SMPTE RDD 08 (OP-47 subtitles)

smpte/rdd08.h

@@ -0,0 +1,126 @@
+/*****************************************************************************
+ * rdd08.h: SMPTE RDD 8 Teletext Subtitles for HDTV (aka OP-47)
+ *****************************************************************************
+ * Copyright (C) 2016 OpenHeadend
+ *
+ * Authors: Christophe Massiot <cmassiot@openheadend.tv>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject
+ * to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *****************************************************************************/
+
+/*
+ * Normative references:
+ *  - SMPTE RDD 8-2008
+ */
+
+#ifndef __BITSTREAM_SMPTE_RDD08_H__
+#define __BITSTREAM_SMPTE_RDD08_H__
+
+#include <stdint.h>   /* uint8_t, uint16_t, etc... */
+#include <stdbool.h>  /* bool */
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/*****************************************************************************
+ * SMPTE RDD 8 Subtitling Distribution Packet
+ *****************************************************************************/
+#define RDD08SDP_HEADER_SIZE        8
+#define RDD08SDP_FOOTER_SIZE        4
+#define RDD08SDP_B_SIZE             45
+
+#define RDD08SDP_IDENT1             0x51
+#define RDD08SDP_IDENT2             0x15
+#define RDD08SDP_FOOTER             0x74
+
+#define RDD08SDP_FORMAT_WST         0x2
+
+static inline uint8_t rdd08sdp_get_length(const uint16_t *p_rdd08)
+{
+    return p_rdd08[2] & 0xff;
+}
+
+static inline uint8_t rdd08sdp_get_format(const uint16_t *p_rdd08)
+{
+    return p_rdd08[3] & 0xff;
+}
+
+static inline uint8_t rdd08sdp_get_a(const uint16_t *p_rdd08, uint8_t n)
+{
+    return p_rdd08[4 + n] & 0xff;
+}
+
+static inline uint8_t rdd08sdpa_get_line(uint8_t i_rdd08a)
+{
+    return i_rdd08a & 0x1f;
+}
+
+static inline bool rdd08sdpa_get_field(uint8_t i_rdd08a)
+{
+    return i_rdd08a & 0x80;
+}
+
+static inline uint16_t *rdd08sdp_get_b(const uint16_t *p_rdd08, uint8_t n)
+{
+    const uint16_t *b = p_rdd08 + RDD08SDP_HEADER_SIZE;
+    unsigned int i;
+    for (i = 0; i < n; i++)
+        if (rdd08sdp_get_a(p_rdd08, i))
+            b += RDD08SDP_B_SIZE;
+    return (uint16_t *)b;
+}
+
+static inline uint8_t rdd08sdp_get_footer(const uint16_t *p_rdd08)
+{
+    uint8_t i_length = rdd08sdp_get_length(p_rdd08);
+    return p_rdd08[i_length - 4] & 0xff;
+}
+
+static inline uint16_t rdd08sdp_get_counter(const uint16_t *p_rdd08)
+{
+    uint8_t i_length = rdd08sdp_get_length(p_rdd08);
+    return ((p_rdd08[i_length - 3] & 0xff) << 8) |
+           (p_rdd08[i_length - 2] & 0xff);
+}
+
+static inline bool rdd08sdp_check_cs(const uint16_t *p_rdd08)
+{
+    uint8_t i_length = rdd08sdp_get_length(p_rdd08);
+    uint8_t i_cs = 0;
+    unsigned int i;
+    for (i = 0; i < i_length; i++)
+        i_cs += p_rdd08[i] & 0xff;
+    return !i_cs;
+}
+
+static inline bool rdd08sdp_validate(const uint16_t *p_rdd08)
+{
+    uint8_t i_length = rdd08sdp_get_length(p_rdd08);
+    const uint16_t *b = rdd08sdp_get_b(p_rdd08, 5);
+    return b <= p_rdd08 + i_length - 4;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif