gstreamer/ext/mad/gstmad.c

/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <gst/gst.h>

#include <string.h>
#include <mad.h>

#define GST_TYPE_MAD \
  (gst_mad_get_type())
#define GST_MAD(obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_MAD,GstMad))
#define GST_MAD_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_MAD,GstMad))
#define GST_IS_MAD(obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_MAD))
#define GST_IS_MAD_CLASS(obj) \
  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_MAD))

typedef struct _GstMad GstMad;
typedef struct _GstMadClass GstMadClass;

struct _GstMad {
  GstElement element;

  /* pads */
  GstPad *sinkpad,*srcpad;

  /* state */
  struct mad_stream stream;
  struct mad_frame frame;
  struct mad_synth synth;
  guchar *tempbuffer;
  glong tempsize;
  gboolean need_sync;
  guint64 last_time;
  guint64 framestamp;	/* timestamp-like, but counted in frames */
  guint64 sync_point; 
  guint64 total_samples; /* the number of samples since the sync point */

  gint64 seek_point;

  /* info */
  struct mad_header header;
  gboolean new_header;
  gboolean can_seek;
  gint channels;
  guint framecount;
  gint vbr_average; /* average bitrate */
  gulong vbr_rate; /* average * framecount */

  /* caps */
  gboolean caps_set;
};

struct _GstMadClass {
  GstElementClass parent_class;
};

/* elementfactory information */
static GstElementDetails gst_mad_details = {
  "mad mp3 decoder",
  "Codec/Audio/Decoder",
  "Uses mad code to decode mp3 streams",
  VERSION,
  "Wim Taymans <wim.taymans@chello.be>",
  "(C) 2001",
};


/* Mad signals and args */
enum {
  /* FILL ME */
  LAST_SIGNAL
};

enum {
  ARG_0,
  ARG_LAYER,
  ARG_MODE,
  ARG_EMPHASIS,
  ARG_BITRATE,
  ARG_SAMPLERATE,
  ARG_CHANNELS,
  ARG_AVERAGE_BITRATE,
  /* FILL ME */
};

GST_PAD_TEMPLATE_FACTORY (mad_src_template_factory,
  "src",
  GST_PAD_SRC,
  GST_PAD_ALWAYS,
  GST_CAPS_NEW (
    "mad_src",
    "audio/raw",
      "format",   GST_PROPS_STRING ("int"),
      "law",         GST_PROPS_INT (0),
      "endianness",  GST_PROPS_INT (G_BYTE_ORDER),
      "signed",      GST_PROPS_BOOLEAN (TRUE),
      "width",       GST_PROPS_INT (16),
      "depth",       GST_PROPS_INT (16),
      "rate",        GST_PROPS_INT_RANGE (11025, 48000),
      "channels",    GST_PROPS_INT_RANGE (1, 2)
  )
)

GST_PAD_TEMPLATE_FACTORY (mad_sink_template_factory,
  "sink",
  GST_PAD_SINK,
  GST_PAD_ALWAYS,
  GST_CAPS_NEW (
    "mad_sink",
    "audio/mp3",
    NULL
  )
)


static void 		gst_mad_class_init	(GstMadClass *klass);
static void 		gst_mad_init		(GstMad *mad);
static void 		gst_mad_dispose 	(GObject *object);

static void		gst_mad_set_property	(GObject *object, guint prop_id, 
						 const GValue *value, GParamSpec *pspec);
static void		gst_mad_get_property	(GObject *object, guint prop_id, 
						 GValue *value, GParamSpec *pspec);

static gboolean 	gst_mad_src_event 	(GstPad *pad, GstEvent *event);

static void 		gst_mad_chain 		(GstPad *pad, GstBuffer *buffer);

static GstElementStateReturn
			gst_mad_change_state (GstElement *element);


static GstElementClass *parent_class = NULL;
/* static guint gst_mad_signals[LAST_SIGNAL] = { 0 }; */

GType
gst_mad_get_type (void)
{
  static GType mad_type = 0;

  if (!mad_type) {
    static const GTypeInfo mad_info = {
      sizeof(GstMadClass),      NULL,
      NULL,
      (GClassInitFunc)gst_mad_class_init,
      NULL,
      NULL,
      sizeof(GstMad),
      0,
      (GInstanceInitFunc)gst_mad_init,
    };
    mad_type = g_type_register_static(GST_TYPE_ELEMENT, "GstMad", &mad_info, 0);
  }
  return mad_type;
}

static gchar *layers[]   = { "unknown", "I", "II", "III" };
static gchar *modes[]    = { "single channel", "dual channel", "joint stereo", "stereo" };
static gchar *emphases[] = { "none", "50/15 microseconds", "CCITT J.17" };

static void
gst_mad_class_init (GstMadClass *klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass*) klass;
  gstelement_class = (GstElementClass*) klass;

  parent_class = g_type_class_ref(GST_TYPE_ELEMENT);

  gobject_class->set_property = gst_mad_set_property;
  gobject_class->get_property = gst_mad_get_property;
  gobject_class->dispose = gst_mad_dispose;

  gstelement_class->change_state = gst_mad_change_state;
  
  /* init properties */
  /* currently, string representations are used, we might want to change that */
  /* FIXME: descriptions need to be more technical, default values and ranges need to be selected right */
  g_object_class_install_property (gobject_class, ARG_LAYER,
    g_param_spec_string ("layer", "Layer", "The audio MPEG Layer this stream is encoded in",
			 layers[0], G_PARAM_READABLE));
  g_object_class_install_property (gobject_class, ARG_MODE,
    g_param_spec_string ("mode", "Mode", "The current mode of the channels",
			 modes[0], G_PARAM_READABLE));
  g_object_class_install_property (gobject_class, ARG_EMPHASIS,
    g_param_spec_string ("emphasis", "Emphasis", "Emphasis",
			 emphases[0], G_PARAM_READABLE));
  g_object_class_install_property (gobject_class, ARG_BITRATE,
    g_param_spec_int ("bitrate", "Bitrate", "current bitrate of the stream",
                       0, G_MAXINT, 0, G_PARAM_READABLE));
  g_object_class_install_property (gobject_class, ARG_AVERAGE_BITRATE,
    g_param_spec_int ("average-bitrate", "average bitrate", "average bitrate of the stream",
                       0, G_MAXINT, 0, G_PARAM_READABLE));
  g_object_class_install_property (gobject_class, ARG_SAMPLERATE,
    g_param_spec_int ("samplerate", "Samplerate", "current samplerate of the stream",
                       0, G_MAXINT, 0, G_PARAM_READABLE));
  g_object_class_install_property (gobject_class, ARG_CHANNELS,
    g_param_spec_int ("channels", "Channels", "number of channels",
                       1, 2, 1, G_PARAM_READABLE));
  
}

static void
gst_mad_init (GstMad *mad)
{
  /* create the sink and src pads */
  mad->sinkpad = gst_pad_new_from_template(
		  GST_PAD_TEMPLATE_GET (mad_sink_template_factory), "sink");
  gst_element_add_pad(GST_ELEMENT(mad),mad->sinkpad);
  gst_pad_set_chain_function (mad->sinkpad, GST_DEBUG_FUNCPTR(gst_mad_chain));

  mad->srcpad = gst_pad_new_from_template(
		  GST_PAD_TEMPLATE_GET (mad_src_template_factory), "src");
  gst_element_add_pad(GST_ELEMENT(mad),mad->srcpad);
  gst_pad_set_event_function (mad->srcpad, GST_DEBUG_FUNCPTR(gst_mad_src_event));

  mad->tempbuffer = g_malloc (MAD_BUFFER_MDLEN * 3);
  mad->tempsize = 0;
  mad->need_sync = TRUE;
  mad->last_time = 0;
  mad->framestamp = 0;
  mad->total_samples = 0;
  mad->sync_point = 0;
  mad->new_header = TRUE;
  mad->framecount = 0;
  mad->vbr_average = 0;
  mad->vbr_rate = 0;
}

static void
gst_mad_dispose (GObject *object)
{
  GstMad *mad = GST_MAD (object);

  G_OBJECT_CLASS (parent_class)->dispose (object);

  g_free (mad->tempbuffer);
}

static gboolean
gst_mad_src_event (GstPad *pad, GstEvent *event)
{
  gboolean res = TRUE;
  GstMad *mad;
	    
  mad = GST_MAD (gst_pad_get_parent (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_SEEK:
      if (mad->can_seek) {
	mad->seek_point = GST_EVENT_SEEK_OFFSET (event);
      }
      else {
	res = FALSE;
      }
      break;
    default:
      break;
  }

  return res;
}

static inline signed int 
scale (mad_fixed_t sample)
{
  /* round */
  sample += (1L << (MAD_F_FRACBITS - 16));

  /* clip */
  if (sample >= MAD_F_ONE)
    sample = MAD_F_ONE - 1;
  else if (sample < -MAD_F_ONE)
    sample = -MAD_F_ONE;

  /* quantize */
  return sample >> (MAD_F_FRACBITS + 1 - 16);
}

/* do we need this function? */
static void
gst_mad_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
{
  GstMad *mad;
	    
  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_MAD (object));
	      
  mad = GST_MAD (object);

  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}
static void
gst_mad_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
  GstMad *mad;
	    
  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_MAD (object));
	      
  mad = GST_MAD (object);

  switch (prop_id) {
    case ARG_LAYER:
      g_value_set_string (value, layers[mad->header.layer]);
      break;
    case ARG_MODE:
      g_value_set_string (value, modes[mad->header.mode]);
      break;
    case ARG_EMPHASIS:
      g_value_set_string (value, emphases[mad->header.emphasis]);
      break;
    case ARG_BITRATE:
      g_value_set_int (value, mad->header.bitrate);
      break;
    case ARG_AVERAGE_BITRATE:
      g_value_set_int (value, mad->vbr_average);
      break;
    case ARG_SAMPLERATE:
      g_value_set_int (value, mad->header.samplerate);
      break;
    case ARG_CHANNELS:
      g_value_set_int (value, mad->channels);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}
static void
gst_mad_update_info (GstMad *mad, struct mad_header const *header)
{
  gint abr = mad->vbr_average;
#define CHECK_HEADER(h1,str) 				\
G_STMT_START{							\
  if (mad->header.h1 != header->h1 || mad->new_header) {	\
    mad->header.h1 = header->h1;				\
    g_object_notify (G_OBJECT (mad), str);			\
  };								\
} G_STMT_END
  
  g_object_freeze_notify (G_OBJECT (mad));

  /* update average bitrate */
  if (mad->new_header)
  {
    mad->framecount = 1;
    mad->vbr_rate = header->bitrate;
    abr = 0;
  } else {
    mad->framecount++;
    mad->vbr_rate += header->bitrate;
  }
  mad->vbr_average = (gint) (mad->vbr_rate / mad->framecount);
  if (abr != mad->vbr_average)
  {
    g_object_notify (G_OBJECT (mad), "average_bitrate");
  }

  CHECK_HEADER (layer, 	    "layer");
  CHECK_HEADER (mode, 	    "mode");
  CHECK_HEADER (emphasis,   "emphasis");
  CHECK_HEADER (bitrate,    "bitrate");
  CHECK_HEADER (samplerate, "samplerate");
  if (mad->channels != MAD_NCHANNELS (header) || mad->new_header) {
    mad->channels = MAD_NCHANNELS (header);
    g_object_notify (G_OBJECT (mad), "channels");
  }
  mad->new_header = FALSE;
  
  g_object_thaw_notify (G_OBJECT (mad));
  
#undef CHECK_HEADER
}

static void
gst_mad_chain (GstPad *pad, GstBuffer *buffer)
{
  GstMad *mad;
  gchar *data;
  glong size;

  mad = GST_MAD (gst_pad_get_parent (pad));

  /* end of new bit */
  data = GST_BUFFER_DATA (buffer);
  size = GST_BUFFER_SIZE (buffer);

  if (!GST_PAD_IS_CONNECTED (mad->srcpad)) {
    gst_buffer_unref (buffer);
    return;
  }
  if (mad->sync_point == 0 && GST_BUFFER_TIMESTAMP (buffer) != -1) {
    mad->sync_point = GST_BUFFER_TIMESTAMP (buffer);
    mad->total_samples = 0;
  }

  while (size > 0) {
    gint tocopy;
    guchar *mad_input_buffer;

    /* cut the buffer in MDLEN pieces */
    tocopy = MIN (MAD_BUFFER_MDLEN, size);
	  
    memcpy (mad->tempbuffer + mad->tempsize, data, tocopy);
    mad->tempsize += tocopy;

    size -= tocopy;
    data += tocopy;

    mad_input_buffer = mad->tempbuffer;

    /* if we have data we can try to proceed */
    while (mad->tempsize >= 0) {
      gint consumed;
      guint nchannels, nsamples;
      mad_fixed_t const *left_ch, *right_ch;
      GstBuffer *outbuffer;
      gint16 *outdata;
      guint pad_slot, N;

      mad_stream_buffer (&mad->stream, mad_input_buffer, mad->tempsize);

      if (mad_frame_decode (&mad->frame, &mad->stream) == -1) {
	/* not enough data, need to wait for next buffer? */
	if (mad->stream.error == MAD_ERROR_BUFLEN) {
	  break;
	} 
        if (!MAD_RECOVERABLE (mad->stream.error)) {
          gst_element_error (GST_ELEMENT (mad), "fatal error decoding stream");
          return;
        }
	/* recoverable errors pass */
	goto next;
      }

      /* calculate beginning of next frame */
      pad_slot = (mad->frame.header.flags & MAD_FLAG_PADDING) ? 1 : 0;

      /* FIXME: we're experiencing division by zero errors, so warn if
       * samplerate is 0 
       * on the other hand, N is not used any further, so why not just
       * remove this bit of code ? */
      if (mad->frame.header.samplerate == 0)
      {
	g_warning ("mad->frame.header.samplerate is 0 !");
      }
      else
      {
        if (mad->frame.header.layer == MAD_LAYER_I)
          N = ((12 * mad->frame.header.bitrate / mad->frame.header.samplerate) + pad_slot) * 4;
        else {
          unsigned int slots_per_frame;

          slots_per_frame = (mad->frame.header.layer == MAD_LAYER_III &&
                             (mad->frame.header.flags & MAD_FLAG_LSF_EXT)) ? 72 : 144;

          N = (slots_per_frame * mad->frame.header.bitrate / mad->frame.header.samplerate) + pad_slot;
        }
      }

      mad_synth_frame (&mad->synth, &mad->frame);

      nchannels = MAD_NCHANNELS (&mad->frame.header);
      nsamples  = mad->synth.pcm.length;
      left_ch   = mad->synth.pcm.samples[0];
      right_ch  = mad->synth.pcm.samples[1];

      /* at this point we can accept seek events */
      mad->can_seek = TRUE;

      gst_mad_update_info (mad, &mad->frame.header);

      outbuffer = gst_buffer_new ();
      outdata = (gint16 *) GST_BUFFER_DATA (outbuffer) = g_malloc (nsamples * nchannels * 2);
      GST_BUFFER_SIZE (outbuffer) = nsamples * nchannels * 2;


      if (mad->frame.header.samplerate == 0)
      {
	g_warning ("mad->frame.header.samplerate is 0 !");
      }
      else
        GST_BUFFER_TIMESTAMP (outbuffer) = mad->sync_point + 
	      				 mad->total_samples * 1000000LL / mad->frame.header.samplerate;

      mad->total_samples += nsamples;

      /* end of new bit */
      while (nsamples--) {
        /* output sample(s) in 16-bit signed native-endian PCM */
        *outdata++ = scale(*left_ch++) & 0xffff;

        if (nchannels == 2) {
          *outdata++ = scale(*right_ch++) & 0xffff;
        }
      }
      if (mad->caps_set == FALSE) {
        if (!gst_pad_try_set_caps (mad->srcpad,
  	      gst_caps_new (
  	        "mad_src",
                "audio/raw",
                gst_props_new (
    	          "format",   GST_PROPS_STRING ("int"),
                  "law",         GST_PROPS_INT (0),
                  "endianness",  GST_PROPS_INT (G_BYTE_ORDER),
                  "signed",      GST_PROPS_BOOLEAN (TRUE),
                  "width",       GST_PROPS_INT (16),
                  "depth",       GST_PROPS_INT (16),
#if MAD_VERSION_MINOR <= 12
                  "rate",        GST_PROPS_INT (mad->header.sfreq),
#else
                  "rate",        GST_PROPS_INT (mad->header.samplerate),
#endif
                  "channels",    GST_PROPS_INT (nchannels),
                  NULL)))) {
          gst_element_error (GST_ELEMENT (mad), "could not set caps on source pad, aborting...");
        }
        mad->caps_set = TRUE;
      }

      gst_pad_push (mad->srcpad, outbuffer);
next:

      /* figure out how many bytes mad consumed */
      consumed = mad->stream.next_frame - mad_input_buffer;

      /* move out pointer to where mad want the next data */
      mad_input_buffer += consumed;
      mad->tempsize -= consumed;

      if (GST_BUFFER_TIMESTAMP (buffer) != -1) {
        if (GST_BUFFER_TIMESTAMP (buffer) > mad->sync_point) {
          mad->sync_point = GST_BUFFER_TIMESTAMP (buffer);
          mad->total_samples = 0;
        }
      }
    }
    memmove (mad->tempbuffer, mad_input_buffer, mad->tempsize);
  }

  gst_buffer_unref (buffer);
}

static GstElementStateReturn
gst_mad_change_state (GstElement *element)
{
  GstMad *mad;

  mad = GST_MAD (element);

  switch (GST_STATE_TRANSITION (element)) {
    case GST_STATE_NULL_TO_READY:
      break;
    case GST_STATE_READY_TO_PAUSED:
      mad_stream_init (&mad->stream);
      mad_frame_init (&mad->frame);
      mad_synth_init (&mad->synth);
      mad->tempsize = 0;
      mad->can_seek = FALSE;
      break;
    case GST_STATE_PAUSED_TO_PLAYING:
      /* do something to get out of the chain function faster */
      break;
    case GST_STATE_PLAYING_TO_PAUSED:
      break;
    case GST_STATE_PAUSED_TO_READY:
      mad_synth_finish (&mad->synth);
      mad_frame_finish (&mad->frame);
      mad_stream_finish (&mad->stream);
      mad->sync_point = 0;
      mad->can_seek = FALSE;
      break;
    case GST_STATE_READY_TO_NULL:
      break;
  }

  parent_class->change_state (element);

  return GST_STATE_SUCCESS;
}

static gboolean
plugin_init (GModule *module, GstPlugin *plugin)
{
  GstElementFactory *factory;

  /* create an elementfactory for the mad element */
  factory = gst_element_factory_new ("mad", GST_TYPE_MAD, &gst_mad_details);
  g_return_val_if_fail (factory != NULL, FALSE);

  gst_element_factory_add_pad_template (factory, 
		  GST_PAD_TEMPLATE_GET (mad_sink_template_factory));
  gst_element_factory_add_pad_template (factory, 
		  GST_PAD_TEMPLATE_GET (mad_src_template_factory));

  gst_plugin_add_feature (plugin, GST_PLUGIN_FEATURE (factory));

  return TRUE;
}

GstPluginDesc plugin_desc = {
  GST_VERSION_MAJOR,
  GST_VERSION_MINOR,
  "mad",
  plugin_init
};