audio library

Original commit message from CVS:
audio library

1 files changed, 152 insertions, 0 deletions

diff --git a/gst-libs/audio/gstaudio.c b/gst-libs/audio/gstaudio.c
new file mode 100644
index 00000000..c18d6c6e
--- /dev/null
+++ b/gst-libs/audio/gstaudio.c
@@ -0,0 +1,152 @@
+/* Gnome-Streamer
+ * 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 "gstaudio.h"
+
+int
+gst_audio_frame_byte_size (GstPad* pad)
+{
+/* calculate byte size of an audio frame
+ * this should be moved closer to the gstreamer core
+ * and be implemented for every mime type IMO
+ * returns 0 if there's an error, or the byte size if everything's ok
+ */
+
+  int width = 0;
+  int channels = 0;
+
+  GstCaps *caps = NULL;
+
+  /* get caps of pad */
+  caps = GST_PAD_CAPS (pad);
+
+  if (caps == NULL)
+    /* ERROR: could not get caps of pad */
+    return 0;
+
+  width    = gst_caps_get_int (caps, "width");
+  channels = gst_caps_get_int (caps, "channels");
+  return (width / 8) * channels; 
+}
+
+long
+gst_audio_frame_length (GstPad* pad, GstBuffer* buf)
+/* calculate length of buffer in frames
+ * this should be moved closer to the gstreamer core
+ * and be implemented for every mime type IMO
+ * returns 0 if there's an error, or the number of frames if everything's ok
+ */
+{
+  int frame_byte_size = 0;
+
+  frame_byte_size = gst_audio_frame_byte_size (pad);
+  if (frame_byte_size == 0)
+    /* error */
+    return 0;
+  /* FIXME: this function assumes the buffer size to be a whole multiple
+   *  	    of the frame byte size
+   */
+  return GST_BUFFER_SIZE (buf) / frame_byte_size;
+}
+
+long
+gst_audio_frame_rate (GstPad *pad)
+/*
+ * calculate frame rate (based on caps of pad)
+ * returns 0 if failed, rate if success
+ */
+{
+  GstCaps *caps = NULL;
+
+  /* get caps of pad */
+  caps = GST_PAD_CAPS (pad);
+
+  if (caps == NULL)
+    /* ERROR: could not get caps of pad */
+    return 0;
+  else
+    return gst_caps_get_int (caps, "rate");
+}
+
+double 
+gst_audio_length (GstPad* pad, GstBuffer* buf)
+{
+/* calculate length in seconds
+ * of audio buffer buf
+ * based on capabilities of pad
+ */
+
+  long bytes = 0;
+  int width = 0;
+  int channels = 0;
+  long rate = 0L;
+
+  double length;
+
+  GstCaps *caps = NULL;
+
+  /* get caps of pad */
+  caps = GST_PAD_CAPS (pad);
+  if (caps == NULL)
+  {
+    /* ERROR: could not get caps of pad */
+    length = 0.0;
+  }
+  else
+  {
+    bytes = GST_BUFFER_SIZE (buf);
+    width    = gst_caps_get_int (caps, "width");
+    channels = gst_caps_get_int (caps, "channels");
+    rate     = gst_caps_get_int (caps, "rate");
+
+    length = (bytes * 8.0) / (double) (rate * channels * width);
+  }
+  return length;
+}
+
+long 
+gst_audio_highest_sample_value (GstPad* pad)
+/* calculate highest possible sample value
+ * based on capabilities of pad
+ */
+{
+  gboolean is_signed = FALSE;
+  gint width = 0;
+  GstCaps *caps = NULL;
+  
+  caps = GST_PAD_CAPS (pad);
+    // FIXME : Please change this to a better warning method !
+  if (caps == NULL)
+    printf ("WARNING: gstaudio: could not get caps of pad !\n");
+  width = gst_caps_get_int (caps, "width");
+  is_signed = gst_caps_get_boolean (caps, "signed");
+  if (is_signed) --width;
+  /* example : 16 bit, signed : samples between -32768 and 32767 */
+  return ((long) (1 << width));
+}
+
+gboolean 
+gst_audio_is_buffer_framed (GstPad* pad, GstBuffer* buf)
+/* check if the buffer size is a whole multiple of the frame size */
+{
+  if (GST_BUFFER_SIZE (buf) % gst_audio_frame_byte_size (pad) == 0)
+    return TRUE;
+  else
+    return FALSE;
+}