dd: Dependency Descriptor RTP header extension (#1170)

* dd: Dependency Descriptor RTP header extension

Defined in:
https://aomediacodec.github.io/av1-rtp-spec/#dependency-descriptor-rtp-header-extension

This work was sponsored by Nvidia Corporation

* dd: fix windows warning

* test: disable dd_print()

* dd: use re_printf()

* dd: remove debugging

* dd: fix for clang analyze

* dd: add limit check for count

CMakeLists.txt

@@ -132,6 +132,7 @@ set(HEADERS
   include/re_convert.h
   include/re_crc32.h
   include/re_dbg.h
+  include/re_dd.h
   include/re_dns.h
   include/re_fmt.h
   include/re_h264.h
@@ -226,6 +227,10 @@ set(SRCS
 
   src/dbg/dbg.c
 
+  src/dd/dd.c
+  src/dd/dd_enc.c
+  src/dd/putbit.c
+
   src/dns/client.c
   src/dns/cstr.c
   src/dns/dname.c

include/re_dd.h

@@ -0,0 +1,109 @@
+/**
+ * @file re_dd.h Dependency Descriptor (DD)
+ *
+ * Copyright (C) 2010 - 2023 Alfred E. Heggestad
+ */
+
+
+/*
+ * Put bits wrapper (XXX: move to common place)
+ */
+
+struct putbit {
+	struct mbuf *mb;
+	size_t bit_pos;
+};
+
+void putbit_init(struct putbit *pb, struct mbuf *mb);
+int  putbit_one(struct putbit *pb, unsigned bit);
+int  putbit_write(struct putbit *pb, unsigned count, unsigned val);
+int  putbit_write_ns(struct putbit *pb, unsigned n, unsigned v);
+
+
+/*
+ * Dependency Descriptor (DD)
+ *
+ * DT:  Decode Target
+ * DTI: Decode Target Indication
+ * SID: Spatial ID
+ * TID: Temporal ID
+ */
+
+/* Constants. */
+enum {
+	DD_MAX_SPATIAL_IDS   =   4u,
+	DD_MAX_TEMPORAL_IDS  =   4u,
+	DD_MAX_TEMPLATES     =   8u,
+	DD_MAX_FDIFFS        =  16u,
+	DD_MAX_DECODE_TARGETS=  16u,
+	DD_MAX_CHAINS        =  32u,
+};
+
+
+/* Decode Target Indication (DTI) */
+enum dd_dti {
+	DD_DTI_NOT_PRESENT = 0,
+	DD_DTI_DISCARDABLE = 1,
+	DD_DTI_SWITCH      = 2,
+	DD_DTI_REQUIRED    = 3,
+};
+
+enum dd_next_layer_idc {
+	DD_SAME_LAYER          = 0,
+	DD_NEXT_TEMPORAL_LAYER = 1,
+	DD_NEXT_SPATIAL_LAYER  = 2,
+	DD_NO_MORE_TEMPLATES   = 3,
+};
+
+/*
+ * https://aomediacodec.github.io/av1-rtp-spec/
+ *     #dependency-descriptor-rtp-header-extension
+ */
+struct dd {
+
+	/* Mandatory Descriptor Fields */
+	unsigned start_of_frame:1;
+	unsigned end_of_frame:1;
+	unsigned frame_dependency_template_id:6;
+	uint16_t frame_number;
+
+	// TODO: needed?
+	bool ext;
+
+	unsigned template_dependency_structure_present_flag:1;
+	unsigned active_decode_targets_present_flag:1;
+	unsigned custom_dtis_flag:1;
+	unsigned custom_fdiffs_flag:1;
+	unsigned custom_chains_flag:1;
+
+	unsigned active_decode_targets_bitmask;
+	unsigned template_id_offset:6;
+	uint8_t dt_cnt;
+	uint8_t template_cnt;
+	uint8_t max_spatial_id;
+
+	uint8_t template_spatial_id[DD_MAX_TEMPLATES];
+	uint8_t template_temporal_id[DD_MAX_TEMPLATES];
+
+	/* render_resolutions */
+	bool resolutions_present_flag;
+	uint16_t max_render_width_minus_1[DD_MAX_SPATIAL_IDS];
+	uint16_t max_render_height_minus_1[DD_MAX_SPATIAL_IDS];
+	uint8_t render_count;
+
+	/* type: enum dd_dti */
+	uint8_t template_dti[DD_MAX_TEMPLATES][DD_MAX_DECODE_TARGETS];
+
+	/* template fdiffs */
+	uint8_t template_fdiff[DD_MAX_TEMPLATES][DD_MAX_FDIFFS];
+	uint8_t template_fdiff_cnt[DD_MAX_TEMPLATES];
+
+	/* template chains */
+	uint8_t decode_target_protected_by[DD_MAX_DECODE_TARGETS];
+	uint8_t template_chain_fdiff[DD_MAX_TEMPLATES][DD_MAX_CHAINS];
+	uint8_t chain_cnt;
+};
+
+int  dd_encode(struct mbuf *mb, const struct dd *dd);
+int  dd_decode(struct dd *dd, const uint8_t *buf, size_t sz);
+void dd_print(const struct dd *dd);

include/re_h264.h

@@ -105,3 +105,21 @@ int  h264_stap_encode(struct mbuf *mb, const uint8_t *frame,
 		      size_t frame_sz);
 int  h264_stap_decode_annexb(struct mbuf *mb_frame, struct mbuf *mb_pkt);
 int  h264_stap_decode_annexb_long(struct mbuf *mb_frame, struct mbuf *mb_pkt);
+
+
+/*
+ * Get bits wrapper
+ */
+
+struct getbit {
+	const uint8_t *buf;
+	size_t pos;
+	size_t end;
+};
+
+void     getbit_init(struct getbit *gb, const uint8_t *buf, size_t size);
+size_t   getbit_get_left(const struct getbit *gb);
+unsigned get_bit(struct getbit *gb);
+int      get_ue_golomb(struct getbit *gb, unsigned *valp);
+unsigned get_bits(struct getbit *gb, unsigned n);
+unsigned getbit_read_ns(struct getbit *gb, unsigned n);

src/av1/getbit.c

@@ -0,0 +1,61 @@
+/**
+ * @file getbit.c Get bits helper
+ *
+ * Copyright (C) 2023 Alfred E. Heggestad
+ */
+
+#include <re.h>
+#include <re_av1.h>
+
+
+#define DEBUG_MODULE "av1"
+#define DEBUG_LEVEL 5
+#include <re_dbg.h>
+
+
+void getbit_init(struct getbit *gb, const uint8_t *buf, size_t size_bits)
+{
+	if (!gb)
+		return;
+
+	gb->buf = buf;
+	gb->pos = 0;
+	gb->end = size_bits;
+}
+
+
+size_t getbit_get_left(const struct getbit *gb)
+{
+	if (!gb)
+		return 0;
+
+	if (gb->end > gb->pos)
+		return gb->end - gb->pos;
+	else
+		return 0;
+}
+
+
+unsigned get_bit(struct getbit *gb)
+{
+	register unsigned tmp;
+
+	if (!gb)
+		return 0;
+
+	if (gb->pos >= gb->end) {
+		DEBUG_WARNING("get_bit: read past end"
+			" (%zu >= %zu)\n", gb->pos, gb->end);
+		assert(0);
+		return 0;
+	}
+
+	const uint8_t *p = gb->buf;
+	tmp = ((*(p + (gb->pos >> 0x3))) >> (0x7 - (gb->pos & 0x7))) & 0x1;
+
+	++gb->pos;
+
+	return tmp;
+}
+
+