swfdec/swfdec_audio_decoder.c

   1 /* Swfdec
   2  * Copyright (C) 2006-2008 Benjamin Otte <otte@gnome.org>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser 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  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301  USA
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #include "swfdec_audio_decoder.h"
  25 #include "swfdec_debug.h"
  26 #include "swfdec_internal.h"
  27
  28 G_DEFINE_TYPE (SwfdecAudioDecoder, swfdec_audio_decoder, G_TYPE_OBJECT)
  29
  30 static void
  31 swfdec_audio_decoder_do_set_codec_data (SwfdecAudioDecoder *decoder,
  32     SwfdecBuffer *buffer)
  33 {
  34   SWFDEC_WARNING ("%s does not implement codec data",
  35       G_OBJECT_TYPE_NAME (decoder));
  36 }
  37
  38 static void
  39 swfdec_audio_decoder_class_init (SwfdecAudioDecoderClass *klass)
  40 {
  41   klass->set_codec_data = swfdec_audio_decoder_do_set_codec_data;
  42 }
  43
  44 static void
  45 swfdec_audio_decoder_init (SwfdecAudioDecoder *audio_decoder)
  46 {
  47 }
  48
  49 static GSList *audio_codecs = NULL;
  50
  51 void
  52 swfdec_audio_decoder_register (GType type)
  53 {
  54   g_return_if_fail (g_type_is_a (type, SWFDEC_TYPE_AUDIO_DECODER));
  55
  56   audio_codecs = g_slist_append (audio_codecs, GSIZE_TO_POINTER ((gsize) type));
  57 }
  58
  59 gboolean
  60 swfdec_audio_decoder_prepare (guint codec, SwfdecAudioFormat format, char **missing)
  61 {
  62   char *detail = NULL, *s = NULL;
  63   GSList *walk;
  64
  65   for (walk = audio_codecs; walk; walk = walk->next) {
  66     SwfdecAudioDecoderClass *klass = g_type_class_ref (GPOINTER_TO_SIZE (walk->data));
  67     if (klass->prepare (codec, format, &s)) {
  68       g_free (detail);
  69       g_free (s);
  70       if (missing)
  71         *missing = NULL;
  72       g_type_class_unref (klass);
  73       return TRUE;
  74     }
  75     if (s) {
  76       if (detail == NULL)
  77         detail = s;
  78       else
  79         g_free (s);
  80       s = NULL;
  81     }
  82     g_type_class_unref (klass);
  83   }
  84   if (missing)
  85     *missing = detail;
  86   else
  87     g_free (detail);
  88   return FALSE;
  89 }
  90
  91 /**
  92  * swfdec_audio_decoder_new:
  93  * @codec: codec id
  94  * @format: #SwfdecAudioCodec to decode
  95  *
  96  * Creates a decoder suitable for decoding @format. If no decoder is available
  97  * for the given for mat, %NULL is returned.
  98  *
  99  * Returns: a new decoder or %NULL
 100  **/
 101 SwfdecAudioDecoder *
 102 swfdec_audio_decoder_new (guint codec, SwfdecAudioFormat format)
 103 {
 104   SwfdecAudioDecoder *ret = NULL;
 105   GSList *walk;
 106
 107   g_return_val_if_fail (SWFDEC_IS_AUDIO_FORMAT (format), NULL);
 108
 109   for (walk = audio_codecs; walk; walk = walk->next) {
 110     SwfdecAudioDecoderClass *klass = g_type_class_ref (GPOINTER_TO_SIZE (walk->data));
 111     ret = klass->create (codec, format);
 112     g_type_class_unref (klass);
 113     if (ret)
 114       break;
 115   }
 116
 117   if (ret == NULL) {
 118     ret = g_object_new (SWFDEC_TYPE_AUDIO_DECODER, NULL);
 119     swfdec_audio_decoder_error (ret, "no suitable decoder for audio codec %u", codec);
 120   }
 121
 122   ret->codec = codec;
 123   ret->format = format;
 124
 125   return ret;
 126 }
 127
 128 /**
 129  * swfdec_audio_decoder_set_codec_data:
 130  * @decoder: an audio decoder
 131  * @buffer: setup data for the decoder. May be %NULL
 132  *
 133  * Provides setup data for the audio decoder. This function is usually called
 134  * on initialization, but can be called at any time. Currently this
 135  * functionality is only used for AAC audio.
 136  **/
 137 void
 138 swfdec_audio_decoder_set_codec_data (SwfdecAudioDecoder *decoder, SwfdecBuffer *buffer)
 139 {
 140   SwfdecAudioDecoderClass *klass;
 141
 142   g_return_if_fail (SWFDEC_IS_AUDIO_DECODER (decoder));
 143
 144   if (decoder->error)
 145     return;
 146   klass = SWFDEC_AUDIO_DECODER_GET_CLASS (decoder);
 147   klass->set_codec_data (decoder, buffer);
 148 }
 149
 150 /**
 151  * swfdec_audio_decoder_push:
 152  * @decoder: a #SwfdecAudioDecoder
 153  * @buffer: a #SwfdecBuffer to process or %NULL to flush
 154  *
 155  * Pushes a new buffer into the decoding pipeline. After this the results can
 156  * be queried using swfdec_audio_decoder_pull(). Some decoders may not decode
 157  * all available data immediately. So when you are done decoding, you may want
 158  * to flush the decoder. Flushing can be achieved by passing %NULL as the
 159  * @buffer argument. Do this when you are finished decoding.
 160  **/
 161 void
 162 swfdec_audio_decoder_push (SwfdecAudioDecoder *decoder, SwfdecBuffer *buffer)
 163 {
 164   SwfdecAudioDecoderClass *klass;
 165
 166   g_return_if_fail (SWFDEC_IS_AUDIO_DECODER (decoder));
 167
 168   if (decoder->error)
 169     return;
 170   klass = SWFDEC_AUDIO_DECODER_GET_CLASS (decoder);
 171   klass->push (decoder, buffer);
 172 }
 173
 174 /**
 175  * swfdec_audio_decoder_pull:
 176  * @decoder: a #SwfdecAudioDecoder
 177  *
 178  * Gets the next buffer of decoded audio data. Since some decoders do not
 179  * produce one output buffer per input buffer, any number of buffers may be
 180  * available after calling swfdec_audio_decoder_push(), even none. When no more
 181  * buffers are available, this function returns %NULL. You need to provide more
 182  * input in then. A simple decoding pipeline would look like this:
 183  * <informalexample><programlisting>do {
 184  *   input = next_input_buffer ();
 185  *   swfdec_audio_decoder_push (decoder, input);
 186  *   while ((output = swfdec_audio_decoder_pull (decoder))) {
 187  *     ... process output ...
 188  *   }
 189  * } while (input != NULL); </programlisting></informalexample>
 190  *
 191  * Returns: the next buffer or %NULL if no more buffers are available.
 192  **/
 193 SwfdecBuffer *
 194 swfdec_audio_decoder_pull (SwfdecAudioDecoder *decoder)
 195 {
 196   SwfdecAudioDecoderClass *klass;
 197   SwfdecBuffer *result;
 198
 199   g_return_val_if_fail (SWFDEC_IS_AUDIO_DECODER (decoder), NULL);
 200
 201   if (decoder->error)
 202     return NULL;
 203   klass = SWFDEC_AUDIO_DECODER_GET_CLASS (decoder);
 204   result = klass->pull (decoder);
 205   /* result must be n samples of 44.1kHz stereo 16bit - and one sample is 4 bytes */
 206   g_assert (result == NULL || result->length % 4 == 0);
 207   return result;
 208 }
 209
 210 void
 211 swfdec_audio_decoder_error (SwfdecAudioDecoder *decoder, const char *error, ...)
 212 {
 213   va_list args;
 214
 215   g_return_if_fail (SWFDEC_IS_AUDIO_DECODER (decoder));
 216   g_return_if_fail (error != NULL);
 217
 218   va_start (args, error);
 219   swfdec_audio_decoder_errorv (decoder, error, args);
 220   va_end (args);
 221 }
 222
 223 void
 224 swfdec_audio_decoder_errorv (SwfdecAudioDecoder *decoder, const char *error, va_list args)
 225 {
 226   char *real;
 227
 228   g_return_if_fail (SWFDEC_IS_AUDIO_DECODER (decoder));
 229   g_return_if_fail (error != NULL);
 230
 231   real = g_strdup_vprintf (error, args);
 232   SWFDEC_ERROR ("error decoding audio: %s", real);
 233   g_free (real);
 234   decoder->error = TRUE;
 235 }
 236
 237 /**
 238  * swfdec_audio_decoder_uses_format:
 239  * @decoder: the decoder to check
 240  * @codec: the codec the decoder should use
 241  * @format: the format the decoder should use
 242  *
 243  * This is a little helper function that checks if the decoder uses the right
 244  * format.
 245  *
 246  * Returns: %TRUE if the @decoder uses the given @codec and @format, %FALSE
 247  *          otherwise.
 248  **/
 249 gboolean
 250 swfdec_audio_decoder_uses_format (SwfdecAudioDecoder *decoder, guint codec,
 251     SwfdecAudioFormat format)
 252 {
 253   g_return_val_if_fail (SWFDEC_IS_AUDIO_DECODER (decoder), FALSE);
 254   g_return_val_if_fail (SWFDEC_IS_AUDIO_FORMAT (format), FALSE);
 255
 256   return decoder->codec == codec && decoder->format == format;
 257 }
 258