--- /dev/null
+/* GStreamer audio helper functions for IEC 61937 payloading
+ * (c) 2011 Intel Corporation
+ * 2011 Collabora Multimedia
+ * 2011 Arun Raghavan <arun.raghavan@collabora.co.uk>
+ *
+ * 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.
+ */
+
+/**
+ * SECTION:gstaudioiec61937
+ * @short_description: Utility functions for IEC 61937 payloading
+ *
+ * This module contains some helper functions for encapsulating various
+ * audio formats in IEC 61937 headers and padding.
+ *
+ * Since: 0.10.35
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string.h>
+#include "gstaudioiec61937.h"
+
+#define IEC61937_HEADER_SIZE 8
+#define IEC61937_PAYLOAD_SIZE_AC3 (1536 * 4)
+#define IEC61937_PAYLOAD_SIZE_EAC3 (6144 * 4)
+
+static gint
+caps_get_int_field (const GstCaps * caps, const gchar * field)
+{
+ const GstStructure *st;
+ gint ret = 0;
+
+ st = gst_caps_get_structure (caps, 0);
+ gst_structure_get_int (st, field, &ret);
+
+ return ret;
+}
+
+static const gchar *
+caps_get_string_field (const GstCaps * caps, const gchar * field)
+{
+ const GstStructure *st = gst_caps_get_structure (caps, 0);
+ return gst_structure_get_string (st, field);
+}
+
+/**
+ * gst_audio_iec61937_frame_size
+ * @type: the type of data to be payloaded as a #GstBufferFormatType
+ *
+ * Returns 0 if the given @type is not supported or cannot be payloaded, else
+ * returns the size of the buffer expected by gst_audio_iec61937_payload() for
+ * payloading @type.
+ *
+ * Since: 0.10.35
+ */
+guint
+gst_audio_iec61937_frame_size (const GstRingBufferSpec * spec)
+{
+ switch (spec->type) {
+ case GST_BUFTYPE_AC3:
+ return IEC61937_PAYLOAD_SIZE_AC3;
+
+ case GST_BUFTYPE_EAC3:
+ /* Check that the parser supports /some/ alignment. Need to be less
+ * strict about this at checking time since the alignment is dynamically
+ * set at the moment. */
+ if (caps_get_string_field (spec->caps, "alignment"))
+ return IEC61937_PAYLOAD_SIZE_EAC3;
+ else
+ return 0;
+
+ case GST_BUFTYPE_DTS:
+ {
+ gint dts_frame_size = caps_get_int_field (spec->caps, "frame-size");
+ gint iec_frame_size = caps_get_int_field (spec->caps, "block-size") * 4;
+
+ /* Note: this will also (correctly) fail if either field is missing */
+ if (iec_frame_size >= (dts_frame_size + IEC61937_HEADER_SIZE))
+ return iec_frame_size;
+ else
+ return 0;
+ }
+
+ case GST_BUFTYPE_MPEG:
+ {
+ int version, layer, channels, frames;
+
+ version = caps_get_int_field (spec->caps, "mpegaudioversion");
+ layer = caps_get_int_field (spec->caps, "layer");
+ channels = caps_get_int_field (spec->caps, "channels");
+
+ /* Bail out if we can't figure out either, if it's MPEG 2.5, or if it's
+ * MP3 with multichannel audio */
+ if (!version || !layer || version == 3 || channels > 2)
+ return 0;
+
+ if (version == 1 && layer == 1)
+ frames = 384;
+ else if (version == 2 && layer == 1 && spec->rate < 32000)
+ frames = 768;
+ else if (version == 2 && layer == 1 && spec->rate < 32000)
+ frames = 2304;
+ else
+ frames = 1152;
+
+ return frames * 4;
+ }
+
+ default:
+ return 0;
+ }
+}
+
+/**
+ * gst_audio_iec61937_payload
+ * @src: a buffer containing the data to payload
+ * @src_n: size of @src in bytes
+ * @dst: the destination buffer to store the payloaded contents in. Should not
+ * overlap with @src
+ * @dst_n: size of @dst in bytes
+ * @type: the type of data in @src
+ *
+ * Payloads @src in the form specified by IEC 61937 for @type and stores
+ * the result in @dst. @src must contain exactly one frame of data and the
+ * frame is not checked for errors.
+ *
+ * Returns: transfer-full: #TRUE if the payloading was successful, #FALSE
+ * otherwise.
+ *
+ * Since: 0.10.35
+ */
+gboolean
+gst_audio_iec61937_payload (const guint8 * src, guint src_n, guint8 * dst,
+ guint dst_n, const GstRingBufferSpec * spec)
+{
+ guint i, tmp;
+#if G_BYTE_ORDER == G_BIG_ENDIAN
+ guint8 zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5, six = 6,
+ seven = 7;
+#else
+ /* We need to send the data byte-swapped */
+ guint8 zero = 1, one = 0, two = 3, three = 2, four = 5, five = 4, six = 7,
+ seven = 6;
+#endif
+
+ g_return_val_if_fail (src != NULL, FALSE);
+ g_return_val_if_fail (dst != NULL, FALSE);
+ g_return_val_if_fail (src != dst, FALSE);
+ g_return_val_if_fail (dst_n >= gst_audio_iec61937_frame_size (spec), FALSE);
+
+ if (dst_n < src_n + IEC61937_HEADER_SIZE)
+ return FALSE;
+
+ /* Pa, Pb */
+ dst[zero] = 0xF8;
+ dst[one] = 0x72;
+ dst[two] = 0x4E;
+ dst[three] = 0x1F;
+
+ switch (spec->type) {
+ case GST_BUFTYPE_AC3:
+ {
+ g_return_val_if_fail (src_n >= 6, FALSE);
+
+ /* Pc: bit 13-15 - stream number (0)
+ * bit 11-12 - reserved (0)
+ * bit 8-10 - bsmod from AC3 frame */
+ dst[four] = src[5] & 0x7;
+ /* Pc: bit 7 - error bit (0)
+ * bit 5-6 - subdata type (0)
+ * bit 0-4 - data type (1) */
+ dst[five] = 1;
+ /* Pd: bit 15-0 - frame size in bits */
+ tmp = src_n * 8;
+ dst[six] = (guint8) (tmp >> 8);
+ dst[seven] = (guint8) (tmp & 0xff);
+
+ break;
+ }
+
+ case GST_BUFTYPE_EAC3:
+ {
+ if (g_str_equal (caps_get_string_field (spec->caps, "alignment"),
+ "iec61937"))
+ return FALSE;
+
+ /* Pc: bit 13-15 - stream number (0)
+ * bit 11-12 - reserved (0)
+ * bit 8-10 - bsmod from E-AC3 frame if present */
+ /* FIXME: this works, but nicer if we can put in the actual bsmod */
+ dst[four] = 0;
+ /* Pc: bit 7 - error bit (0)
+ * bit 5-6 - subdata type (0)
+ * bit 0-4 - data type (21) */
+ dst[five] = 21;
+ /* Pd: bit 15-0 - frame size in bytes */
+ dst[six] = ((guint16) src_n) >> 8;
+ dst[seven] = ((guint16) src_n) & 0xff;
+
+ break;
+ }
+
+ case GST_BUFTYPE_DTS:
+ {
+ int blocksize = caps_get_int_field (spec->caps, "block-size");
+
+ g_return_val_if_fail (src_n != 0, FALSE);
+
+ if (blocksize == 0)
+ return FALSE;
+
+ /* Pc: bit 13-15 - stream number (0)
+ * bit 11-12 - reserved (0)
+ * bit 8-10 - for DTS type I-III (0) */
+ dst[four] = 0;
+ /* Pc: bit 7 - error bit (0)
+ * bit 5-6 - reserved (0)
+ * bit 0-4 - data type (11 = type I, 12 = type II,
+ * 13 = type III) */
+ dst[five] = 11 + (blocksize / 1024);
+ /* Pd: bit 15-0 - frame size in bytes */
+ dst[six] = ((guint16) src_n) >> 8;
+ dst[seven] = ((guint16) src_n) & 0xff;
+ break;
+ }
+
+ case GST_BUFTYPE_MPEG:
+ {
+ int version, layer;
+
+ version = caps_get_int_field (spec->caps, "mpegaudioversion");
+ layer = caps_get_int_field (spec->caps, "layer");
+
+ g_return_val_if_fail (version > 0 && layer > 0, FALSE);
+
+ /* NOTE: multichannel audio (MPEG-2) is not supported */
+
+ /* Pc: bit 13-15 - stream number (0)
+ * bit 11-12 - reserved (0)
+ * bit 9-10 - 0 - no dynamic range control
+ * - 2 - dynamic range control exists
+ * - 1,3 - reserved
+ * bit 8 - Normal (0) or Karaoke (1) mode */
+ dst[four] = 0;
+ /* Pc: bit 7 - error bit (0)
+ * bit 5-6 - reserved (0)
+ * bit 0-4 - data type (04 = MPEG 1, Layer 1
+ * 05 = MPEG 1, Layer 2, 3 / MPEG 2, w/o ext.
+ * 06 = MPEG 2, with extension
+ * 08 - MPEG 2 LSF, Layer 1
+ * 09 - MPEG 2 LSF, Layer 2
+ * 10 - MPEG 2 LSF, Layer 3 */
+ if (version == 1 && layer == 1)
+ dst[five] = 0x04;
+ else if ((version == 1 && (layer == 2 || layer == 3)) ||
+ (version == 2 && spec->rate >= 32000))
+ dst[five] = 0x05;
+ else if (version == 2 && layer == 1 && spec->rate < 32000)
+ dst[five] = 0x08;
+ else if (version == 2 && layer == 2 && spec->rate < 32000)
+ dst[five] = 0x09;
+ else if (version == 2 && layer == 3 && spec->rate < 32000)
+ dst[five] = 0x0A;
+ else
+ g_return_val_if_reached (FALSE);
+ /* Pd: bit 15-0 - frame size in bits */
+ dst[six] = ((guint16) src_n * 8) >> 8;
+ dst[seven] = ((guint16) src_n * 8) & 0xff;
+
+ break;
+ }
+
+ default:
+ return FALSE;
+ }
+
+ /* Copy the payload */
+ i = 8;
+
+#if G_BYTE_ORDER == G_BIG_ENDIAN
+ memcpy (dst + i, src, src_n);
+#else
+ /* Byte-swapped again */
+ /* FIXME: orc-ify this */
+ for (tmp = 1; tmp < src_n; tmp += 2) {
+ dst[i + tmp - 1] = src[tmp];
+ dst[i + tmp] = src[tmp - 1];
+ }
+ /* Do we have 1 byte remaining? */
+ if (src_n % 2) {
+ dst[i + src_n - 1] = 0;
+ dst[i + src_n] = src[src_n - 1];
+ i++;
+ }
+#endif
+
+ i += src_n;
+
+ /* Zero the rest */
+ memset (dst + i, 0, dst_n - i);
+
+ return TRUE;
+}
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