1 /* GStreamer A-Law to PCM conversion

     2  * Copyright (C) 2000 by Abramo Bagnara <abramo@alsa-project.org>

     3  *

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

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

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

     7  * version 2.1 of the License, or (at your option) any later version.

     8  *

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

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

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

    12  * Library General Public License for more details.

    13  *

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

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

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

    17  * Boston, MA 02111-1307, USA.

    18  */

    19 /**

    20  * SECTION:element-alawdec

    21  *

    22  * This element decodes alaw audio. Alaw coding is also known as G.711.

    23  */

    24 

    25 #ifdef HAVE_CONFIG_H

    26 #include "config.h"

    27 #endif

    28 

    29 #include "alaw-decode.h"

    30 

    31 extern GstStaticPadTemplate alaw_dec_src_factory;

    32 extern GstStaticPadTemplate alaw_dec_sink_factory;

    33 

    34 GST_DEBUG_CATEGORY_STATIC (alaw_dec_debug);

    35 #define GST_CAT_DEFAULT alaw_dec_debug

    36 

    37 static GstStateChangeReturn

    38 gst_alaw_dec_change_state (GstElement * element, GstStateChange transition);

    39 static GstFlowReturn gst_alaw_dec_chain (GstPad * pad, GstBuffer * buffer);

    40 

    41 GST_BOILERPLATE (GstALawDec, gst_alaw_dec, GstElement, GST_TYPE_ELEMENT);

    42 

    43 /* some day we might have defines in gstconfig.h that tell us about the

    44  * desired cpu/memory/binary size trade-offs */

    45 #define GST_ALAW_DEC_USE_TABLE

    46 

    47 #ifdef GST_ALAW_DEC_USE_TABLE

    48 

    49 static const gint alaw_to_s16_table[256] = {

    50   -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,

    51   -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,

    52   -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,

    53   -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,

    54   -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944,

    55   -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136,

    56   -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472,

    57   -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568,

    58   -344, -328, -376, -360, -280, -264, -312, -296,

    59   -472, -456, -504, -488, -408, -392, -440, -424,

    60   -88, -72, -120, -104, -24, -8, -56, -40,

    61   -216, -200, -248, -232, -152, -136, -184, -168,

    62   -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,

    63   -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,

    64   -688, -656, -752, -720, -560, -528, -624, -592,

    65   -944, -912, -1008, -976, -816, -784, -880, -848,

    66   5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736,

    67   7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784,

    68   2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368,

    69   3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392,

    70   22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,

    71   30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,

    72   11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472,

    73   15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,

    74   344, 328, 376, 360, 280, 264, 312, 296,

    75   472, 456, 504, 488, 408, 392, 440, 424,

    76   88, 72, 120, 104, 24, 8, 56, 40,

    77   216, 200, 248, 232, 152, 136, 184, 168,

    78   1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184,

    79   1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696,

    80   688, 656, 752, 720, 560, 528, 624, 592,

    81   944, 912, 1008, 976, 816, 784, 880, 848

    82 };

    83 

    84 static inline gint

    85 alaw_to_s16 (guint8 a_val)

    86 {

    87   return alaw_to_s16_table[a_val];

    88 }

    89 

    90 #else /* GST_ALAW_DEC_USE_TABLE */

    91 

    92 static inline gint

    93 alaw_to_s16 (guint8 a_val)

    94 {

    95   gint t;

    96   gint seg;

    97 

    98   a_val ^= 0x55;

    99   t = a_val & 0x7f;

   100   if (t < 16)

   101     t = (t << 4) + 8;

   102   else {

   103     seg = (t >> 4) & 0x07;

   104     t = ((t & 0x0f) << 4) + 0x108;

   105     t <<= seg - 1;

   106   }

   107   return ((a_val & 0x80) ? t : -t);

   108 }

   109 

   110 #endif /* GST_ALAW_DEC_USE_TABLE */

   111 

   112 static gboolean

   113 gst_alaw_dec_sink_setcaps (GstPad * pad, GstCaps * caps)

   114 {

   115   GstALawDec *alawdec;

   116   GstStructure *structure;

   117   int rate, channels;

   118   gboolean ret;

   119   GstCaps *outcaps;

   120 

   121   alawdec = GST_ALAW_DEC (GST_PAD_PARENT (pad));

   122 

   123   structure = gst_caps_get_structure (caps, 0);

   124 

   125   ret = gst_structure_get_int (structure, "rate", &rate);

   126   ret &= gst_structure_get_int (structure, "channels", &channels);

   127   if (!ret)

   128     return FALSE;

   129 

   130   outcaps = gst_caps_new_simple ("audio/x-raw-int",

   131       "width", G_TYPE_INT, 16,

   132       "depth", G_TYPE_INT, 16,

   133       "endianness", G_TYPE_INT, G_BYTE_ORDER,

   134       "signed", G_TYPE_BOOLEAN, TRUE,

   135       "rate", G_TYPE_INT, rate, "channels", G_TYPE_INT, channels, NULL);

   136 

   137   ret = gst_pad_set_caps (alawdec->srcpad, outcaps);

   138   gst_caps_unref (outcaps);

   139 

   140   if (ret) {

   141     GST_DEBUG_OBJECT (alawdec, "rate=%d, channels=%d", rate, channels);

   142     alawdec->rate = rate;

   143     alawdec->channels = channels;

   144   }

   145   return ret;

   146 }

   147 

   148 static GstCaps *

   149 gst_alaw_dec_getcaps (GstPad * pad)

   150 {

   151   GstALawDec *alawdec;

   152   GstPad *otherpad;

   153   GstCaps *othercaps, *result;

   154   const GstCaps *templ;

   155   gchar *name;

   156   gint i;

   157 

   158   alawdec = GST_ALAW_DEC (GST_PAD_PARENT (pad));

   159 

   160   /* figure out the name of the caps we are going to return */

   161   if (pad == alawdec->srcpad) {

   162     name = "audio/x-raw-int";

   163     otherpad = alawdec->sinkpad;

   164   } else {

   165     name = "audio/x-alaw";

   166     otherpad = alawdec->srcpad;

   167   }

   168   /* get caps from the peer, this can return NULL when there is no peer */

   169   othercaps = gst_pad_peer_get_caps (otherpad);

   170 

   171   /* get the template caps to make sure we return something acceptable */

   172   templ = gst_pad_get_pad_template_caps (pad);

   173 

   174   if (othercaps) {

   175     /* there was a peer */

   176     othercaps = gst_caps_make_writable (othercaps);

   177 

   178     /* go through the caps and remove the fields we don't want */

   179     for (i = 0; i < gst_caps_get_size (othercaps); i++) {

   180       GstStructure *structure;

   181 

   182       structure = gst_caps_get_structure (othercaps, i);

   183 

   184       /* adjust the name */

   185       gst_structure_set_name (structure, name);

   186 

   187       if (pad == alawdec->sinkpad) {

   188         /* remove the fields we don't want */

   189         gst_structure_remove_fields (structure, "width", "depth", "endianness",

   190             "signed", NULL);

   191       } else {

   192         /* add fixed fields */

   193         gst_structure_set (structure, "width", G_TYPE_INT, 16,

   194             "depth", G_TYPE_INT, 16,

   195             "endianness", G_TYPE_INT, G_BYTE_ORDER,

   196             "signed", G_TYPE_BOOLEAN, TRUE, NULL);

   197       }

   198     }

   199     /* filter against the allowed caps of the pad to return our result */

   200     result = gst_caps_intersect (othercaps, templ);

   201     gst_caps_unref (othercaps);

   202   } else {

   203     /* there was no peer, return the template caps */

   204     result = gst_caps_copy (templ);

   205   }

   206 

   207   return result;

   208 }

   209 

   210 static void

   211 gst_alaw_dec_base_init (gpointer klass)

   212 {

   213   GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

   214 

   215   gst_element_class_add_pad_template (element_class,

   216       gst_static_pad_template_get (&alaw_dec_src_factory));

   217   gst_element_class_add_pad_template (element_class,

   218       gst_static_pad_template_get (&alaw_dec_sink_factory));

   219 

   220   gst_element_class_set_details_simple (element_class, "A Law audio decoder",

   221       "Codec/Decoder/Audio", "Convert 8bit A law to 16bit PCM",

   222       "Zaheer Abbas Merali <zaheerabbas at merali dot org>");

   223 

   224   GST_DEBUG_CATEGORY_INIT (alaw_dec_debug, "alawdec", 0, "A Law audio decoder");

   225 }

   226 

   227 static void

   228 gst_alaw_dec_class_init (GstALawDecClass * klass)

   229 {

   230   GstElementClass *element_class = (GstElementClass *) klass;

   231 

   232   element_class->change_state = GST_DEBUG_FUNCPTR (gst_alaw_dec_change_state);

   233 }

   234 

   235 static void

   236 gst_alaw_dec_init (GstALawDec * alawdec, GstALawDecClass * klass)

   237 {

   238   alawdec->sinkpad =

   239       gst_pad_new_from_static_template (&alaw_dec_sink_factory, "sink");

   240   gst_pad_set_setcaps_function (alawdec->sinkpad,

   241       GST_DEBUG_FUNCPTR (gst_alaw_dec_sink_setcaps));

   242   gst_pad_set_getcaps_function (alawdec->sinkpad,

   243       GST_DEBUG_FUNCPTR (gst_alaw_dec_getcaps));

   244   gst_pad_set_chain_function (alawdec->sinkpad,

   245       GST_DEBUG_FUNCPTR (gst_alaw_dec_chain));

   246   gst_element_add_pad (GST_ELEMENT (alawdec), alawdec->sinkpad);

   247 

   248   alawdec->srcpad =

   249       gst_pad_new_from_static_template (&alaw_dec_src_factory, "src");

   250   gst_pad_use_fixed_caps (alawdec->srcpad);

   251   gst_pad_set_getcaps_function (alawdec->srcpad,

   252       GST_DEBUG_FUNCPTR (gst_alaw_dec_getcaps));

   253   gst_element_add_pad (GST_ELEMENT (alawdec), alawdec->srcpad);

   254 }

   255 

   256 static GstFlowReturn

   257 gst_alaw_dec_chain (GstPad * pad, GstBuffer * buffer)

   258 {

   259   GstALawDec *alawdec;

   260   gint16 *linear_data;

   261   guint8 *alaw_data;

   262   guint alaw_size;

   263   GstBuffer *outbuf;

   264   gint i;

   265   GstFlowReturn ret;

   266 

   267   alawdec = GST_ALAW_DEC (GST_PAD_PARENT (pad));

   268 

   269   if (G_UNLIKELY (alawdec->rate == 0))

   270     goto not_negotiated;

   271 

   272   GST_LOG_OBJECT (alawdec, "buffer with ts=%" GST_TIME_FORMAT,

   273       GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)));

   274 

   275   alaw_data = GST_BUFFER_DATA (buffer);

   276   alaw_size = GST_BUFFER_SIZE (buffer);

   277 

   278   ret =

   279       gst_pad_alloc_buffer_and_set_caps (alawdec->srcpad,

   280       GST_BUFFER_OFFSET_NONE, alaw_size * 2, GST_PAD_CAPS (alawdec->srcpad),

   281       &outbuf);

   282   if (ret != GST_FLOW_OK)

   283     goto alloc_failed;

   284 

   285   linear_data = (gint16 *) GST_BUFFER_DATA (outbuf);

   286 

   287   /* copy discont flag */

   288   if (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DISCONT))

   289     GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DISCONT);

   290 

   291   GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (buffer);

   292   GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (buffer);

   293   gst_buffer_set_caps (outbuf, GST_PAD_CAPS (alawdec->srcpad));

   294 

   295   for (i = 0; i < alaw_size; i++) {

   296     linear_data[i] = alaw_to_s16 (alaw_data[i]);

   297   }

   298   gst_buffer_unref (buffer);

   299 

   300   ret = gst_pad_push (alawdec->srcpad, outbuf);

   301 

   302   return ret;

   303 

   304 not_negotiated:

   305   {

   306     gst_buffer_unref (buffer);

   307     GST_WARNING_OBJECT (alawdec, "no input format set: not-negotiated");

   308     return GST_FLOW_NOT_NEGOTIATED;

   309   }

   310 alloc_failed:

   311   {

   312     gst_buffer_unref (buffer);

   313     GST_DEBUG_OBJECT (alawdec, "pad alloc failed, flow: %s",

   314         gst_flow_get_name (ret));

   315     return ret;

   316   }

   317 }

   318 

   319 static GstStateChangeReturn

   320 gst_alaw_dec_change_state (GstElement * element, GstStateChange transition)

   321 {

   322   GstStateChangeReturn ret;

   323   GstALawDec *dec = GST_ALAW_DEC (element);

   324 

   325   switch (transition) {

   326     default:

   327       break;

   328   }

   329 

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

   331   if (ret != GST_STATE_CHANGE_SUCCESS)

   332     return ret;

   333 

   334   switch (transition) {

   335     case GST_STATE_CHANGE_PAUSED_TO_READY:

   336       dec->rate = 0;

   337       dec->channels = 0;

   338       break;

   339     default:

   340       break;

   341   }

   342 

   343   return ret;

   344 }