lavc: Add coded bitstream read/write support for AV1

1 files changed, 1320 insertions, 0 deletions

diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
new file mode 100644
index 0000000000..9bac9dde09
--- /dev/null
+++ b/libavcodec/cbs_av1.c
@@ -0,0 +1,1320 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/pixfmt.h"
+
+#include "cbs.h"
+#include "cbs_internal.h"
+#include "cbs_av1.h"
+#include "internal.h"
+
+
+static int cbs_av1_read_uvlc(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                             const char *name, uint32_t *write_to,
+                             uint32_t range_min, uint32_t range_max)
+{
+    uint32_t value;
+    int position, zeroes, i, j;
+    char bits[65];
+
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    zeroes = i = 0;
+    while (1) {
+        if (get_bits_left(gbc) < zeroes + 1) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid uvlc code at "
+                   "%s: bitstream ended.\n", name);
+            return AVERROR_INVALIDDATA;
+        }
+
+        if (get_bits1(gbc)) {
+            bits[i++] = '1';
+            break;
+        } else {
+            bits[i++] = '0';
+            ++zeroes;
+        }
+    }
+
+    if (zeroes >= 32) {
+        value = MAX_UINT_BITS(32);
+    } else {
+        value = get_bits_long(gbc, zeroes);
+
+        for (j = 0; j < zeroes; j++)
+            bits[i++] = (value >> (zeroes - j - 1) & 1) ? '1' : '0';
+
+        value += (1 << zeroes) - 1;
+    }
+
+    if (ctx->trace_enable) {
+        bits[i] = 0;
+        ff_cbs_trace_syntax_element(ctx, position, name, NULL,
+                                    bits, value);
+    }
+
+    if (value < range_min || value > range_max) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+               "%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
+               name, value, range_min, range_max);
+        return AVERROR_INVALIDDATA;
+    }
+
+    *write_to = value;
+    return 0;
+}
+
+static int cbs_av1_write_uvlc(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                              const char *name, uint32_t value,
+                              uint32_t range_min, uint32_t range_max)
+{
+    uint32_t v;
+    int position, zeroes;
+
+    if (value < range_min || value > range_max) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+               "%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
+               name, value, range_min, range_max);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (ctx->trace_enable)
+        position = put_bits_count(pbc);
+
+    if (value == 0) {
+        zeroes = 0;
+        put_bits(pbc, 1, 1);
+    } else {
+        zeroes = av_log2(value + 1);
+        v = value - (1 << zeroes) + 1;
+        put_bits(pbc, zeroes + 1, 1);
+        put_bits(pbc, zeroes, v);
+    }
+
+    if (ctx->trace_enable) {
+        char bits[65];
+        int i, j;
+        i = 0;
+        for (j = 0; j < zeroes; j++)
+            bits[i++] = '0';
+        bits[i++] = '1';
+        for (j = 0; j < zeroes; j++)
+            bits[i++] = (v >> (zeroes - j - 1) & 1) ? '1' : '0';
+        bits[i++] = 0;
+        ff_cbs_trace_syntax_element(ctx, position, name, NULL,
+                                    bits, value);
+    }
+
+    return 0;
+}
+
+static int cbs_av1_read_leb128(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                               const char *name, uint64_t *write_to)
+{
+    uint64_t value;
+    int position, err, i;
+
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    value = 0;
+    for (i = 0; i < 8; i++) {
+        int subscript[2] = { 1, i };
+        uint32_t byte;
+        err = ff_cbs_read_unsigned(ctx, gbc, 8, "leb128_byte[i]", subscript,
+                                   &byte, 0x00, 0xff);
+        if (err < 0)
+            return err;
+
+        value |= (uint64_t)(byte & 0x7f) << (i * 7);
+        if (!(byte & 0x80))
+            break;
+    }
+
+    if (ctx->trace_enable)
+        ff_cbs_trace_syntax_element(ctx, position, name, NULL, "", value);
+
+    *write_to = value;
+    return 0;
+}
+
+static int cbs_av1_write_leb128(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                                const char *name, uint64_t value)
+{
+    int position, err, len, i;
+    uint8_t byte;
+
+    len = (av_log2(value) + 7) / 7;
+
+    if (ctx->trace_enable)
+        position = put_bits_count(pbc);
+
+    for (i = 0; i < len; i++) {
+        int subscript[2] = { 1, i };
+
+        byte = value >> (7 * i) & 0x7f;
+        if (i < len - 1)
+            byte |= 0x80;
+
+        err = ff_cbs_write_unsigned(ctx, pbc, 8, "leb128_byte[i]", subscript,
+                                    byte, 0x00, 0xff);
+        if (err < 0)
+            return err;
+    }
+
+    if (ctx->trace_enable)
+        ff_cbs_trace_syntax_element(ctx, position, name, NULL, "", value);
+
+    return 0;
+}
+
+static int cbs_av1_read_su(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                           int width, const char *name,
+                           const int *subscripts, int32_t *write_to)
+{
+    uint32_t magnitude;
+    int position, sign;
+    int32_t value;
+
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    if (get_bits_left(gbc) < width + 1) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid signed value at "
+               "%s: bitstream ended.\n", name);
+        return AVERROR_INVALIDDATA;
+    }
+
+    magnitude = get_bits(gbc, width);
+    sign      = get_bits1(gbc);
+    value     = sign ? -(int32_t)magnitude : magnitude;
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (i = 0; i < width; i++)
+            bits[i] = magnitude >> (width - i - 1) & 1 ? '1' : '0';
+        bits[i] = sign ? '1' : '0';
+        bits[i + 1] = 0;
+
+        ff_cbs_trace_syntax_element(ctx, position,
+                                    name, subscripts, bits, value);
+    }
+
+    *write_to = value;
+    return 0;
+}
+
+static int cbs_av1_write_su(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                            int width, const char *name,
+                            const int *subscripts, int32_t value)
+{
+    uint32_t magnitude;
+    int sign;
+
+    if (put_bits_left(pbc) < width + 1)
+        return AVERROR(ENOSPC);
+
+    sign      = value < 0;
+    magnitude = sign ? -value : value;
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (i = 0; i < width; i++)
+            bits[i] = magnitude >> (width - i - 1) & 1 ? '1' : '0';
+        bits[i] = sign ? '1' : '0';
+        bits[i + 1] = 0;
+
+        ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
+                                    name, subscripts, bits, value);
+    }
+
+    put_bits(pbc, width, magnitude);
+    put_bits(pbc, 1, sign);
+
+    return 0;
+}
+
+static int cbs_av1_read_ns(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                           uint32_t n, const char *name,
+                           const int *subscripts, uint32_t *write_to)
+{
+    uint32_t w, m, v, extra_bit, value;
+    int position;
+
+    av_assert0(n > 0);
+
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    w = av_log2(n) + 1;
+    m = (1 << w) - n;
+
+    if (get_bits_left(gbc) < w) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid non-symmetric value at "
+               "%s: bitstream ended.\n", name);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (w - 1 > 0)
+        v = get_bits(gbc, w - 1);
+    else
+        v = 0;
+
+    if (v < m) {
+        value = v;
+    } else {
+        extra_bit = get_bits1(gbc);
+        value = (v << 1) - m + extra_bit;
+    }
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (i = 0; i < w - 1; i++)
+            bits[i] = (v >> i & 1) ? '1' : '0';
+        if (v >= m)
+            bits[i++] = extra_bit ? '1' : '0';
+        bits[i] = 0;
+
+        ff_cbs_trace_syntax_element(ctx, position,
+                                    name, subscripts, bits, value);
+    }
+
+    *write_to = value;
+    return 0;
+}
+
+static int cbs_av1_write_ns(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                            uint32_t n, const char *name,
+                            const int *subscripts, uint32_t value)
+{
+    uint32_t w, m, v, extra_bit;
+    int position;
+
+    if (value > n) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+               "%"PRIu32", but must be in [0,%"PRIu32"].\n",
+               name, value, n);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (ctx->trace_enable)
+        position = put_bits_count(pbc);
+
+    w = av_log2(n) + 1;
+    m = (1 << w) - n;
+
+    if (put_bits_left(pbc) < w)
+        return AVERROR(ENOSPC);
+
+    if (value < m) {
+        v = value;
+        put_bits(pbc, w - 1, v);
+    } else {
+        v = m + ((value - m) >> 1);
+        extra_bit = (value - m) & 1;
+        put_bits(pbc, w - 1, v);
+        put_bits(pbc, 1, extra_bit);
+    }
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (i = 0; i < w - 1; i++)
+            bits[i] = (v >> i & 1) ? '1' : '0';
+        if (value >= m)
+            bits[i++] = extra_bit ? '1' : '0';
+        bits[i] = 0;
+
+        ff_cbs_trace_syntax_element(ctx, position,
+                                    name, subscripts, bits, value);
+    }
+
+    return 0;
+}
+
+static int cbs_av1_read_increment(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                                  uint32_t range_min, uint32_t range_max,
+                                  const char *name, uint32_t *write_to)
+{
+    uint32_t value;
+    int position, i;
+    char bits[33];
+
+    av_assert0(range_min <= range_max && range_max - range_min < sizeof(bits) - 1);
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    for (i = 0, value = range_min; value < range_max;) {
+        if (get_bits_left(gbc) < 1) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid increment value at "
+                   "%s: bitstream ended.\n", name);
+            return AVERROR_INVALIDDATA;
+        }
+        if (get_bits1(gbc)) {
+            bits[i++] = '1';
+            ++value;
+        } else {
+            bits[i++] = '0';
+            break;
+        }
+    }
+
+    if (ctx->trace_enable) {
+        bits[i] = 0;
+        ff_cbs_trace_syntax_element(ctx, position,
+                                    name, NULL, bits, value);
+    }
+
+    *write_to = value;
+    return 0;
+}
+
+static int cbs_av1_write_increment(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                                   uint32_t range_min, uint32_t range_max,
+                                   const char *name, uint32_t value)
+{
+    int len;
+
+    av_assert0(range_min <= range_max && range_max - range_min < 32);
+    if (value < range_min || value > range_max) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+               "%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
+               name, value, range_min, range_max);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (value == range_max)
+        len = range_max - range_min;
+    else
+        len = value - range_min + 1;
+    if (put_bits_left(pbc) < len)
+        return AVERROR(ENOSPC);
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (i = 0; i < len; i++) {
+            if (range_min + i == value)
+                bits[i] = '0';
+            else
+                bits[i] = '1';
+        }
+        bits[i] = 0;
+        ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
+                                    name, NULL, bits, value);
+    }
+
+    if (len > 0)
+        put_bits(pbc, len, (1 << len) - 1 - (value != range_max));
+
+    return 0;
+}
+
+static int cbs_av1_read_subexp(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                               uint32_t range_max, const char *name,
+                               const int *subscripts, uint32_t *write_to)
+{
+    uint32_t value;
+    int position, err;
+    uint32_t max_len, len, range_offset, range_bits;
+
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    av_assert0(range_max > 0);
+    max_len = av_log2(range_max - 1) - 3;
+
+    err = cbs_av1_read_increment(ctx, gbc, 0, max_len,
+                                 "subexp_more_bits", &len);
+    if (err < 0)
+        return err;
+
+    if (len) {
+        range_bits   = 2 + len;
+        range_offset = 1 << range_bits;
+    } else {
+        range_bits   = 3;
+        range_offset = 0;
+    }
+
+    if (len < max_len) {
+        err = ff_cbs_read_unsigned(ctx, gbc, range_bits,
+                                   "subexp_bits", NULL, &value,
+                                   0, MAX_UINT_BITS(range_bits));
+        if (err < 0)
+            return err;
+
+    } else {
+        err = cbs_av1_read_ns(ctx, gbc, range_max - range_offset,
+                              "subexp_final_bits", NULL, &value);
+        if (err < 0)
+            return err;
+    }
+    value += range_offset;
+
+    if (ctx->trace_enable)
+        ff_cbs_trace_syntax_element(ctx, position,
+                                    name, subscripts, "", value);
+
+    *write_to = value;
+    return err;
+}
+
+static int cbs_av1_write_subexp(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                                uint32_t range_max, const char *name,
+                                const int *subscripts, uint32_t value)
+{
+    int position, err;
+    uint32_t max_len, len, range_offset, range_bits;
+
+    if (value > range_max) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+               "%"PRIu32", but must be in [0,%"PRIu32"].\n",
+               name, value, range_max);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (ctx->trace_enable)
+        position = put_bits_count(pbc);
+
+    av_assert0(range_max > 0);
+    max_len = av_log2(range_max - 1) - 3;
+
+    if (value < 8) {
+        range_bits   = 3;
+        range_offset = 0;
+        len = 0;
+    } else {
+        range_bits = av_log2(value);
+        len = range_bits - 2;
+        if (len > max_len) {
+            // The top bin is combined with the one below it.
+            av_assert0(len == max_len + 1);
+            --range_bits;
+            len = max_len;
+        }
+        range_offset = 1 << range_bits;
+    }
+
+    err = cbs_av1_write_increment(ctx, pbc, 0, max_len,
+                                  "subexp_more_bits", len);
+    if (err < 0)
+        return err;
+
+    if (len < max_len) {
+        err = ff_cbs_write_unsigned(ctx, pbc, range_bits,
+                                    "subexp_bits", NULL,
+                                    value - range_offset,
+                                    0, MAX_UINT_BITS(range_bits));
+        if (err < 0)
+            return err;
+
+    } else {
+        err = cbs_av1_write_ns(ctx, pbc, range_max - range_offset,
+                               "subexp_final_bits", NULL,
+                               value - range_offset);
+        if (err < 0)
+            return err;
+    }
+
+    if (ctx->trace_enable)
+        ff_cbs_trace_syntax_element(ctx, position,
+                                    name, subscripts, "", value);
+
+    return err;
+}
+
+
+static int cbs_av1_tile_log2(int blksize, int target)
+{
+    int k;
+    for (k = 0; (blksize << k) < target; k++);
+    return k;
+}
+
+static int cbs_av1_get_relative_dist(const AV1RawSequenceHeader *seq,
+                                     unsigned int a, unsigned int b)
+{
+    unsigned int diff, m;
+    if (!seq->enable_order_hint)
+        return 0;
+    diff = a - b;
+    m = 1 << seq->order_hint_bits_minus_1;
+    diff = (diff & (m - 1)) - (diff & m);
+    return diff;
+}
+
+
+#define HEADER(name) do { \
+        ff_cbs_trace_header(ctx, name); \
+    } while (0)
+
+#define CHECK(call) do { \
+        err = (call); \
+        if (err < 0) \
+            return err; \
+    } while (0)
+
+#define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name
+#define FUNC_AV1(rw, name) FUNC_NAME(rw, av1, name)
+#define FUNC(name) FUNC_AV1(READWRITE, name)
+
+#define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]){ subs, __VA_ARGS__ }) : NULL)
+
+#define fb(width, name) \
+        xf(width, name, current->name, 0, MAX_UINT_BITS(width), 0)
+#define fc(width, name, range_min, range_max) \
+        xf(width, name, current->name, range_min, range_max, 0)
+#define flag(name) fb(1, name)
+#define su(width, name) \
+        xsu(width, name, current->name, 0)
+
+#define fbs(width, name, subs, ...) \
+        xf(width, name, current->name, 0, MAX_UINT_BITS(width), subs, __VA_ARGS__)
+#define fcs(width, name, range_min, range_max, subs, ...) \
+        xf(width, name, current->name, range_min, range_max, subs, __VA_ARGS__)
+#define flags(name, subs, ...) \
+        xf(1, name, current->name, 0, 1, subs, __VA_ARGS__)
+#define sus(width, name, subs, ...) \
+        xsu(width, name, current->name, subs, __VA_ARGS__)
+
+#define fixed(width, name, value) do { \
+        av_unused uint32_t fixed_value = value; \
+        xf(width, name, fixed_value, value, value, 0); \
+    } while (0)
+
+
+#define READ
+#define READWRITE read
+#define RWContext GetBitContext
+
+#define xf(width, name, var, range_min, range_max, subs, ...) do { \
+        uint32_t value = range_min; \
+        CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
+                                   SUBSCRIPTS(subs, __VA_ARGS__), \
+                                   &value, range_min, range_max)); \
+        var = value; \
+    } while (0)
+
+#define xsu(width, name, var, subs, ...) do { \
+        int32_t value = 0; \
+        CHECK(cbs_av1_read_su(ctx, rw, width, #name, \
+                              SUBSCRIPTS(subs, __VA_ARGS__), &value)); \
+        var = value; \
+    } while (0)
+
+#define uvlc(name, range_min, range_max) do { \
+        uint32_t value = range_min; \
+        CHECK(cbs_av1_read_uvlc(ctx, rw, #name, \
+                                &value, range_min, range_max)); \
+        current->name = value; \
+    } while (0)
+
+#define ns(max_value, name, subs, ...) do { \
+        uint32_t value = 0; \
+        CHECK(cbs_av1_read_ns(ctx, rw, max_value, #name, \
+                              SUBSCRIPTS(subs, __VA_ARGS__), &value)); \
+        current->name = value; \
+    } while (0)
+
+#define increment(name, min, max) do { \
+        uint32_t value = 0; \
+        CHECK(cbs_av1_read_increment(ctx, rw, min, max, #name, &value)); \
+        current->name = value; \
+    } while (0)
+
+#define subexp(name, max, subs, ...) do { \
+        uint32_t value = 0; \
+        CHECK(cbs_av1_read_subexp(ctx, rw, max, #name, \
+                                  SUBSCRIPTS(subs, __VA_ARGS__), &value)); \
+        current->name = value; \
+    } while (0)
+
+#define delta_q(name) do { \
+        uint8_t delta_coded; \
+        int8_t delta_q; \
+        xf(1, name.delta_coded, delta_coded, 0, 1, 0); \
+        if (delta_coded) \
+            xsu(1 + 6, name.delta_q, delta_q, 0); \
+        else \
+            delta_q = 0; \
+        current->name = delta_q; \
+    } while (0)
+
+#define leb128(name) do { \
+        uint64_t value = 0; \
+        CHECK(cbs_av1_read_leb128(ctx, rw, #name, &value)); \
+        current->name = value; \
+    } while (0)
+
+#define infer(name, value) do { \
+        current->name = value; \
+    } while (0)
+
+#define byte_alignment(rw) (get_bits_count(rw) % 8)
+
+#include "cbs_av1_syntax_template.c"
+
+#undef READ
+#undef READWRITE
+#undef RWContext
+#undef xf
+#undef xsu
+#undef uvlc
+#undef leb128
+#undef ns
+#undef increment
+#undef subexp
+#undef delta_q
+#undef leb128
+#undef infer
+#undef byte_alignment
+
+
+#define WRITE
+#define READWRITE write
+#define RWContext PutBitContext
+
+#define xf(width, name, var, range_min, range_max, subs, ...) do { \
+        CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
+                                    SUBSCRIPTS(subs, __VA_ARGS__), \
+                                    var, range_min, range_max)); \
+    } while (0)
+
+#define xsu(width, name, var, subs, ...) do { \
+        CHECK(cbs_av1_write_su(ctx, rw, width, #name, \
+                               SUBSCRIPTS(subs, __VA_ARGS__), var)); \
+    } while (0)
+
+#define uvlc(name, range_min, range_max) do { \
+        CHECK(cbs_av1_write_uvlc(ctx, rw, #name, current->name, \
+                                 range_min, range_max)); \
+    } while (0)
+
+#define ns(max_value, name, subs, ...) do { \
+        CHECK(cbs_av1_write_ns(ctx, rw, max_value, #name, \
+                               SUBSCRIPTS(subs, __VA_ARGS__), \
+                               current->name)); \
+    } while (0)
+
+#define increment(name, min, max) do { \
+        CHECK(cbs_av1_write_increment(ctx, rw, min, max, #name, \
+                                      current->name)); \
+    } while (0)
+
+#define subexp(name, max, subs, ...) do { \
+        CHECK(cbs_av1_write_subexp(ctx, rw, max, #name, \
+                                   SUBSCRIPTS(subs, __VA_ARGS__), \
+                                   current->name)); \
+    } while (0)
+
+#define delta_q(name) do { \
+        xf(1, name.delta_coded, current->name != 0, 0, 1, 0); \
+        if (current->name) \
+            xsu(1 + 6, name.delta_q, current->name, 0); \
+    } while (0)
+
+#define leb128(name) do { \
+        CHECK(cbs_av1_write_leb128(ctx, rw, #name, current->name)); \
+    } while (0)
+
+#define infer(name, value) do { \
+        if (current->name != (value)) { \
+            av_log(ctx->log_ctx, AV_LOG_WARNING, "Warning: " \
+                   "%s does not match inferred value: " \
+                   "%"PRId64", but should be %"PRId64".\n", \
+                   #name, (int64_t)current->name, (int64_t)(value)); \
+        } \
+    } while (0)
+
+#define byte_alignment(rw) (put_bits_count(rw) % 8)
+
+#include "cbs_av1_syntax_template.c"
+
+#undef READ
+#undef READWRITE
+#undef RWContext
+#undef xf
+#undef xsu
+#undef uvlc
+#undef leb128
+#undef ns
+#undef increment
+#undef subexp
+#undef delta_q
+#undef infer
+#undef byte_alignment
+
+
+static int cbs_av1_split_fragment(CodedBitstreamContext *ctx,
+                                  CodedBitstreamFragment *frag,
+                                  int header)
+{
+    GetBitContext gbc;
+    uint8_t *data;
+    size_t size;
+    uint64_t obu_length;
+    int pos, err, trace;
+
+    // Don't include this parsing in trace output.
+    trace = ctx->trace_enable;
+    ctx->trace_enable = 0;
+
+    data = frag->data;
+    size = frag->data_size;
+
+    if (INT_MAX / 8 < size) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid fragment: "
+               "too large (%zu bytes).\n", size);
+        err = AVERROR_INVALIDDATA;
+        goto fail;
+    }
+
+    while (size > 0) {
+        AV1RawOBUHeader header;
+        uint64_t obu_size;
+
+        init_get_bits(&gbc, data, 8 * size);
+
+        err = cbs_av1_read_obu_header(ctx, &gbc, &header);
+        if (err < 0)
+            goto fail;
+
+        if (!header.obu_has_size_field) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid OBU for raw "
+                   "stream: size field must be present.\n");
+            err = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        if (get_bits_left(&gbc) < 8) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid OBU: fragment "
+                   "too short (%zu bytes).\n", size);
+            err = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        err = cbs_av1_read_leb128(ctx, &gbc, "obu_size", &obu_size);
+        if (err < 0)
+            goto fail;
+
+        pos = get_bits_count(&gbc);
+        av_assert0(pos % 8 == 0 && pos / 8 <= size);
+
+        obu_length = pos / 8 + obu_size;
+
+        if (size < obu_length) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid OBU length: "
+                   "%"PRIu64", but only %zu bytes remaining in fragment.\n",
+                   obu_length, size);
+            err = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        err = ff_cbs_insert_unit_data(ctx, frag, -1, header.obu_type,
+                                      data, obu_length, frag->data_ref);
+        if (err < 0)
+            goto fail;
+
+        data += obu_length;
+        size -= obu_length;
+    }
+
+    err = 0;
+fail:
+    ctx->trace_enable = trace;
+    return err;
+}
+
+static void cbs_av1_free_tile_data(AV1RawTileData *td)
+{
+    av_buffer_unref(&td->data_ref);
+}
+
+static void cbs_av1_free_metadata(AV1RawMetadata *md)
+{
+    switch (md->metadata_type) {
+    case AV1_METADATA_TYPE_ITUT_T35:
+        av_buffer_unref(&md->metadata.itut_t35.payload_ref);
+        break;
+    }
+}
+
+static void cbs_av1_free_obu(void *unit, uint8_t *content)
+{
+    AV1RawOBU *obu = (AV1RawOBU*)content;
+
+    switch (obu->header.obu_type) {
+    case AV1_OBU_TILE_GROUP:
+        cbs_av1_free_tile_data(&obu->obu.tile_group.tile_data);
+        break;
+    case AV1_OBU_FRAME:
+        cbs_av1_free_tile_data(&obu->obu.frame.tile_group.tile_data);
+        break;
+    case AV1_OBU_TILE_LIST:
+        cbs_av1_free_tile_data(&obu->obu.tile_list.tile_data);
+        break;
+    case AV1_OBU_METADATA:
+        cbs_av1_free_metadata(&obu->obu.metadata);
+        break;
+    }
+
+    av_freep(&obu);
+}
+
+static int cbs_av1_ref_tile_data(CodedBitstreamContext *ctx,
+                                 CodedBitstreamUnit *unit,
+                                 GetBitContext *gbc,
+                                 AV1RawTileData *td)
+{
+    int pos;
+
+    pos = get_bits_count(gbc);
+    if (pos >= 8 * unit->data_size) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "Bitstream ended before "
+               "any data in tile group (%d bits read).\n", pos);
+        return AVERROR_INVALIDDATA;
+    }
+    // Must be byte-aligned at this point.
+    av_assert0(pos % 8 == 0);
+
+    td->data_ref = av_buffer_ref(unit->data_ref);
+    if (!td->data_ref)
+        return AVERROR(ENOMEM);
+
+    td->data      = unit->data      + pos / 8;
+    td->data_size = unit->data_size - pos / 8;
+
+    return 0;
+}
+
+static int cbs_av1_read_unit(CodedBitstreamContext *ctx,
+                             CodedBitstreamUnit *unit)
+{
+    CodedBitstreamAV1Context *priv = ctx->priv_data;
+    AV1RawOBU *obu;
+    GetBitContext gbc;
+    int err, start_pos, end_pos;
+
+    err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*obu),
+                                    &cbs_av1_free_obu);
+    if (err < 0)
+        return err;
+    obu = unit->content;
+
+    err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
+    if (err < 0)
+        return err;
+
+    err = cbs_av1_read_obu_header(ctx, &gbc, &obu->header);
+    if (err < 0)
+        return err;
+    av_assert0(obu->header.obu_type == unit->type);
+
+    if (obu->header.obu_has_size_field) {
+        uint64_t obu_size;
+        err = cbs_av1_read_leb128(ctx, &gbc, "obu_size", &obu_size);
+        if (err < 0)
+            return err;
+        obu->obu_size = obu_size;
+    } else {
+        if (unit->data_size < 1 + obu->header.obu_extension_flag) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid OBU length: "
+                   "unit too short (%zu).\n", unit->data_size);
+            return AVERROR_INVALIDDATA;
+        }
+        obu->obu_size = unit->data_size - 1 - obu->header.obu_extension_flag;
+    }
+
+    start_pos = get_bits_count(&gbc);
+
+    if (obu->header.obu_extension_flag) {
+        priv->temporal_id = obu->header.temporal_id;
+        priv->spatial_id  = obu->header.temporal_id;
+
+        if (obu->header.obu_type != AV1_OBU_SEQUENCE_HEADER &&
+            obu->header.obu_type != AV1_OBU_TEMPORAL_DELIMITER &&
+            priv->operating_point_idc) {
+            int in_temporal_layer =
+                (priv->operating_point_idc >>  priv->temporal_id    ) & 1;
+            int in_spatial_layer  =
+                (priv->operating_point_idc >> (priv->spatial_id + 8)) & 1;
+            if (!in_temporal_layer || !in_spatial_layer) {
+                // Decoding will drop this OBU at this operating point.
+            }
+        }
+    } else {
+        priv->temporal_id = 0;
+        priv->spatial_id  = 0;
+    }
+
+    switch (obu->header.obu_type) {
+    case AV1_OBU_SEQUENCE_HEADER:
+        {
+            err = cbs_av1_read_sequence_header_obu(ctx, &gbc,
+                                                   &obu->obu.sequence_header);
+            if (err < 0)
+                return err;
+
+            av_buffer_unref(&priv->sequence_header_ref);
+            priv->sequence_header = NULL;
+
+            priv->sequence_header_ref = av_buffer_ref(unit->content_ref);
+            if (!priv->sequence_header_ref)
+                return AVERROR(ENOMEM);
+            priv->sequence_header = &obu->obu.sequence_header;
+        }
+        break;
+    case AV1_OBU_TEMPORAL_DELIMITER:
+        {
+            err = cbs_av1_read_temporal_delimiter_obu(ctx, &gbc);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_FRAME_HEADER:
+    case AV1_OBU_REDUNDANT_FRAME_HEADER:
+        {
+            err = cbs_av1_read_frame_header_obu(ctx, &gbc,
+                                                &obu->obu.frame_header);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_TILE_GROUP:
+        {
+            err = cbs_av1_read_tile_group_obu(ctx, &gbc,
+                                              &obu->obu.tile_group);
+            if (err < 0)
+                return err;
+
+            err = cbs_av1_ref_tile_data(ctx, unit, &gbc,
+                                        &obu->obu.tile_group.tile_data);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_FRAME:
+        {
+            err = cbs_av1_read_frame_obu(ctx, &gbc, &obu->obu.frame);
+            if (err < 0)
+                return err;
+
+            err = cbs_av1_ref_tile_data(ctx, unit, &gbc,
+                                        &obu->obu.frame.tile_group.tile_data);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_TILE_LIST:
+        {
+            err = cbs_av1_read_tile_list_obu(ctx, &gbc,
+                                             &obu->obu.tile_list);
+            if (err < 0)
+                return err;
+
+            err = cbs_av1_ref_tile_data(ctx, unit, &gbc,
+                                        &obu->obu.tile_list.tile_data);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_METADATA:
+        {
+            err = cbs_av1_read_metadata_obu(ctx, &gbc, &obu->obu.metadata);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_PADDING:
+    default:
+        return AVERROR(ENOSYS);
+    }
+
+    end_pos = get_bits_count(&gbc);
+    av_assert0(end_pos <= unit->data_size * 8);
+
+    if (obu->obu_size > 0 &&
+        obu->header.obu_type != AV1_OBU_TILE_GROUP &&
+        obu->header.obu_type != AV1_OBU_FRAME) {
+        err = cbs_av1_read_trailing_bits(ctx, &gbc,
+                                         obu->obu_size * 8 + start_pos - end_pos);
+        if (err < 0)
+            return err;
+    }
+
+    return 0;
+}
+
+static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
+                             CodedBitstreamUnit *unit,
+                             PutBitContext *pbc)
+{
+    CodedBitstreamAV1Context *priv = ctx->priv_data;
+    AV1RawOBU *obu = unit->content;
+    PutBitContext pbc_tmp;
+    AV1RawTileData *td;
+    size_t header_size;
+    int err, start_pos, end_pos, data_pos;
+
+    // OBUs in the normal bitstream format must contain a size field
+    // in every OBU (in annex B it is optional, but we don't support
+    // writing that).
+    obu->header.obu_has_size_field = 1;
+
+    err = cbs_av1_write_obu_header(ctx, pbc, &obu->header);
+    if (err < 0)
+        return err;
+
+    if (obu->header.obu_has_size_field) {
+        pbc_tmp = *pbc;
+        // Add space for the size field to fill later.
+        put_bits32(pbc, 0);
+        put_bits32(pbc, 0);
+    }
+
+    td = NULL;
+    start_pos = put_bits_count(pbc);
+
+    switch (obu->header.obu_type) {
+    case AV1_OBU_SEQUENCE_HEADER:
+        {
+            err = cbs_av1_write_sequence_header_obu(ctx, pbc,
+                                                    &obu->obu.sequence_header);
+            if (err < 0)
+                return err;
+
+            av_buffer_unref(&priv->sequence_header_ref);
+            priv->sequence_header = NULL;
+
+            priv->sequence_header_ref = av_buffer_ref(unit->content_ref);
+            if (!priv->sequence_header_ref)
+                return AVERROR(ENOMEM);
+            priv->sequence_header = &obu->obu.sequence_header;
+        }
+        break;
+    case AV1_OBU_TEMPORAL_DELIMITER:
+        {
+            err = cbs_av1_write_temporal_delimiter_obu(ctx, pbc);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_FRAME_HEADER:
+    case AV1_OBU_REDUNDANT_FRAME_HEADER:
+        {
+            err = cbs_av1_write_frame_header_obu(ctx, pbc,
+                                                 &obu->obu.frame_header);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_TILE_GROUP:
+        {
+            err = cbs_av1_write_tile_group_obu(ctx, pbc,
+                                               &obu->obu.tile_group);
+            if (err < 0)
+                return err;
+
+            td = &obu->obu.tile_group.tile_data;
+        }
+        break;
+    case AV1_OBU_FRAME:
+        {
+            err = cbs_av1_write_frame_obu(ctx, pbc, &obu->obu.frame);
+            if (err < 0)
+                return err;
+
+            td = &obu->obu.frame.tile_group.tile_data;
+        }
+        break;
+    case AV1_OBU_TILE_LIST:
+        {
+            err = cbs_av1_write_tile_list_obu(ctx, pbc, &obu->obu.tile_list);
+            if (err < 0)
+                return err;
+
+            td = &obu->obu.tile_list.tile_data;
+        }
+        break;
+    case AV1_OBU_METADATA:
+        {
+            err = cbs_av1_write_metadata_obu(ctx, pbc, &obu->obu.metadata);
+            if (err < 0)
+                return err;
+        }
+        break;
+    case AV1_OBU_PADDING:
+    default:
+        return AVERROR(ENOSYS);
+    }
+
+    end_pos = put_bits_count(pbc);
+    header_size = (end_pos - start_pos + 7) / 8;
+    if (td) {
+        obu->obu_size = header_size + td->data_size;
+    } else if (header_size > 0) {
+        // Add trailing bits and recalculate.
+        err = cbs_av1_write_trailing_bits(ctx, pbc, 8 - end_pos % 8);
+        if (err < 0)
+            return err;
+        end_pos = put_bits_count(pbc);
+        obu->obu_size = (end_pos - start_pos + 7) / 8;
+    } else {
+        // Empty OBU.
+        obu->obu_size = 0;
+    }
+
+    end_pos = put_bits_count(pbc);
+    // Must now be byte-aligned.
+    av_assert0(end_pos % 8 == 0);
+    flush_put_bits(pbc);
+    start_pos /= 8;
+    end_pos   /= 8;
+
+    *pbc = pbc_tmp;
+    err = cbs_av1_write_leb128(ctx, pbc, "obu_size", obu->obu_size);
+    if (err < 0)
+        return err;
+
+    data_pos = put_bits_count(pbc) / 8;
+    flush_put_bits(pbc);
+    av_assert0(data_pos <= start_pos);
+
+    if (8 * obu->obu_size > put_bits_left(pbc))
+        return AVERROR(ENOSPC);
+
+    if (obu->obu_size > 0) {
+        memmove(priv->write_buffer + data_pos,
+                priv->write_buffer + start_pos, header_size);
+        skip_put_bytes(pbc, header_size);
+
+        if (td) {
+            memcpy(priv->write_buffer + data_pos + header_size,
+                   td->data, td->data_size);
+            skip_put_bytes(pbc, td->data_size);
+        }
+    }
+
+    return 0;
+}
+
+static int cbs_av1_write_unit(CodedBitstreamContext *ctx,
+                              CodedBitstreamUnit *unit)
+{
+    CodedBitstreamAV1Context *priv = ctx->priv_data;
+    PutBitContext pbc;
+    int err;
+
+    if (!priv->write_buffer) {
+        // Initial write buffer size is 1MB.
+        priv->write_buffer_size = 1024 * 1024;
+
+    reallocate_and_try_again:
+        err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
+        if (err < 0) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
+                   "sufficiently large write buffer (last attempt "
+                   "%zu bytes).\n", priv->write_buffer_size);
+            return err;
+        }
+    }
+
+    init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size);
+
+    err = cbs_av1_write_obu(ctx, unit, &pbc);
+    if (err == AVERROR(ENOSPC)) {
+        // Overflow.
+        priv->write_buffer_size *= 2;
+        goto reallocate_and_try_again;
+    }
+    if (err < 0)
+        return err;
+
+    // Overflow but we didn't notice.
+    av_assert0(put_bits_count(&pbc) <= 8 * priv->write_buffer_size);
+
+    // OBU data must be byte-aligned.
+    av_assert0(put_bits_count(&pbc) % 8 == 0);
+
+    unit->data_size = put_bits_count(&pbc) / 8;
+    flush_put_bits(&pbc);
+
+    err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size);
+    if (err < 0)
+        return err;
+
+    memcpy(unit->data, priv->write_buffer, unit->data_size);
+
+    return 0;
+}
+
+static int cbs_av1_assemble_fragment(CodedBitstreamContext *ctx,
+                                     CodedBitstreamFragment *frag)
+{
+    size_t size, pos;
+    int i;
+
+    size = 0;
+    for (i = 0; i < frag->nb_units; i++)
+        size += frag->units[i].data_size;
+
+    frag->data_ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
+    if (!frag->data_ref)
+        return AVERROR(ENOMEM);
+    frag->data = frag->data_ref->data;
+    memset(frag->data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
+
+    pos = 0;
+    for (i = 0; i < frag->nb_units; i++) {
+        memcpy(frag->data + pos, frag->units[i].data,
+               frag->units[i].data_size);
+        pos += frag->units[i].data_size;
+    }
+    av_assert0(pos == size);
+    frag->data_size = size;
+
+    return 0;
+}
+
+static void cbs_av1_close(CodedBitstreamContext *ctx)
+{
+    CodedBitstreamAV1Context *priv = ctx->priv_data;
+
+    av_buffer_unref(&priv->sequence_header_ref);
+
+    av_freep(&priv->write_buffer);
+}
+
+const CodedBitstreamType ff_cbs_type_av1 = {
+    .codec_id          = AV_CODEC_ID_AV1,
+
+    .priv_data_size    = sizeof(CodedBitstreamAV1Context),
+
+    .split_fragment    = &cbs_av1_split_fragment,
+    .read_unit         = &cbs_av1_read_unit,
+    .write_unit        = &cbs_av1_write_unit,
+    .assemble_fragment = &cbs_av1_assemble_fragment,
+
+    .close             = &cbs_av1_close,
+};