1 /* GStreamer

     2  * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>

     3  *                    2001 Thomas <thomas@apestaart.org>

     4  *               2005,2006 Wim Taymans <wim@fluendo.com>

     5  *

     6  * adder.c: Adder element, N in, one out, samples are added

     7  *

     8  * This library is free software; you can redistribute it and/or

     9  * modify it under the terms of the GNU Library General Public

    10  * License as published by the Free Software Foundation; either

    11  * version 2 of the License, or (at your option) any later version.

    12  *

    13  * This library is distributed in the hope that it will be useful,

    14  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    16  * Library General Public License for more details.

    17  *

    18  * You should have received a copy of the GNU Library General Public

    19  * License along with this library; if not, write to the

    20  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

    21  * Boston, MA 02111-1307, USA.

    22  */

    23 /**

    24  * SECTION:element-adder

    25  *

    26  * <refsect2>

    27  * <para>

    28  * The Adder allows to mix several streams into one by adding the data.

    29  * Mixed data is clamped to the min/max values of the data format.

    30  * </para>

    31  * <title>Example launch line</title>

    32  * <para>

    33  * <programlisting>

    34  * gst-launch audiotestsrc freq=100 ! adder name=mix ! audioconvert ! alsasink audiotestsrc freq=500 ! mix.

    35  * </programlisting>

    36  * This pipeline produces two sine waves mixed together.

    37  * </para>

    38  * <para>

    39  * The Adder currently mixes all data received on the sinkpads as soon as possible

    40  * without trying to synchronize the streams.

    41  * </para>

    42  * </refsect2>

    43  *

    44  * Last reviewed on 2006-05-09 (0.10.7)

    45  */

    46 /* Element-Checklist-Version: 5 */

    47 

    48 #ifdef HAVE_CONFIG_H

    49 #include "config.h"

    50 #endif

    51 #include "gstadder.h"

    52 #include <gst/audio/audio.h>

    53 #include <string.h>             /* strcmp */

    54 

    55 #ifdef __SYMBIAN32__

    56 #include <glib_global.h>

    57 #endif

    58 

    59 /* highest positive/lowest negative x-bit value we can use for clamping */

    60 #define MAX_INT_32  ((gint32) (0x7fffffff))

    61 #define MAX_INT_16  ((gint16) (0x7fff))

    62 #define MAX_INT_8   ((gint8)  (0x7f))

    63 #define MAX_UINT_32 ((guint32)(0xffffffff))

    64 #define MAX_UINT_16 ((guint16)(0xffff))

    65 #define MAX_UINT_8  ((guint8) (0xff))

    66 

    67 #define MIN_INT_32  ((gint32) (0x80000000))

    68 #define MIN_INT_16  ((gint16) (0x8000))

    69 #define MIN_INT_8   ((gint8)  (0x80))

    70 #define MIN_UINT_32 ((guint32)(0x00000000))

    71 #define MIN_UINT_16 ((guint16)(0x0000))

    72 #define MIN_UINT_8  ((guint8) (0x00))

    73 

    74 #define GST_CAT_DEFAULT gst_adder_debug

    75 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

    76 

    77 /* elementfactory information */

    78 static const GstElementDetails adder_details = GST_ELEMENT_DETAILS ("Adder",

    79     "Generic/Audio",

    80     "Add N audio channels together",

    81     "Thomas <thomas@apestaart.org>");

    82 

    83 static GstStaticPadTemplate gst_adder_src_template =

    84     GST_STATIC_PAD_TEMPLATE ("src",

    85     GST_PAD_SRC,

    86     GST_PAD_ALWAYS,

    87     GST_STATIC_CAPS (GST_AUDIO_INT_PAD_TEMPLATE_CAPS "; "

    88         GST_AUDIO_FLOAT_PAD_TEMPLATE_CAPS)

    89     );

    90 

    91 static GstStaticPadTemplate gst_adder_sink_template =

    92     GST_STATIC_PAD_TEMPLATE ("sink%d",

    93     GST_PAD_SINK,

    94     GST_PAD_REQUEST,

    95     GST_STATIC_CAPS (GST_AUDIO_INT_PAD_TEMPLATE_CAPS "; "

    96         GST_AUDIO_FLOAT_PAD_TEMPLATE_CAPS)

    97     );

    98 

    99 static void gst_adder_class_init (GstAdderClass * klass);

   100 static void gst_adder_init (GstAdder * adder);

   101 static void gst_adder_finalize (GObject * object);

   102 

   103 static gboolean gst_adder_setcaps (GstPad * pad, GstCaps * caps);

   104 static gboolean gst_adder_query (GstPad * pad, GstQuery * query);

   105 static gboolean gst_adder_src_event (GstPad * pad, GstEvent * event);

   106 static gboolean gst_adder_sink_event (GstPad * pad, GstEvent * event);

   107 

   108 static GstPad *gst_adder_request_new_pad (GstElement * element,

   109     GstPadTemplate * temp, const gchar * unused);

   110 static void gst_adder_release_pad (GstElement * element, GstPad * pad);

   111 

   112 static GstStateChangeReturn gst_adder_change_state (GstElement * element,

   113     GstStateChange transition);

   114 

   115 static GstFlowReturn gst_adder_collected (GstCollectPads * pads,

   116     gpointer user_data);

   117 

   118 static GstElementClass *parent_class = NULL;

   119 #ifdef __SYMBIAN32__

   120 EXPORT_C

   121 #endif

   122 

   123 

   124 GType

   125 gst_adder_get_type (void)

   126 {

   127   static GType adder_type = 0;

   128 

   129   if (G_UNLIKELY (adder_type == 0)) {

   130     static const GTypeInfo adder_info = {

   131       sizeof (GstAdderClass), NULL, NULL,

   132       (GClassInitFunc) gst_adder_class_init, NULL, NULL,

   133       sizeof (GstAdder), 0,

   134       (GInstanceInitFunc) gst_adder_init,

   135     };

   136 

   137     adder_type = g_type_register_static (GST_TYPE_ELEMENT, "GstAdder",

   138         &adder_info, 0);

   139     GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "adder", 0,

   140         "audio channel mixing element");

   141   }

   142   return adder_type;

   143 }

   144 

   145 /* clipping versions */

   146 #define MAKE_FUNC(name,type,ttype,min,max)                      \

   147 static void name (type *out, type *in, gint bytes) {            \

   148   gint i;                                                       \

   149   for (i = 0; i < bytes / sizeof (type); i++)                   \

   150     out[i] = CLAMP ((ttype)out[i] + (ttype)in[i], min, max);    \

   151 }

   152 

   153 /* non-clipping versions (for float) */

   154 #define MAKE_FUNC_NC(name,type,ttype)                           \

   155 static void name (type *out, type *in, gint bytes) {            \

   156   gint i;                                                       \

   157   for (i = 0; i < bytes / sizeof (type); i++)                   \

   158     out[i] = (ttype)out[i] + (ttype)in[i];                      \

   159 }

   160 

   161 /* *INDENT-OFF* */

   162 MAKE_FUNC (add_int32, gint32, gint64, MIN_INT_32, MAX_INT_32)

   163 MAKE_FUNC (add_int16, gint16, gint32, MIN_INT_16, MAX_INT_16)

   164 MAKE_FUNC (add_int8, gint8, gint16, MIN_INT_8, MAX_INT_8)

   165 MAKE_FUNC (add_uint32, guint32, guint64, MIN_UINT_32, MAX_UINT_32)

   166 MAKE_FUNC (add_uint16, guint16, guint32, MIN_UINT_16, MAX_UINT_16)

   167 MAKE_FUNC (add_uint8, guint8, guint16, MIN_UINT_8, MAX_UINT_8)

   168 MAKE_FUNC_NC (add_float64, gdouble, gdouble)

   169 MAKE_FUNC_NC (add_float32, gfloat, gfloat)

   170 /* *INDENT-ON* */

   171 

   172 /* we can only accept caps that we and downstream can handle. */

   173 static GstCaps *

   174 gst_adder_sink_getcaps (GstPad * pad)

   175 {

   176   GstAdder *adder;

   177   GstCaps *result, *peercaps, *sinkcaps;

   178 

   179   adder = GST_ADDER (GST_PAD_PARENT (pad));

   180 

   181   GST_OBJECT_LOCK (adder);

   182   /* get the downstream possible caps */

   183   peercaps = gst_pad_peer_get_caps (adder->srcpad);

   184   /* get the allowed caps on this sinkpad, we use the fixed caps function so

   185    * that it does not call recursively in this function. */

   186   sinkcaps = gst_pad_get_fixed_caps_func (pad);

   187   if (peercaps) {

   188     /* if the peer has caps, intersect */

   189     GST_DEBUG_OBJECT (adder, "intersecting peer and template caps");

   190     result = gst_caps_intersect (peercaps, sinkcaps);

   191     gst_caps_unref (peercaps);

   192     gst_caps_unref (sinkcaps);

   193   } else {

   194     /* the peer has no caps (or there is no peer), just use the allowed caps

   195      * of this sinkpad. */

   196     GST_DEBUG_OBJECT (adder, "no peer caps, using sinkcaps");

   197     result = sinkcaps;

   198   }

   199   GST_OBJECT_UNLOCK (adder);

   200 

   201   return result;

   202 }

   203 

   204 /* the first caps we receive on any of the sinkpads will define the caps for all

   205  * the other sinkpads because we can only mix streams with the same caps.

   206  * */

   207 static gboolean

   208 gst_adder_setcaps (GstPad * pad, GstCaps * caps)

   209 {

   210   GstAdder *adder;

   211   GList *pads;

   212   GstStructure *structure;

   213   const char *media_type;

   214 

   215   adder = GST_ADDER (GST_PAD_PARENT (pad));

   216 

   217   GST_LOG_OBJECT (adder, "setting caps on pad %p,%s to %" GST_PTR_FORMAT, pad,

   218       GST_PAD_NAME (pad), caps);

   219 

   220   /* FIXME, see if the other pads can accept the format. Also lock the

   221    * format on the other pads to this new format. */

   222   GST_OBJECT_LOCK (adder);

   223   pads = GST_ELEMENT (adder)->pads;

   224   while (pads) {

   225     GstPad *otherpad = GST_PAD (pads->data);

   226 

   227     if (otherpad != pad) {

   228       gst_caps_replace (&GST_PAD_CAPS (otherpad), caps);

   229     }

   230     pads = g_list_next (pads);

   231   }

   232   GST_OBJECT_UNLOCK (adder);

   233 

   234   /* parse caps now */

   235   structure = gst_caps_get_structure (caps, 0);

   236   media_type = gst_structure_get_name (structure);

   237   if (strcmp (media_type, "audio/x-raw-int") == 0) {

   238     GST_DEBUG_OBJECT (adder, "parse_caps sets adder to format int");

   239     adder->format = GST_ADDER_FORMAT_INT;

   240     gst_structure_get_int (structure, "width", &adder->width);

   241     gst_structure_get_int (structure, "depth", &adder->depth);

   242     gst_structure_get_int (structure, "endianness", &adder->endianness);

   243     gst_structure_get_boolean (structure, "signed", &adder->is_signed);

   244 

   245     if (adder->endianness != G_BYTE_ORDER)

   246       goto not_supported;

   247 

   248     switch (adder->width) {

   249       case 8:

   250         adder->func = (adder->is_signed ?

   251             (GstAdderFunction) add_int8 : (GstAdderFunction) add_uint8);

   252         break;

   253       case 16:

   254         adder->func = (adder->is_signed ?

   255             (GstAdderFunction) add_int16 : (GstAdderFunction) add_uint16);

   256         break;

   257       case 32:

   258         adder->func = (adder->is_signed ?

   259             (GstAdderFunction) add_int32 : (GstAdderFunction) add_uint32);

   260         break;

   261       default:

   262         goto not_supported;

   263     }

   264   } else if (strcmp (media_type, "audio/x-raw-float") == 0) {

   265     GST_DEBUG_OBJECT (adder, "parse_caps sets adder to format float");

   266     adder->format = GST_ADDER_FORMAT_FLOAT;

   267     gst_structure_get_int (structure, "width", &adder->width);

   268 

   269     switch (adder->width) {

   270       case 32:

   271         adder->func = (GstAdderFunction) add_float32;

   272         break;

   273       case 64:

   274         adder->func = (GstAdderFunction) add_float64;

   275         break;

   276       default:

   277         goto not_supported;

   278     }

   279   } else {

   280     goto not_supported;

   281   }

   282 

   283   gst_structure_get_int (structure, "channels", &adder->channels);

   284   gst_structure_get_int (structure, "rate", &adder->rate);

   285   /* precalc bps */

   286   adder->bps = (adder->width / 8) * adder->channels;

   287 

   288   return TRUE;

   289 

   290   /* ERRORS */

   291 not_supported:

   292   {

   293     GST_DEBUG_OBJECT (adder, "unsupported format set as caps");

   294     return FALSE;

   295   }

   296 }

   297 

   298 /* FIXME, the duration query should reflect how long you will produce

   299  * data, that is the amount of stream time until you will emit EOS.

   300  *

   301  * For synchronized mixing this is always the max of all the durations

   302  * of upstream since we emit EOS when all of them finished.

   303  *

   304  * We don't do synchronized mixing so this really depends on where the

   305  * streams where punched in and what their relative offsets are against

   306  * eachother which we can get from the first timestamps we see.

   307  *

   308  * When we add a new stream (or remove a stream) the duration might

   309  * also become invalid again and we need to post a new DURATION

   310  * message to notify this fact to the parent.

   311  * For now we take the max of all the upstream elements so the simple

   312  * cases work at least somewhat.

   313  */

   314 static gboolean

   315 gst_adder_query_duration (GstAdder * adder, GstQuery * query)

   316 {

   317   gint64 max;

   318   gboolean res;

   319   GstFormat format;

   320   GstIterator *it;

   321   gboolean done;

   322 

   323   /* parse format */

   324   gst_query_parse_duration (query, &format, NULL);

   325 

   326   max = -1;

   327   res = TRUE;

   328   done = FALSE;

   329 

   330   it = gst_element_iterate_sink_pads (GST_ELEMENT_CAST (adder));

   331   while (!done) {

   332     GstIteratorResult ires;

   333     gpointer item;

   334 

   335     ires = gst_iterator_next (it, &item);

   336     switch (ires) {

   337       case GST_ITERATOR_DONE:

   338         done = TRUE;

   339         break;

   340       case GST_ITERATOR_OK:

   341       {

   342         GstPad *pad = GST_PAD_CAST (item);

   343         gint64 duration;

   344 

   345         /* ask sink peer for duration */

   346         res &= gst_pad_query_peer_duration (pad, &format, &duration);

   347         /* take max from all valid return values */

   348         if (res) {

   349           /* valid unknown length, stop searching */

   350           if (duration == -1) {

   351             max = duration;

   352             done = TRUE;

   353           }

   354           /* else see if bigger than current max */

   355           else if (duration > max)

   356             max = duration;

   357         }

   358         break;

   359       }

   360       case GST_ITERATOR_RESYNC:

   361         max = -1;

   362         res = TRUE;

   363         break;

   364       default:

   365         res = FALSE;

   366         done = TRUE;

   367         break;

   368     }

   369   }

   370   gst_iterator_free (it);

   371 

   372   if (res) {

   373     /* and store the max */

   374     gst_query_set_duration (query, format, max);

   375   }

   376 

   377   return res;

   378 }

   379 

   380 static gboolean

   381 gst_adder_query (GstPad * pad, GstQuery * query)

   382 {

   383   GstAdder *adder = GST_ADDER (gst_pad_get_parent (pad));

   384   gboolean res = FALSE;

   385 

   386   switch (GST_QUERY_TYPE (query)) {

   387     case GST_QUERY_POSITION:

   388     {

   389       GstFormat format;

   390 

   391       gst_query_parse_position (query, &format, NULL);

   392 

   393       switch (format) {

   394         case GST_FORMAT_TIME:

   395           /* FIXME, bring to stream time, might be tricky */

   396           gst_query_set_position (query, format, adder->timestamp);

   397           res = TRUE;

   398           break;

   399         case GST_FORMAT_DEFAULT:

   400           gst_query_set_position (query, format, adder->offset);

   401           res = TRUE;

   402           break;

   403         default:

   404           break;

   405       }

   406       break;

   407     }

   408     case GST_QUERY_DURATION:

   409       res = gst_adder_query_duration (adder, query);

   410       break;

   411     default:

   412       /* FIXME, needs a custom query handler because we have multiple

   413        * sinkpads */

   414       res = gst_pad_query_default (pad, query);

   415       break;

   416   }

   417 

   418   gst_object_unref (adder);

   419   return res;

   420 }

   421 

   422 static gboolean

   423 forward_event_func (GstPad * pad, GValue * ret, GstEvent * event)

   424 {

   425   gst_event_ref (event);

   426   GST_LOG_OBJECT (pad, "About to send event %s", GST_EVENT_TYPE_NAME (event));

   427   if (!gst_pad_push_event (pad, event)) {

   428     g_value_set_boolean (ret, FALSE);

   429     GST_WARNING_OBJECT (pad, "Sending event  %p (%s) failed.",

   430         event, GST_EVENT_TYPE_NAME (event));

   431   } else {

   432     GST_LOG_OBJECT (pad, "Sent event  %p (%s).",

   433         event, GST_EVENT_TYPE_NAME (event));

   434   }

   435   gst_object_unref (pad);

   436   return TRUE;

   437 }

   438 

   439 /* forwards the event to all sinkpads, takes ownership of the

   440  * event

   441  *

   442  * Returns: TRUE if the event could be forwarded on all

   443  * sinkpads.

   444  */

   445 static gboolean

   446 forward_event (GstAdder * adder, GstEvent * event)

   447 {

   448   gboolean ret;

   449   GstIterator *it;

   450   GValue vret = { 0 };

   451 

   452   GST_LOG_OBJECT (adder, "Forwarding event %p (%s)", event,

   453       GST_EVENT_TYPE_NAME (event));

   454 

   455   ret = TRUE;

   456 

   457   g_value_init (&vret, G_TYPE_BOOLEAN);

   458   g_value_set_boolean (&vret, TRUE);

   459   it = gst_element_iterate_sink_pads (GST_ELEMENT_CAST (adder));

   460   gst_iterator_fold (it, (GstIteratorFoldFunction) forward_event_func, &vret,

   461       event);

   462   gst_iterator_free (it);

   463   gst_event_unref (event);

   464 

   465   ret = g_value_get_boolean (&vret);

   466 

   467   return ret;

   468 }

   469 

   470 static gboolean

   471 gst_adder_src_event (GstPad * pad, GstEvent * event)

   472 {

   473   GstAdder *adder;

   474   gboolean result;

   475 

   476   adder = GST_ADDER (gst_pad_get_parent (pad));

   477 

   478   switch (GST_EVENT_TYPE (event)) {

   479     case GST_EVENT_QOS:

   480       /* QoS might be tricky */

   481       result = FALSE;

   482       break;

   483     case GST_EVENT_SEEK:

   484     {

   485       GstSeekFlags flags;

   486       GstSeekType curtype;

   487       gint64 cur;

   488 

   489       /* parse the seek parameters */

   490       gst_event_parse_seek (event, &adder->segment_rate, NULL, &flags, &curtype,

   491           &cur, NULL, NULL);

   492 

   493       /* check if we are flushing */

   494       if (flags & GST_SEEK_FLAG_FLUSH) {

   495         /* make sure we accept nothing anymore and return WRONG_STATE */

   496         gst_collect_pads_set_flushing (adder->collect, TRUE);

   497 

   498         /* flushing seek, start flush downstream, the flush will be done

   499          * when all pads received a FLUSH_STOP. */

   500         gst_pad_push_event (adder->srcpad, gst_event_new_flush_start ());

   501       }

   502 

   503       /* now wait for the collected to be finished and mark a new

   504        * segment */

   505       GST_OBJECT_LOCK (adder->collect);

   506       if (curtype == GST_SEEK_TYPE_SET)

   507         adder->segment_position = cur;

   508       else

   509         adder->segment_position = 0;

   510       adder->segment_pending = TRUE;

   511       GST_OBJECT_UNLOCK (adder->collect);

   512 

   513       result = forward_event (adder, event);

   514       break;

   515     }

   516     case GST_EVENT_NAVIGATION:

   517       /* navigation is rather pointless. */

   518       result = FALSE;

   519       break;

   520     default:

   521       /* just forward the rest for now */

   522       result = forward_event (adder, event);

   523       break;

   524   }

   525   gst_object_unref (adder);

   526 

   527   return result;

   528 }

   529 

   530 static gboolean

   531 gst_adder_sink_event (GstPad * pad, GstEvent * event)

   532 {

   533   GstAdder *adder;

   534   gboolean ret;

   535 

   536   adder = GST_ADDER (gst_pad_get_parent (pad));

   537 

   538   GST_DEBUG ("Got %s event on pad %s:%s", GST_EVENT_TYPE_NAME (event),

   539       GST_DEBUG_PAD_NAME (pad));

   540 

   541   switch (GST_EVENT_TYPE (event)) {

   542     case GST_EVENT_FLUSH_STOP:

   543       /* mark a pending new segment. This event is synchronized

   544        * with the streaming thread so we can safely update the

   545        * variable without races. It's somewhat weird because we

   546        * assume the collectpads forwarded the FLUSH_STOP past us

   547        * and downstream (using our source pad, the bastard!).

   548        */

   549       adder->segment_pending = TRUE;

   550       break;

   551     default:

   552       break;

   553   }

   554 

   555   /* now GstCollectPads can take care of the rest, e.g. EOS */

   556   ret = adder->collect_event (pad, event);

   557 

   558   gst_object_unref (adder);

   559   return ret;

   560 }

   561 

   562 static void

   563 gst_adder_class_init (GstAdderClass * klass)

   564 {

   565   GObjectClass *gobject_class;

   566   GstElementClass *gstelement_class;

   567 

   568   gobject_class = (GObjectClass *) klass;

   569 

   570   gobject_class->finalize = gst_adder_finalize;

   571 

   572   gstelement_class = (GstElementClass *) klass;

   573 

   574   gst_element_class_add_pad_template (gstelement_class,

   575       gst_static_pad_template_get (&gst_adder_src_template));

   576   gst_element_class_add_pad_template (gstelement_class,

   577       gst_static_pad_template_get (&gst_adder_sink_template));

   578   gst_element_class_set_details (gstelement_class, &adder_details);

   579 

   580   parent_class = g_type_class_peek_parent (klass);

   581 

   582   gstelement_class->request_new_pad = gst_adder_request_new_pad;

   583   gstelement_class->release_pad = gst_adder_release_pad;

   584   gstelement_class->change_state = gst_adder_change_state;

   585 }

   586 

   587 static void

   588 gst_adder_init (GstAdder * adder)

   589 {

   590   GstPadTemplate *template;

   591 

   592   template = gst_static_pad_template_get (&gst_adder_src_template);

   593   adder->srcpad = gst_pad_new_from_template (template, "src");

   594   gst_object_unref (template);

   595   gst_pad_set_getcaps_function (adder->srcpad,

   596       GST_DEBUG_FUNCPTR (gst_pad_proxy_getcaps));

   597   gst_pad_set_setcaps_function (adder->srcpad,

   598       GST_DEBUG_FUNCPTR (gst_adder_setcaps));

   599   gst_pad_set_query_function (adder->srcpad,

   600       GST_DEBUG_FUNCPTR (gst_adder_query));

   601   gst_pad_set_event_function (adder->srcpad,

   602       GST_DEBUG_FUNCPTR (gst_adder_src_event));

   603   gst_element_add_pad (GST_ELEMENT (adder), adder->srcpad);

   604 

   605   adder->format = GST_ADDER_FORMAT_UNSET;

   606   adder->padcount = 0;

   607   adder->func = NULL;

   608 

   609   /* keep track of the sinkpads requested */

   610   adder->collect = gst_collect_pads_new ();

   611   gst_collect_pads_set_function (adder->collect,

   612       GST_DEBUG_FUNCPTR (gst_adder_collected), adder);

   613 }

   614 

   615 static void

   616 gst_adder_finalize (GObject * object)

   617 {

   618   GstAdder *adder = GST_ADDER (object);

   619 

   620   gst_object_unref (adder->collect);

   621   adder->collect = NULL;

   622 

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

   624 }

   625 

   626 static GstPad *

   627 gst_adder_request_new_pad (GstElement * element, GstPadTemplate * templ,

   628     const gchar * unused)

   629 {

   630   gchar *name;

   631   GstAdder *adder;

   632   GstPad *newpad;

   633   gint padcount;

   634 

   635   if (templ->direction != GST_PAD_SINK)

   636     goto not_sink;

   637 

   638   adder = GST_ADDER (element);

   639 

   640   /* increment pad counter */

   641   padcount = g_atomic_int_exchange_and_add (&adder->padcount, 1);

   642 

   643   name = g_strdup_printf ("sink%d", padcount);

   644   newpad = gst_pad_new_from_template (templ, name);

   645   GST_DEBUG_OBJECT (adder, "request new pad %s", name);

   646   g_free (name);

   647 

   648   gst_pad_set_getcaps_function (newpad,

   649       GST_DEBUG_FUNCPTR (gst_adder_sink_getcaps));

   650   gst_pad_set_setcaps_function (newpad, GST_DEBUG_FUNCPTR (gst_adder_setcaps));

   651   gst_collect_pads_add_pad (adder->collect, newpad, sizeof (GstCollectData));

   652 

   653   /* FIXME: hacked way to override/extend the event function of

   654    * GstCollectPads; because it sets its own event function giving the

   655    * element no access to events */

   656   adder->collect_event = (GstPadEventFunction) GST_PAD_EVENTFUNC (newpad);

   657   gst_pad_set_event_function (newpad, GST_DEBUG_FUNCPTR (gst_adder_sink_event));

   658 

   659   /* takes ownership of the pad */

   660   if (!gst_element_add_pad (GST_ELEMENT (adder), newpad))

   661     goto could_not_add;

   662 

   663   return newpad;

   664 

   665   /* errors */

   666 not_sink:

   667   {

   668     g_warning ("gstadder: request new pad that is not a SINK pad\n");

   669     return NULL;

   670   }

   671 could_not_add:

   672   {

   673     GST_DEBUG_OBJECT (adder, "could not add pad");

   674     gst_collect_pads_remove_pad (adder->collect, newpad);

   675     gst_object_unref (newpad);

   676     return NULL;

   677   }

   678 }

   679 

   680 static void

   681 gst_adder_release_pad (GstElement * element, GstPad * pad)

   682 {

   683   GstAdder *adder;

   684 

   685   adder = GST_ADDER (element);

   686 

   687   GST_DEBUG_OBJECT (adder, "release pad %s:%s", GST_DEBUG_PAD_NAME (pad));

   688 

   689   gst_collect_pads_remove_pad (adder->collect, pad);

   690   gst_element_remove_pad (element, pad);

   691 }

   692 

   693 static GstFlowReturn

   694 gst_adder_collected (GstCollectPads * pads, gpointer user_data)

   695 {

   696   /*

   697    * combine channels by adding sample values

   698    * basic algorithm :

   699    * - this function is called when all pads have a buffer

   700    * - get available bytes on all pads.

   701    * - repeat for each input pad :

   702    *   - read available bytes, copy or add to target buffer

   703    *   - if there's an EOS event, remove the input channel

   704    * - push out the output buffer

   705    */

   706   GstAdder *adder;

   707   guint size;

   708   GSList *collected;

   709   GstBuffer *outbuf;

   710   GstFlowReturn ret;

   711   gpointer outbytes;

   712   gboolean empty = TRUE;

   713 

   714   adder = GST_ADDER (user_data);

   715 

   716   /* this is fatal */

   717   if (G_UNLIKELY (adder->func == NULL))

   718     goto not_negotiated;

   719 

   720   /* get available bytes for reading, this can be 0 which could mean

   721    * empty buffers or EOS, which we will catch when we loop over the

   722    * pads. */

   723   size = gst_collect_pads_available (pads);

   724 

   725   GST_LOG_OBJECT (adder,

   726       "starting to cycle through channels, %d bytes available (bps = %d)", size,

   727       adder->bps);

   728 

   729   outbuf = NULL;

   730   outbytes = NULL;

   731 

   732   for (collected = pads->data; collected; collected = g_slist_next (collected)) {

   733     GstCollectData *data;

   734     guint8 *bytes;

   735     guint len;

   736     GstBuffer *inbuf;

   737 

   738     data = (GstCollectData *) collected->data;

   739 

   740     /* get a subbuffer of size bytes */

   741     inbuf = gst_collect_pads_take_buffer (pads, data, size);

   742     /* NULL means EOS or an empty buffer so we still need to flush in

   743      * case of an empty buffer. */

   744     if (inbuf == NULL) {

   745       GST_LOG_OBJECT (adder, "channel %p: no bytes available", data);

   746       goto next;

   747     }

   748 

   749     bytes = GST_BUFFER_DATA (inbuf);

   750     len = GST_BUFFER_SIZE (inbuf);

   751 

   752     if (outbuf == NULL) {

   753       GST_LOG_OBJECT (adder, "channel %p: making output buffer of %d bytes",

   754           data, size);

   755 

   756       /* first buffer, alloc size bytes. FIXME, we can easily subbuffer

   757        * and _make_writable. */

   758       outbuf = gst_buffer_new_and_alloc (size);

   759       outbytes = GST_BUFFER_DATA (outbuf);

   760       gst_buffer_set_caps (outbuf, GST_PAD_CAPS (adder->srcpad));

   761 

   762       if (!GST_BUFFER_FLAG_IS_SET (inbuf, GST_BUFFER_FLAG_GAP)) {

   763         /* clear if we are only going to fill a partial buffer */

   764         if (G_UNLIKELY (size > len))

   765           memset (outbytes, 0, size);

   766 

   767         GST_LOG_OBJECT (adder, "channel %p: copying %d bytes from data %p",

   768             data, len, bytes);

   769 

   770         /* and copy the data into it */

   771         memcpy (outbytes, bytes, len);

   772         empty = FALSE;

   773       } else {

   774         GST_LOG_OBJECT (adder, "channel %p: zeroing %d bytes from data %p",

   775             data, len, bytes);

   776         memset (outbytes, 0, size);

   777       }

   778     } else {

   779       if (!GST_BUFFER_FLAG_IS_SET (inbuf, GST_BUFFER_FLAG_GAP)) {

   780         GST_LOG_OBJECT (adder, "channel %p: mixing %d bytes from data %p",

   781             data, len, bytes);

   782         /* other buffers, need to add them */

   783         adder->func ((gpointer) outbytes, (gpointer) bytes, len);

   784         empty = FALSE;

   785       } else {

   786         GST_LOG_OBJECT (adder, "channel %p: skipping %d bytes from data %p",

   787             data, len, bytes);

   788       }

   789     }

   790   next:

   791     if (inbuf)

   792       gst_buffer_unref (inbuf);

   793   }

   794 

   795   /* can only happen when no pads to collect or all EOS */

   796   if (outbuf == NULL)

   797     goto eos;

   798 

   799   /* our timestamping is very simple, just an ever incrementing

   800    * counter, the new segment time will take care of their respective

   801    * stream time. */

   802   if (adder->segment_pending) {

   803     GstEvent *event;

   804 

   805     /* FIXME, use rate/applied_rate as set on all sinkpads.

   806      * - currently we just set rate as received from last seek-event

   807      * We could potentially figure out the duration as well using

   808      * the current segment positions and the stated stop positions.

   809      * Also we just start from stream time 0 which is rather

   810      * weird. For non-synchronized mixing, the time should be

   811      * the min of the stream times of all received segments,

   812      * rationale being that the duration is at least going to

   813      * be as long as the earliest stream we start mixing. This

   814      * would also be correct for synchronized mixing but then

   815      * the later streams would be delayed until the stream times

   816      * match.

   817      */

   818     event = gst_event_new_new_segment_full (FALSE, adder->segment_rate,

   819         1.0, GST_FORMAT_TIME, adder->timestamp, -1, adder->segment_position);

   820 

   821     gst_pad_push_event (adder->srcpad, event);

   822     adder->segment_pending = FALSE;

   823     adder->segment_position = 0;

   824   }

   825 

   826   /* set timestamps on the output buffer */

   827   GST_BUFFER_TIMESTAMP (outbuf) = adder->timestamp;

   828   GST_BUFFER_OFFSET (outbuf) = adder->offset;

   829 

   830   /* for the next timestamp, use the sample counter, which will

   831    * never accumulate rounding errors */

   832   adder->offset += size / adder->bps;

   833   adder->timestamp = gst_util_uint64_scale_int (adder->offset,

   834       GST_SECOND, adder->rate);

   835 

   836   /* now we can set the duration of the buffer */

   837   GST_BUFFER_DURATION (outbuf) = adder->timestamp -

   838       GST_BUFFER_TIMESTAMP (outbuf);

   839 

   840   /* if we only processed silence, mark output again as silence */

   841   if (empty)

   842     GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_GAP);

   843 

   844   /* send it out */

   845   GST_LOG_OBJECT (adder, "pushing outbuf, timestamp %" GST_TIME_FORMAT,

   846       GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (outbuf)));

   847   ret = gst_pad_push (adder->srcpad, outbuf);

   848 

   849   return ret;

   850 

   851   /* ERRORS */

   852 not_negotiated:

   853   {

   854     GST_ELEMENT_ERROR (adder, STREAM, FORMAT, (NULL),

   855         ("Unknown data received, not negotiated"));

   856     return GST_FLOW_NOT_NEGOTIATED;

   857   }

   858 eos:

   859   {

   860     GST_DEBUG_OBJECT (adder, "no data available, must be EOS");

   861     gst_pad_push_event (adder->srcpad, gst_event_new_eos ());

   862     return GST_FLOW_UNEXPECTED;

   863   }

   864 }

   865 

   866 static GstStateChangeReturn

   867 gst_adder_change_state (GstElement * element, GstStateChange transition)

   868 {

   869   GstAdder *adder;

   870   GstStateChangeReturn ret;

   871 

   872   adder = GST_ADDER (element);

   873 

   874   switch (transition) {

   875     case GST_STATE_CHANGE_NULL_TO_READY:

   876       break;

   877     case GST_STATE_CHANGE_READY_TO_PAUSED:

   878       adder->timestamp = 0;

   879       adder->offset = 0;

   880       adder->segment_pending = TRUE;

   881       adder->segment_position = 0;

   882       adder->segment_rate = 1.0;

   883       gst_segment_init (&adder->segment, GST_FORMAT_UNDEFINED);

   884       gst_collect_pads_start (adder->collect);

   885       break;

   886     case GST_STATE_CHANGE_PAUSED_TO_PLAYING:

   887       break;

   888     case GST_STATE_CHANGE_PAUSED_TO_READY:

   889       /* need to unblock the collectpads before calling the

   890        * parent change_state so that streaming can finish */

   891       gst_collect_pads_stop (adder->collect);

   892       break;

   893     default:

   894       break;

   895   }

   896 

   897   ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);

   898 

   899   switch (transition) {

   900     default:

   901       break;

   902   }

   903 

   904   return ret;

   905 }

   906 

   907 

   908 static gboolean

   909 plugin_init (GstPlugin * plugin)

   910 {

   911   if (!gst_element_register (plugin, "adder", GST_RANK_NONE, GST_TYPE_ADDER)) {

   912     return FALSE;

   913   }

   914 

   915   return TRUE;

   916 }

   917 

   918 GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,

   919     GST_VERSION_MINOR,

   920     "adder",

   921     "Adds multiple streams",

   922     plugin_init, VERSION, "LGPL", GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN);

   923    

   924 #ifdef __SYMBIAN32__

   925 EXPORT_C 

   926 #endif

   927 GstPluginDesc* _GST_PLUGIN_DESC()

   928 {

   929 	return &gst_plugin_desc;

   930 }