vid-scratch: Add consolidated versions of my experiments from 2025-02-XXlukeshu/vid-scratch

1 files changed, 259 insertions, 0 deletions

diff --git a/vid-scratch/common.h b/vid-scratch/common.h
new file mode 100644
index 0000000..91f94fd
--- /dev/null
+++ b/vid-scratch/common.h
@@ -0,0 +1,259 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>   /* for perror() */
+#include <string.h>  /* for memcpy() */
+#include <stdlib.h>  /* for realloc(), free() */
+#include <unistd.h>  /* for write() */
+
+#define LM_ARRAY_LEN(ary)       (sizeof(ary)/sizeof((ary)[0]))
+#define LM_CEILDIV(n, d)        ( ((n)+(d)-1) / (d) )
+#define LM_NEXT_POWER_OF_2(x)   ( (x) ? 1ULL<<((sizeof(unsigned long long)*8)-__builtin_clzll(x)) : 1)
+#define LM_CAT2(a, b)           a ## b
+#define LM_CAT2_(a, b)          LM_CAT2(a, b)
+#define assert_notreached(msg)  assert(false)
+
+struct buf {
+	uint8_t *dat;
+	size_t   len;
+	size_t   cap;
+};
+
+void append(struct buf *buf, void *dat, size_t len) {
+	assert(buf);
+	assert(len == 0 || dat);
+
+	if (buf->len + len > buf->cap) {
+		buf->cap = LM_NEXT_POWER_OF_2(buf->len + len);
+		buf->dat = realloc(buf->dat, buf->cap);
+		assert(buf->dat);
+	}
+	memcpy(&buf->dat[buf->len], dat, len);
+	buf->len += len;
+}
+
+void append_u32be(struct buf *buf, uint32_t val) {
+	assert(buf);
+
+	uint8_t dat[4] = {
+		(val>>(8*3))&0xFF,
+		(val>>(8*2))&0xFF,
+		(val>>(8*1))&0xFF,
+		(val>>(8*0))&0xFF,
+	};
+	append(buf, dat, sizeof(dat));
+}
+
+bool xwrite(int fd, uint8_t *dat, size_t len) {
+	assert(len == 0 || dat);
+
+	for (size_t done = 0; done < len;) {
+		ssize_t n = write(fd, &dat[done], len-done);
+		if (n < 0) {
+			perror("write");
+			return true;
+		}
+		done += n;
+	}
+	return false;
+}
+
+/* NUT ************************************************************************/
+
+/* Magic values.  *****************************************/
+uint8_t nut_file_id_string[]      = "nut/multimedia container"; /* including NUL terminator */
+uint8_t nut_startcode_main[]      = {'N', 'M', 0x7A, 0x56, 0x1F, 0x5F, 0x04, 0xAD };
+uint8_t nut_startcode_stream[]    = {'N', 'S', 0x11, 0x40, 0x5B, 0xF2, 0xF9, 0xDB };
+uint8_t nut_startcode_syncpoint[] = {'N', 'K', 0xE4, 0xAD, 0xEE, 0xCA, 0x45, 0x69 };
+uint8_t nut_startcode_index[]     = {'N', 'X', 0xDD, 0x67, 0x2F, 0x23, 0xE6, 0x4E };
+uint8_t nut_startcode_info[]      = {'N', 'I', 0xAB, 0x68, 0xB5, 0x96, 0xBA, 0x78 };
+
+#define NUT_FRAMEFLAG_KEY         (1<< 0)
+#define NUT_FRAMEFLAG_EOR         (1<< 1)
+#define _NUT_FRAMEFLAG_2          (1<< 2)
+#define NUT_FRAMEFLAG_CODED_PTS   (1<< 3)
+#define NUT_FRAMEFLAG_STREAM_ID   (1<< 4)
+#define NUT_FRAMEFLAG_SIZE_MSB    (1<< 5)
+#define NUT_FRAMEFLAG_CHECKSUM    (1<< 6)
+#define NUT_FRAMEFLAG_RESERVED    (1<< 7)
+#define NUT_FRAMEFLAG_SM_DATA     (1<< 8)
+#define _NUT_FRAMEFLAG_9          (1<< 9)
+#define NUT_FRAMEFLAG_HEADER_IDX  (1<<10)
+#define NUT_FRAMEFLAG_MATCH_TIME  (1<<11)
+#define NUT_FRAMEFLAG_CODED       (1<<12)
+#define NUT_FRAMEFLAG_INVALID     (1<<13)
+
+#define NUT_MAINFLAG_BROADCAST_MODE (1<< 0)
+#define NUT_MAINFLAG_PIPE_MODE      (1<< 1)
+
+#define NUT_UNKNOWN_MATCH_TIME (1-(UINT64_C(1)<<62))
+
+enum nut_stream_class {
+	NUT_STREAMCLASS_VIDEO     = 0,
+	NUT_STREAMCLASS_AUDIO     = 1,
+	NUT_STREAMCLASS_SUBTITLES = 2,
+	NUT_STREAMCLASS_USERDATA  = 3,
+};
+
+#define NUT_STREAMFLAG_FIXED_FPS (1<< 1)
+
+enum nut_colorspace {
+	NUT_COLORSPACE_UNKNOWN         =  0,
+	NUT_COLORSPACE_ITU642_TRUNC    =  1,
+	NUT_COLORSPACE_ITU709_TRUNC    =  2,
+	NUT_COLORSPACE_ITU642_FULL     = 17,
+	NUT_COLORSPACE_ITU709_FILL     = 18,
+};
+
+/* Basic fixed-length types.  *****************************/
+
+void nut_append_u8(struct buf *buf, uint8_t val) {
+	assert(buf);
+
+	append(buf, &val, 1);
+}
+
+void nut_append_u32(struct buf *buf, uint32_t val) {
+	assert(buf);
+
+	append_u32be(buf, val);
+}
+
+/* Basic variable-length types.  **************************/
+
+void nut_append_vu(struct buf *buf, uint64_t val) {
+	assert(buf);
+
+	uint8_t dat[10] = {
+		0x80|((val>>(7*9))&0x7F),
+		0x80|((val>>(7*8))&0x7F),
+		0x80|((val>>(7*7))&0x7F),
+		0x80|((val>>(7*6))&0x7F),
+		0x80|((val>>(7*5))&0x7F),
+		0x80|((val>>(7*4))&0x7F),
+		0x80|((val>>(7*3))&0x7F),
+		0x80|((val>>(7*2))&0x7F),
+		0x80|((val>>(7*1))&0x7F),
+		0x00|((val>>(7*0))&0x7F),
+	};
+	uint8_t skip = 0;
+	while (dat[skip] == 0x80)
+		skip++;
+	append(buf, &dat[skip], sizeof(dat)-skip);
+}
+
+void nut_append_vs(struct buf *buf, int64_t val) {
+	assert(buf);
+	assert((val < 0 ? -val : val) <= UINT64_MAX>>1);
+
+	uint64_t temp;
+	if (val > 0)
+		temp = val << 1;
+	else
+		temp = ((-val) << 1) | 1;
+	temp--;
+	nut_append_vu(buf, temp);
+}
+
+void nut_append_vb(struct buf *buf, void *dat, size_t len) {
+	assert(buf);
+	assert(len == 0 || dat);
+
+	nut_append_vu(buf, len);
+	append(buf, dat, len);
+}
+
+#define nut_append_vb_str(buf, str) nut_append_vb(buf, str, sizeof(str)-1)
+
+/* Mid-level.  ********************************************/
+
+uint32_t nut_crc32(uint8_t *dat, int len){
+	assert(len == 0 || dat);
+
+	/* "Generator polynomial is 0x104C11DB7."  */
+	static const uint32_t table[16] = {
+		0x00000000, 0x04C11DB7, 0x09823B6E, 0x0D4326D9,
+		0x130476DC, 0x17C56B6B, 0x1A864DB2, 0x1E475005,
+		0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6, 0x2B4BCB61,
+		0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD,
+	};
+
+	/* "Starting value is zero."  */
+	uint32_t crc = 0;
+
+	while (len--) {
+		crc ^= *dat++ << 24;
+		crc = (crc<<4) ^ table[crc>>28];
+		crc = (crc<<4) ^ table[crc>>28];
+	}
+	return crc;
+}
+
+void nut_append_packet(struct buf *buf, uint8_t *startcode, void *data, size_t len) {
+	assert(buf);
+	assert(startcode);
+	assert(len == 0 || data);
+
+	size_t packet_beg = buf->len;
+	append(buf, startcode, 8);
+	nut_append_vu(buf, len+4);
+	if (len+4 > 4096)
+		nut_append_u32(buf, nut_crc32(&buf->dat[packet_beg], buf->len - packet_beg));
+	size_t data_beg = buf->len;
+	append(buf, data, len);
+	nut_append_u32(buf, nut_crc32(&buf->dat[data_beg], buf->len - data_beg));
+}
+
+[[gnu::nonstring]] char font[10][8*4] = {
+	"   ##   "
+	"  #  #  "
+	"  #  #  "
+	"   ##   ",
+
+	"    #   "
+	"   ##   "
+	"    #   "
+	"   ###  ",
+
+	"   ##   "
+	"  #  #  "
+	"    #   "
+	"  ####  ",
+
+	"   ##   "
+	"     #  "
+	"     #  "
+	"   ##   ",
+
+	"    ##  "
+	"   # #  "
+	"  ####  "
+	"     #  ",
+
+	"  ####  "
+	"  ###   "
+	"     #  "
+	"  ###   ",
+
+	"  #     "
+	"  ###   "
+	"  #  #  "
+	"   ##   ",
+
+	"  ####  "
+	"    #   "
+	"   #    "
+	"   #    ",
+
+	"   ##   "
+	"  #  #  "
+	"  ####  "
+	"   ##   ",
+
+	"   ##   "
+	"  #  #  "
+	"   ###  "
+	"     #  ",
+};
+static_assert(LM_ARRAY_LEN(font) == 10);
+static_assert(sizeof(font[0]) == 32);