * member variable. If the buffer is dropped due to QoS, it returns
200 * GST_BASE_TRANSFORM_FLOW_DROPPED. If this input buffer is not
201 * contiguous with any previous input buffer, then @is_discont
202 * is set to #TRUE. (Since: 1.6)
203 * @generate_output: Called after each new input buffer is submitted repeatedly
204 * until it either generates an error or fails to generate an output
205 * buffer. The default implementation takes the contents of the
206 * @queued_buf variable, generates an output buffer if needed
207 * by calling the class @prepare_output_buffer, and then
208 * calls either @transform or @transform_ip. Elements that don't
209 * do 1-to-1 transformations on input to output buffers can either
210 * return GST_BASE_TRANSFORM_FLOW_DROPPED or simply not generate
211 * an output buffer until they are ready to do so. (Since: 1.6)
213 * Subclasses can override any of the available virtual methods or not, as
214 * needed. At minimum either @transform or @transform_ip need to be overridden.
215 * If the element can overwrite the input data with the results (data is of the
216 * same type and quantity) it should provide @transform_ip.
218 struct _GstBaseTransformClass {
219 GstElementClass parent_class;
222 gboolean passthrough_on_same_caps;
223 gboolean transform_ip_on_passthrough;
225 /* virtual methods for subclasses */
226 GstCaps* (*transform_caps) (GstBaseTransform *trans,
227 GstPadDirection direction,
228 GstCaps *caps, GstCaps *filter);
229 GstCaps* (*fixate_caps) (GstBaseTransform *trans,
230 GstPadDirection direction, GstCaps *caps,
232 gboolean (*accept_caps) (GstBaseTransform *trans, GstPadDirection direction,
234 gboolean (*set_caps) (GstBaseTransform *trans, GstCaps *incaps,
236 gboolean (*query) (GstBaseTransform *trans, GstPadDirection direction,
239 /* decide allocation query for output buffers */
240 gboolean (*decide_allocation) (GstBaseTransform *trans, GstQuery *query);
241 gboolean (*filter_meta) (GstBaseTransform *trans, GstQuery *query,
242 GType api, const GstStructure *params);
244 /* propose allocation query parameters for input buffers */
245 gboolean (*propose_allocation) (GstBaseTransform *trans, GstQuery *decide_query,
249 gboolean (*transform_size) (GstBaseTransform *trans,
250 GstPadDirection direction,
251 GstCaps *caps, gsize size,
252 GstCaps *othercaps, gsize *othersize);
254 gboolean (*get_unit_size) (GstBaseTransform *trans, GstCaps *caps,
258 gboolean (*start) (GstBaseTransform *trans);
259 gboolean (*stop) (GstBaseTransform *trans);
261 /* sink and src pad event handlers */
262 gboolean (*sink_event) (GstBaseTransform *trans, GstEvent *event);
263 gboolean (*src_event) (GstBaseTransform *trans, GstEvent *event);
265 GstFlowReturn (*prepare_output_buffer) (GstBaseTransform * trans,
266 GstBuffer *input, GstBuffer **outbuf);
269 gboolean (*copy_metadata) (GstBaseTransform *trans, GstBuffer *input,
271 gboolean (*transform_meta) (GstBaseTransform *trans, GstBuffer *outbuf,
272 GstMeta *meta, GstBuffer *inbuf);
274 void (*before_transform) (GstBaseTransform *trans, GstBuffer *buffer);
277 GstFlowReturn (*transform) (GstBaseTransform *trans, GstBuffer *inbuf,
279 GstFlowReturn (*transform_ip) (GstBaseTransform *trans, GstBuffer *buf);
281 GstFlowReturn (*submit_input_buffer) (GstBaseTransform *trans, gboolean is_discont, GstBuffer *input);
282 GstFlowReturn (*generate_output) (GstBaseTransform *trans, GstBuffer **outbuf);
285 gpointer _gst_reserved[GST_PADDING_LARGE - 2];
288 GType gst_base_transform_get_type (void);
290 void gst_base_transform_set_passthrough (GstBaseTransform *trans,
291 gboolean passthrough);
292 gboolean gst_base_transform_is_passthrough (GstBaseTransform *trans);
294 void gst_base_transform_set_in_place (GstBaseTransform *trans,
296 gboolean gst_base_transform_is_in_place (GstBaseTransform *trans);
298 void gst_base_transform_update_qos (GstBaseTransform *trans,
300 GstClockTimeDiff diff,
301 GstClockTime timestamp);
302 void gst_base_transform_set_qos_enabled (GstBaseTransform *trans,
304 gboolean gst_base_transform_is_qos_enabled (GstBaseTransform *trans);
306 void gst_base_transform_set_gap_aware (GstBaseTransform *trans,
309 void gst_base_transform_set_prefer_passthrough (GstBaseTransform *trans,
310 gboolean prefer_passthrough);
312 GstBufferPool * gst_base_transform_get_buffer_pool (GstBaseTransform *trans);
313 void gst_base_transform_get_allocator (GstBaseTransform *trans,
314 GstAllocator **allocator,
315 GstAllocationParams *params);
317 void gst_base_transform_reconfigure_sink (GstBaseTransform *trans);
318 void gst_base_transform_reconfigure_src (GstBaseTransform *trans);
319 gboolean gst_base_transform_update_src_caps (GstBaseTransform *trans,
320 GstCaps *updated_caps);
323 #endif /* __GST_BASE_TRANSFORM_H__ */