[FFmpeg-devel] [PATCH 1/2] lavc: Add coded bitstream read/write support for VP9

Mark Thompson sw at jkqxz.net
Tue Apr 3 01:47:05 EEST 2018


---
Written a while ago but never sent, because it wasn't particularly useful beyond the learning exercise of writing it.  However, it does now have parts in common with AV1 where this will be more useful, so here we go.


 configure                            |   2 +
 libavcodec/Makefile                  |   1 +
 libavcodec/cbs.c                     |   6 +
 libavcodec/cbs_internal.h            |   1 +
 libavcodec/cbs_vp9.c                 | 657 +++++++++++++++++++++++++++++++++++
 libavcodec/cbs_vp9.h                 | 171 +++++++++
 libavcodec/cbs_vp9_syntax_template.c | 388 +++++++++++++++++++++
 7 files changed, 1226 insertions(+)
 create mode 100644 libavcodec/cbs_vp9.c
 create mode 100644 libavcodec/cbs_vp9.h
 create mode 100644 libavcodec/cbs_vp9_syntax_template.c

diff --git a/configure b/configure
index 08d6fc5983..890de64ab4 100755
--- a/configure
+++ b/configure
@@ -2235,6 +2235,7 @@ CONFIG_EXTRA="
     cbs_h264
     cbs_h265
     cbs_mpeg2
+    cbs_vp9
     dirac_parse
     dvprofile
     exif
@@ -2494,6 +2495,7 @@ threads_if_any="$THREADS_LIST"
 cbs_h264_select="cbs golomb"
 cbs_h265_select="cbs golomb"
 cbs_mpeg2_select="cbs"
+cbs_vp9_select="cbs"
 dct_select="rdft"
 dirac_parse_select="golomb"
 error_resilience_select="me_cmp"
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 4b8ad121db..6ee16d855b 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -65,6 +65,7 @@ OBJS-$(CONFIG_CBS)                     += cbs.o
 OBJS-$(CONFIG_CBS_H264)                += cbs_h2645.o h2645_parse.o
 OBJS-$(CONFIG_CBS_H265)                += cbs_h2645.o h2645_parse.o
 OBJS-$(CONFIG_CBS_MPEG2)               += cbs_mpeg2.o
+OBJS-$(CONFIG_CBS_VP9)                 += cbs_vp9.o
 OBJS-$(CONFIG_CRYSTALHD)               += crystalhd.o
 OBJS-$(CONFIG_DCT)                     += dct.o dct32_fixed.o dct32_float.o
 OBJS-$(CONFIG_ERROR_RESILIENCE)        += error_resilience.o
diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
index 897e0bb28e..740a51e3d4 100644
--- a/libavcodec/cbs.c
+++ b/libavcodec/cbs.c
@@ -38,6 +38,9 @@ static const CodedBitstreamType *cbs_type_table[] = {
 #if CONFIG_CBS_MPEG2
     &ff_cbs_type_mpeg2,
 #endif
+#if CONFIG_CBS_VP9
+    &ff_cbs_type_vp9,
+#endif
 };
 
 const enum AVCodecID ff_cbs_all_codec_ids[] = {
@@ -49,6 +52,9 @@ const enum AVCodecID ff_cbs_all_codec_ids[] = {
 #endif
 #if CONFIG_CBS_MPEG2
     AV_CODEC_ID_MPEG2VIDEO,
+#endif
+#if CONFIG_CBS_VP9
+    AV_CODEC_ID_VP9,
 #endif
     AV_CODEC_ID_NONE
 };
diff --git a/libavcodec/cbs_internal.h b/libavcodec/cbs_internal.h
index be540e2a44..0207e2aaa2 100644
--- a/libavcodec/cbs_internal.h
+++ b/libavcodec/cbs_internal.h
@@ -87,6 +87,7 @@ int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
 extern const CodedBitstreamType ff_cbs_type_h264;
 extern const CodedBitstreamType ff_cbs_type_h265;
 extern const CodedBitstreamType ff_cbs_type_mpeg2;
+extern const CodedBitstreamType ff_cbs_type_vp9;
 
 
 #endif /* AVCODEC_CBS_INTERNAL_H */
diff --git a/libavcodec/cbs_vp9.c b/libavcodec/cbs_vp9.c
new file mode 100644
index 0000000000..a38b97d863
--- /dev/null
+++ b/libavcodec/cbs_vp9.c
@@ -0,0 +1,657 @@
+/*
+ * 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 "cbs.h"
+#include "cbs_internal.h"
+#include "cbs_vp9.h"
+#include "internal.h"
+
+
+static int cbs_vp9_read_s(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                          int width, const char *name, int32_t *write_to)
+{
+    uint32_t magnitude;
+    int position, sign;
+    int32_t result;
+
+    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);
+    result    = 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, bits, result);
+    }
+
+    *write_to = result;
+    return 0;
+}
+
+static int cbs_vp9_write_s(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                           int width, const char *name, 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, bits, value);
+    }
+
+    put_bits(pbc, width, magnitude);
+    put_bits(pbc, 1, sign);
+
+    return 0;
+}
+
+static int cbs_vp9_read_increment(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                                  uint32_t range_min, uint32_t range_max,
+                                  const char *name, uint32_t *write_to)
+{
+    uint32_t result;
+    int position, i;
+    char bits[8];
+
+    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, result = range_min; result < 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';
+            ++result;
+        } else {
+            bits[i++] = '0';
+            break;
+        }
+    }
+
+    if (ctx->trace_enable) {
+        bits[i] = 0;
+        ff_cbs_trace_syntax_element(ctx, position, name, bits, result);
+    }
+
+    *write_to = result;
+    return 0;
+}
+
+static int cbs_vp9_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 < 8);
+    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[8];
+        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, bits, value);
+    }
+
+    if (len > 0)
+        put_bits(pbc, len, (1 << len) - 1 - (value != range_max));
+
+    return 0;
+}
+
+static int cbs_vp9_read_le(CodedBitstreamContext *ctx, GetBitContext *gbc,
+                           int width, const char *name, uint32_t *write_to)
+{
+    uint32_t result;
+    int position, b;
+
+    av_assert0(width % 8 == 0);
+
+    if (ctx->trace_enable)
+        position = get_bits_count(gbc);
+
+    result = 0;
+    for (b = 0; b < width; b += 8)
+        result |= get_bits(gbc, 8) << b;
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (b = 0; b < width; b += 8)
+            for (i = 0; i < 8; i++)
+                bits[b + i] = result >> (b + i) & 1 ? '1' : '0';
+        bits[b] = 0;
+
+        ff_cbs_trace_syntax_element(ctx, position, name, bits, result);
+    }
+
+    *write_to = result;
+    return 0;
+}
+
+static int cbs_vp9_write_le(CodedBitstreamContext *ctx, PutBitContext *pbc,
+                            int width, const char *name, uint32_t value)
+{
+    int b;
+
+    av_assert0(width % 8 == 0);
+
+    if (ctx->trace_enable) {
+        char bits[33];
+        int i;
+        for (b = 0; b < width; b += 8)
+            for (i = 0; i < 8; i++)
+                bits[b + i] = value >> (b + i) & 1 ? '1' : '0';
+        bits[b] = 0;
+
+        ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc), name, bits, value);
+    }
+
+    for (b = 0; b < width; b += 8)
+        put_bits(pbc, 8, value >> b & 0xff);
+
+    return 0;
+}
+
+#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_VP9(rw, name) FUNC_NAME(rw, vp9, name)
+#define FUNC(name) FUNC_VP9(READWRITE, name)
+
+
+#define READ
+#define READWRITE read
+#define RWContext GetBitContext
+
+#define xf(width, name, var) do { \
+        uint32_t value = 0; \
+        CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
+                                   &value, 0, (1 << width) - 1)); \
+        var = value; \
+    } while (0)
+#define xs(width, name, var) do { \
+        int32_t value = 0; \
+        CHECK(cbs_vp9_read_s(ctx, rw, width, #name, &value)); \
+        var = value; \
+    } while (0)
+
+#define f(width, name) \
+        xf(width, name, current->name)
+#define s(width, name) \
+        xs(width, name, current->name)
+
+#define increment(name, min, max) do { \
+        uint32_t value = 0; \
+        CHECK(cbs_vp9_read_increment(ctx, rw, min, max, #name, &value)); \
+        current->name = value; \
+    } while (0)
+
+#define fle(width, name) do { \
+        CHECK(cbs_vp9_read_le(ctx, rw, width, #name, &current->name)); \
+    } while (0)
+
+#define delta_q(name) do { \
+        uint8_t delta_coded; \
+        int8_t delta_q; \
+        xf(1, name.delta_coded, delta_coded); \
+        if (delta_coded) \
+            xs(4, name.delta_q, delta_q); \
+        else \
+            delta_q = 0; \
+        current->name = delta_q; \
+    } while (0)
+
+#define prob(name) do { \
+        uint8_t prob_coded; \
+        int8_t prob; \
+        xf(1, name.prob_coded, prob_coded); \
+        if (prob_coded) \
+            xf(8, name.prob, prob); \
+        else \
+            prob = 255; \
+        current->name = prob; \
+    } while (0)
+
+#define infer(name, value) do { \
+        current->name = value; \
+    } while (0)
+
+#define byte_alignment(rw) (get_bits_count(rw) % 8)
+
+#include "cbs_vp9_syntax_template.c"
+
+#undef READ
+#undef READWRITE
+#undef RWContext
+#undef xf
+#undef xs
+#undef f
+#undef s
+#undef increment
+#undef fle
+#undef delta_q
+#undef prob
+#undef infer
+#undef byte_alignment
+
+
+#define WRITE
+#define READWRITE write
+#define RWContext PutBitContext
+
+#define xf(width, name, var) do { \
+        CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
+                                    var, 0, (1 << width) - 1)); \
+    } while (0)
+#define xs(width, name, var) do { \
+        CHECK(cbs_vp9_write_s(ctx, rw, width, #name, var)); \
+    } while (0)
+
+#define f(width, name) \
+        xf(width, name, current->name)
+#define s(width, name) \
+        xs(width, name, current->name)
+
+#define increment(name, min, max) do { \
+        CHECK(cbs_vp9_write_increment(ctx, rw, min, max, #name, current->name)); \
+    } while (0)
+
+#define fle(width, name) do { \
+        CHECK(cbs_vp9_write_le(ctx, rw, width, #name, current->name)); \
+    } while (0)
+
+#define delta_q(name) do { \
+        xf(1, name.delta_coded, !!current->name); \
+        if (current->name) \
+            xs(4, name.delta_q, current->name); \
+    } while (0)
+
+#define prob(name) do { \
+        xf(1, name.prob_coded, current->name != 255); \
+        if (current->name != 255) \
+            xf(8, name.prob, 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_vp9_syntax_template.c"
+
+#undef READ
+#undef READWRITE
+#undef RWContext
+#undef xf
+#undef xs
+#undef f
+#undef s
+#undef increment
+#undef fle
+#undef delta_q
+#undef prob
+#undef infer
+#undef byte_alignment
+
+
+static int cbs_vp9_split_fragment(CodedBitstreamContext *ctx,
+                                  CodedBitstreamFragment *frag,
+                                  int header)
+{
+    uint8_t superframe_header;
+    int err;
+
+    // Last byte in the packet.
+    superframe_header = frag->data[frag->data_size - 1];
+
+    if ((superframe_header & 0xe0) == 0xc0) {
+        VP9RawSuperframeIndex sfi;
+        GetBitContext gbc;
+        size_t index_size, pos;
+        int i;
+
+        index_size = 2 + (((superframe_header & 0x18) >> 3) + 1) *
+                          ((superframe_header & 0x07) + 1);
+
+        err = init_get_bits(&gbc, frag->data + frag->data_size - index_size,
+                            8 * index_size);
+        if (err < 0)
+            return err;
+
+        err = cbs_vp9_read_superframe_index(ctx, &gbc, &sfi);
+        if (err < 0)
+            return err;
+
+        pos = 0;
+        for (i = 0; i <= sfi.frames_in_superframe_minus_1; i++) {
+            if (pos + sfi.frame_sizes[i] + index_size > frag->data_size) {
+                av_log(ctx->log_ctx, AV_LOG_ERROR, "Frame %d too large "
+                       "in superframe: %"PRIu32" bytes.\n",
+                       i, sfi.frame_sizes[i]);
+                return AVERROR_INVALIDDATA;
+            }
+
+            err = ff_cbs_insert_unit_data(ctx, frag, -1, 0,
+                                          frag->data + pos,
+                                          sfi.frame_sizes[i],
+                                          frag->data_ref);
+            if (err < 0)
+                return err;
+
+            pos += sfi.frame_sizes[i];
+        }
+        if (pos + index_size != frag->data_size) {
+            av_log(ctx->log_ctx, AV_LOG_WARNING, "Extra padding at "
+                   "end of superframe: %zu bytes.\n",
+                   frag->data_size - (pos + index_size));
+        }
+
+        return 0;
+
+    } else {
+        err = ff_cbs_insert_unit_data(ctx, frag, -1, 0,
+                                      frag->data, frag->data_size,
+                                      frag->data_ref);
+        if (err < 0)
+            return err;
+    }
+
+    return 0;
+}
+
+static void cbs_vp9_free_frame(void *unit, uint8_t *content)
+{
+    VP9RawFrame *frame = (VP9RawFrame*)content;
+    av_buffer_unref(&frame->data_ref);
+    av_freep(&frame);
+}
+
+static int cbs_vp9_read_unit(CodedBitstreamContext *ctx,
+                             CodedBitstreamUnit *unit)
+{
+    VP9RawFrame *frame;
+    GetBitContext gbc;
+    int err, pos;
+
+    err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
+    if (err < 0)
+        return err;
+
+    err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*frame),
+                                    &cbs_vp9_free_frame);
+    if (err < 0)
+        return err;
+    frame = unit->content;
+
+    err = cbs_vp9_read_frame(ctx, &gbc, frame);
+    if (err < 0)
+        return err;
+
+    pos = get_bits_count(&gbc);
+    av_assert0(pos % 8 == 0);
+    pos /= 8;
+    av_assert0(pos <= unit->data_size);
+
+    if (pos == unit->data_size) {
+        // No data (e.g. a show-existing-frame frame).
+    } else {
+        frame->data_ref = av_buffer_ref(unit->data_ref);
+        if (!frame->data_ref)
+            return AVERROR(ENOMEM);
+
+        frame->data      = unit->data      + pos;
+        frame->data_size = unit->data_size - pos;
+    }
+
+    return 0;
+}
+
+static int cbs_vp9_write_unit(CodedBitstreamContext *ctx,
+                              CodedBitstreamUnit *unit)
+{
+    CodedBitstreamVP9Context *priv = ctx->priv_data;
+    VP9RawFrame *frame = unit->content;
+    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_vp9_write_frame(ctx, &pbc, frame);
+    if (err == AVERROR(ENOSPC)) {
+        priv->write_buffer_size *= 2;
+        goto reallocate_and_try_again;
+    }
+    if (err < 0)
+        return err;
+
+    // Frame must be byte-aligned.
+    av_assert0(put_bits_count(&pbc) % 8 == 0);
+
+    unit->data_size        = put_bits_count(&pbc) / 8;
+    unit->data_bit_padding = 0;
+    flush_put_bits(&pbc);
+
+    if (frame->data) {
+        if (unit->data_size + frame->data_size >
+            priv->write_buffer_size) {
+            priv->write_buffer_size *= 2;
+            goto reallocate_and_try_again;
+        }
+
+        memcpy(priv->write_buffer + unit->data_size,
+               frame->data, frame->data_size);
+        unit->data_size += frame->data_size;
+    }
+
+    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_vp9_assemble_fragment(CodedBitstreamContext *ctx,
+                                     CodedBitstreamFragment *frag)
+{
+    int err;
+
+    if (frag->nb_units == 1) {
+        // Output is just the content of the single frame.
+
+        CodedBitstreamUnit *frame = &frag->units[0];
+
+        frag->data_ref = av_buffer_ref(frame->data_ref);
+        if (!frag->data_ref)
+            return AVERROR(ENOMEM);
+
+        frag->data      = frame->data;
+        frag->data_size = frame->data_size;
+
+    } else {
+        // Build superframe out of frames.
+
+        VP9RawSuperframeIndex sfi;
+        PutBitContext pbc;
+        AVBufferRef *ref;
+        uint8_t *data;
+        size_t size, max, pos;
+        int i, size_len;
+
+        if (frag->nb_units > 8) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Too many frames to "
+                   "make superframe: %d.\n", frag->nb_units);
+            return AVERROR(EINVAL);
+        }
+
+        max = 0;
+        for (i = 0; i < frag->nb_units; i++)
+            if (max < frag->units[i].data_size)
+                max = frag->units[i].data_size;
+
+        if (max < 2)
+            size_len = 1;
+        else
+            size_len = (av_log2(max) + 7) / 8;
+        av_assert0(size_len <= 4);
+
+        sfi.superframe_marker            = VP9_SUPERFRAME_MARKER;
+        sfi.bytes_per_framesize_minus_1  = size_len - 1;
+        sfi.frames_in_superframe_minus_1 = frag->nb_units - 1;
+
+        size = 2;
+        for (i = 0; i < frag->nb_units; i++) {
+            size += size_len + frag->units[i].data_size;
+            sfi.frame_sizes[i] = frag->units[i].data_size;
+        }
+
+        ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
+        if (!ref)
+            return AVERROR(ENOMEM);
+        data = ref->data;
+        memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
+
+        pos = 0;
+        for (i = 0; i < frag->nb_units; i++) {
+            av_assert0(size - pos > frag->units[i].data_size);
+            memcpy(data + pos, frag->units[i].data,
+                   frag->units[i].data_size);
+            pos += frag->units[i].data_size;
+        }
+        av_assert0(size - pos == 2 + frag->nb_units * size_len);
+
+        init_put_bits(&pbc, data + pos, size - pos);
+
+        err = cbs_vp9_write_superframe_index(ctx, &pbc, &sfi);
+        if (err < 0) {
+            av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to write "
+                   "superframe index.\n");
+            av_buffer_unref(&ref);
+            return err;
+        }
+
+        av_assert0(put_bits_left(&pbc) == 0);
+        flush_put_bits(&pbc);
+
+        frag->data_ref  = ref;
+        frag->data      = data;
+        frag->data_size = size;
+    }
+
+    return 0;
+}
+
+static void cbs_vp9_close(CodedBitstreamContext *ctx)
+{
+    CodedBitstreamVP9Context *priv = ctx->priv_data;
+
+    av_freep(&priv->write_buffer);
+}
+
+const CodedBitstreamType ff_cbs_type_vp9 = {
+    .codec_id          = AV_CODEC_ID_VP9,
+
+    .priv_data_size    = sizeof(CodedBitstreamVP9Context),
+
+    .split_fragment    = &cbs_vp9_split_fragment,
+    .read_unit         = &cbs_vp9_read_unit,
+    .write_unit        = &cbs_vp9_write_unit,
+    .assemble_fragment = &cbs_vp9_assemble_fragment,
+
+    .close             = &cbs_vp9_close,
+};
diff --git a/libavcodec/cbs_vp9.h b/libavcodec/cbs_vp9.h
new file mode 100644
index 0000000000..7a70a1e41a
--- /dev/null
+++ b/libavcodec/cbs_vp9.h
@@ -0,0 +1,171 @@
+/*
+ * 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
+ */
+
+#ifndef AVCODEC_CBS_VP9_H
+#define AVCODEC_CBS_VP9_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "cbs.h"
+
+
+enum {
+    VP9_MAX_SEGMENTS = 8,
+    VP9_SEG_LVL_MAX  = 4,
+    VP9_MIN_TILE_WIDTH_B64 = 4,
+    VP9_MAX_TILE_WIDTH_B64 = 64,
+
+    VP9_FRAME_SYNC_0 = 0x49,
+    VP9_FRAME_SYNC_1 = 0x83,
+    VP9_FRAME_SYNC_2 = 0x42,
+
+    VP9_SUPERFRAME_MARKER = 6,
+};
+
+enum {
+    VP9_CS_UNKNOWN   = 0,
+    VP9_CS_BT_601    = 1,
+    VP9_CS_BT_709    = 2,
+    VP9_CS_SMPTE_170 = 3,
+    VP9_CS_SMPTE_240 = 4,
+    VP9_CS_BT_2020   = 5,
+    VP9_CS_RESERVED  = 6,
+    VP9_CS_RGB       = 7,
+};
+
+
+typedef struct VP9RawFrameHeader {
+    uint8_t frame_marker;
+    uint8_t profile_low_bit;
+    uint8_t profile_high_bit;
+    uint8_t profile_reserved_zero;
+
+    uint8_t show_existing_frame;
+    uint8_t frame_to_show_map_idx;
+
+    uint8_t frame_type;
+    uint8_t show_frame;
+    uint8_t error_resilient_mode;
+
+    // Color config.
+    uint8_t ten_or_twelve_bit;
+    uint8_t color_space;
+    uint8_t color_range;
+    uint8_t subsampling_x;
+    uint8_t subsampling_y;
+    uint8_t color_config_reserved_zero;
+
+    uint8_t refresh_frame_flags;
+
+    uint8_t intra_only;
+    uint8_t reset_frame_context;
+
+    uint8_t ref_frame_idx[3];
+    uint8_t ref_frame_sign_bias[3];
+
+    uint8_t allow_high_precision_mv;
+
+    uint8_t refresh_frame_context;
+    uint8_t frame_parallel_decoding_mode;
+
+    uint8_t frame_context_idx;
+
+    // Frame/render size.
+    uint8_t found_ref[3];
+    uint16_t frame_width_minus_1;
+    uint16_t frame_height_minus_1;
+    uint8_t render_and_frame_size_different;
+    uint16_t render_width_minus_1;
+    uint16_t render_height_minus_1;
+
+    // Interpolation filter.
+    uint8_t is_filter_switchable;
+    uint8_t raw_interpolation_filter_type;
+
+    // Loop filter params.
+    uint8_t loop_filter_level;
+    uint8_t loop_filter_sharpness;
+    uint8_t loop_filter_delta_enabled;
+    uint8_t loop_filter_delta_update;
+    uint8_t update_ref_delta[4];
+    int8_t loop_filter_ref_deltas[4];
+    uint8_t update_mode_delta[2];
+    int8_t loop_filter_mode_deltas[2];
+
+    // Quantization params.
+    uint8_t base_q_idx;
+    uint8_t delta_q_y_dc;
+    uint8_t delta_q_uv_dc;
+    uint8_t delta_q_uv_ac;
+
+    // Segmentation params.
+    uint8_t segmentation_enabled;
+    uint8_t segmentation_update_map;
+    uint8_t segmentation_tree_probs[7];
+    uint8_t segmentation_temporal_update;
+    uint8_t segmentation_pred_prob[3];
+    uint8_t segmentation_update_data;
+    uint8_t segmentation_abs_or_delta_update;
+    uint8_t feature_enabled[8][4];
+    uint8_t feature_value[8][4];
+    uint8_t feature_sign[8][4];
+
+    // Tile info.
+    uint8_t tile_cols_log2;
+    uint8_t tile_rows_log2;
+
+    uint16_t header_size_in_bytes;
+} VP9RawFrameHeader;
+
+typedef struct VP9RawFrame {
+    VP9RawFrameHeader header;
+
+    uint8_t     *data;
+    size_t       data_size;
+    AVBufferRef *data_ref;
+} VP9RawFrame;
+
+typedef struct VP9RawSuperframeIndex {
+    uint8_t superframe_marker;
+    uint8_t bytes_per_framesize_minus_1;
+    uint8_t frames_in_superframe_minus_1;
+    uint32_t frame_sizes[8];
+} VP9RawSuperframeIndex;
+
+typedef struct VP9RawSuperframe {
+    VP9RawFrame frames[8];
+    VP9RawSuperframeIndex index;
+} VP9RawSuperframe;
+
+
+typedef struct CodedBitstreamVP9Context {
+    // Frame dimensions in 8x8 mode info blocks.
+    uint16_t mi_cols;
+    uint16_t mi_rows;
+    // Frame dimensions in 64x64 superblocks.
+    uint16_t sb64_cols;
+    uint16_t sb64_rows;
+
+    // Write buffer.
+    uint8_t *write_buffer;
+    size_t write_buffer_size;
+} CodedBitstreamVP9Context;
+
+
+#endif /* AVCODEC_CBS_VP9_H */
diff --git a/libavcodec/cbs_vp9_syntax_template.c b/libavcodec/cbs_vp9_syntax_template.c
new file mode 100644
index 0000000000..1803dbf73b
--- /dev/null
+++ b/libavcodec/cbs_vp9_syntax_template.c
@@ -0,0 +1,388 @@
+/*
+ * 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
+ */
+
+static int FUNC(frame_sync_code)(CodedBitstreamContext *ctx, RWContext *rw,
+                                 VP9RawFrameHeader *current)
+{
+    uint8_t frame_sync_byte_0 = VP9_FRAME_SYNC_0;
+    uint8_t frame_sync_byte_1 = VP9_FRAME_SYNC_1;
+    uint8_t frame_sync_byte_2 = VP9_FRAME_SYNC_2;
+    int err;
+
+    xf(8, frame_sync_byte_0, frame_sync_byte_0);
+    xf(8, frame_sync_byte_1, frame_sync_byte_1);
+    xf(8, frame_sync_byte_2, frame_sync_byte_2);
+
+    if (frame_sync_byte_0 != VP9_FRAME_SYNC_0 ||
+        frame_sync_byte_1 != VP9_FRAME_SYNC_1 ||
+        frame_sync_byte_2 != VP9_FRAME_SYNC_2) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid frame sync code: "
+               "%02x %02x %02x.\n", frame_sync_byte_0,
+               frame_sync_byte_1, frame_sync_byte_2);
+        return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
+
+static int FUNC(color_config)(CodedBitstreamContext *ctx, RWContext *rw,
+                              VP9RawFrameHeader *current, int profile)
+{
+    int err;
+
+    if (profile >= 2)
+        f(1, ten_or_twelve_bit);
+
+    f(3, color_space);
+
+    if (current->color_space != VP9_CS_RGB) {
+        f(1, color_range);
+        if (profile == 1 || profile == 3) {
+            f(1, subsampling_x);
+            f(1, subsampling_y);
+            f(1, color_config_reserved_zero);
+        } else {
+            infer(subsampling_x, 1);
+            infer(subsampling_y, 1);
+        }
+    } else {
+        infer(color_range, 1);
+        if (profile == 1 || profile == 3) {
+            infer(subsampling_x, 0);
+            infer(subsampling_y, 0);
+        }
+    }
+
+    return 0;
+}
+
+static int FUNC(frame_size)(CodedBitstreamContext *ctx, RWContext *rw,
+                            VP9RawFrameHeader *current)
+{
+    CodedBitstreamVP9Context *vp9 = ctx->priv_data;
+    int err;
+
+    f(16, frame_width_minus_1);
+    f(16, frame_height_minus_1);
+
+    vp9->mi_cols = (current->frame_width_minus_1  + 8) >> 3;
+    vp9->mi_rows = (current->frame_height_minus_1 + 8) >> 3;
+    vp9->sb64_cols = (vp9->mi_cols + 7) >> 3;
+    vp9->sb64_rows = (vp9->mi_rows + 7) >> 3;
+
+    return 0;
+}
+
+static int FUNC(render_size)(CodedBitstreamContext *ctx, RWContext *rw,
+                             VP9RawFrameHeader *current)
+{
+    int err;
+
+    f(1, render_and_frame_size_different);
+
+    if (current->render_and_frame_size_different) {
+        f(16, render_width_minus_1);
+        f(16, render_height_minus_1);
+    }
+
+    return 0;
+}
+
+static int FUNC(frame_size_with_refs)(CodedBitstreamContext *ctx, RWContext *rw,
+                                      VP9RawFrameHeader *current)
+{
+    int err, i;
+
+    for (i = 0; i < 3; i++) {
+        f(1, found_ref[i]);
+        if (current->found_ref[i])
+            break;
+    }
+    if (i >= 3)
+        CHECK(FUNC(frame_size)(ctx, rw, current));
+    CHECK(FUNC(render_size)(ctx, rw, current));
+
+    return 0;
+}
+
+static int FUNC(interpolation_filter)(CodedBitstreamContext *ctx, RWContext *rw,
+                                      VP9RawFrameHeader *current)
+{
+    int err;
+
+    f(1, is_filter_switchable);
+    if (!current->is_filter_switchable)
+        f(2, raw_interpolation_filter_type);
+
+    return 0;
+}
+
+static int FUNC(loop_filter_params)(CodedBitstreamContext *ctx, RWContext *rw,
+                                    VP9RawFrameHeader *current)
+{
+    int err, i;
+
+    f(6, loop_filter_level);
+    f(3, loop_filter_sharpness);
+
+    f(1, loop_filter_delta_enabled);
+    if (current->loop_filter_delta_enabled) {
+        f(1, loop_filter_delta_update);
+        if (current->loop_filter_delta_update) {
+            for (i = 0; i < 4; i++) {
+                f(1, update_ref_delta[i]);
+                if (current->update_ref_delta[i])
+                    s(6, loop_filter_ref_deltas[i]);
+            }
+            for (i = 0; i < 2; i++) {
+                f(1, update_mode_delta[i]);
+                if (current->update_mode_delta[i])
+                    s(6, loop_filter_mode_deltas[i]);
+            }
+        }
+    }
+
+    return 0;
+}
+
+static int FUNC(quantization_params)(CodedBitstreamContext *ctx, RWContext *rw,
+                                     VP9RawFrameHeader *current)
+{
+    int err;
+
+    f(8, base_q_idx);
+
+    delta_q(delta_q_y_dc);
+    delta_q(delta_q_uv_dc);
+    delta_q(delta_q_uv_ac);
+
+    return 0;
+}
+
+static int FUNC(segmentation_params)(CodedBitstreamContext *ctx, RWContext *rw,
+                                     VP9RawFrameHeader *current)
+{
+    static const int segmentation_feature_bits[VP9_SEG_LVL_MAX]   = { 8, 6, 2, 0 };
+    static const int segmentation_feature_signed[VP9_SEG_LVL_MAX] = { 1, 1, 0, 0 };
+
+    int err, i, j;
+
+    f(1, segmentation_enabled);
+
+    if (current->segmentation_enabled) {
+        f(1, segmentation_update_map);
+        if (current->segmentation_update_map) {
+            for (i = 0; i < 7; i++)
+                prob(segmentation_tree_probs[i]);
+            f(1, segmentation_temporal_update);
+            for (i = 0; i < 3; i++) {
+                if (current->segmentation_temporal_update)
+                    prob(segmentation_pred_prob[i]);
+                else
+                    infer(segmentation_pred_prob[i], 255);
+            }
+        }
+
+        f(1, segmentation_update_data);
+        if (current->segmentation_update_data) {
+            f(1, segmentation_abs_or_delta_update);
+            for (i = 0; i < VP9_MAX_SEGMENTS; i++) {
+                for (j = 0; j < VP9_SEG_LVL_MAX; j++) {
+                    f(1, feature_enabled[i][j]);
+                    if (current->feature_enabled[i][j] &&
+                        segmentation_feature_bits[j]) {
+                        f(segmentation_feature_bits[j], feature_value[i][j]);
+                        if (segmentation_feature_signed[j])
+                            f(1, feature_sign[i][j]);
+                        else
+                            infer(feature_sign[i][j], 0);
+                    } else {
+                        infer(feature_value[i][j], 0);
+                        infer(feature_sign[i][j],  0);
+                    }
+                }
+            }
+        }
+    }
+
+    return 0;
+}
+
+static int FUNC(tile_info)(CodedBitstreamContext *ctx, RWContext *rw,
+                           VP9RawFrameHeader *current)
+{
+    CodedBitstreamVP9Context *vp9 = ctx->priv_data;
+    int min_log2_tile_cols, max_log2_tile_cols;
+    int err;
+
+    min_log2_tile_cols = 0;
+    while ((VP9_MAX_TILE_WIDTH_B64 << min_log2_tile_cols) < vp9->sb64_cols)
+        ++min_log2_tile_cols;
+    max_log2_tile_cols = 0;
+    while ((vp9->sb64_cols >> (max_log2_tile_cols + 1)) >= VP9_MIN_TILE_WIDTH_B64)
+        ++max_log2_tile_cols;
+
+    increment(tile_cols_log2, min_log2_tile_cols, max_log2_tile_cols);
+
+    increment(tile_rows_log2, 0, 2);
+
+    return 0;
+}
+
+static int FUNC(uncompressed_header)(CodedBitstreamContext *ctx, RWContext *rw,
+                                     VP9RawFrameHeader *current)
+{
+    int profile, i;
+    int err;
+
+    f(2, frame_marker);
+
+    f(1, profile_low_bit);
+    f(1, profile_high_bit);
+    profile = (current->profile_high_bit << 1) + current->profile_low_bit;
+    if (profile == 3)
+        f(1, profile_reserved_zero);
+
+    f(1, show_existing_frame);
+    if (current->show_existing_frame) {
+        f(3, frame_to_show_map_idx);
+        infer(header_size_in_bytes, 0);
+        infer(refresh_frame_flags,  0x00);
+        infer(loop_filter_level,    0);
+        return 0;
+    }
+
+    f(1, frame_type);
+    f(1, show_frame);
+    f(1, error_resilient_mode);
+
+    if (current->frame_type == 0) {
+        CHECK(FUNC(frame_sync_code)(ctx, rw, current));
+        CHECK(FUNC(color_config)(ctx, rw, current, profile));
+        CHECK(FUNC(frame_size)(ctx, rw, current));
+        CHECK(FUNC(render_size)(ctx, rw, current));
+
+        infer(refresh_frame_flags, 0xff);
+
+    } else {
+         if (current->show_frame == 0)
+             f(1, intra_only);
+         else
+             infer(intra_only, 0);
+
+         if (current->error_resilient_mode == 0)
+             f(2, reset_frame_context);
+         else
+             infer(reset_frame_context, 0);
+
+         if (current->intra_only == 1) {
+             CHECK(FUNC(frame_sync_code)(ctx, rw, current));
+
+             if (profile > 0) {
+                 CHECK(FUNC(color_config)(ctx, rw, current, profile));
+             } else {
+                 infer(color_space,   1);
+                 infer(subsampling_x, 1);
+                 infer(subsampling_y, 1);
+             }
+
+             f(8, refresh_frame_flags);
+
+             CHECK(FUNC(frame_size)(ctx, rw, current));
+             CHECK(FUNC(render_size)(ctx, rw, current));
+         } else {
+             f(8, refresh_frame_flags);
+
+             for (i = 0; i < 3; i++) {
+                 f(3, ref_frame_idx[i]);
+                 f(1, ref_frame_sign_bias[i]);
+             }
+
+             CHECK(FUNC(frame_size_with_refs)(ctx, rw, current));
+             f(1, allow_high_precision_mv);
+             CHECK(FUNC(interpolation_filter)(ctx, rw, current));
+         }
+    }
+
+    if (current->error_resilient_mode == 0) {
+        f(1, refresh_frame_context);
+        f(1, frame_parallel_decoding_mode);
+    } else {
+        infer(refresh_frame_context,        0);
+        infer(frame_parallel_decoding_mode, 1);
+    }
+
+    f(2, frame_context_idx);
+
+    CHECK(FUNC(loop_filter_params)(ctx, rw, current));
+    CHECK(FUNC(quantization_params)(ctx, rw, current));
+    CHECK(FUNC(segmentation_params)(ctx, rw, current));
+    CHECK(FUNC(tile_info)(ctx, rw, current));
+
+    f(16, header_size_in_bytes);
+
+    return 0;
+}
+
+static int FUNC(trailing_bits)(CodedBitstreamContext *ctx, RWContext *rw)
+{
+    int err;
+    av_unused int zero = 0;
+    while (byte_alignment(rw) != 0)
+        xf(1, zero_bit, zero);
+
+    return 0;
+}
+
+static int FUNC(frame)(CodedBitstreamContext *ctx, RWContext *rw,
+                       VP9RawFrame *current)
+{
+    int err;
+
+    HEADER("Frame");
+
+    CHECK(FUNC(uncompressed_header)(ctx, rw, &current->header));
+
+    CHECK(FUNC(trailing_bits)(ctx, rw));
+
+    return 0;
+}
+
+static int FUNC(superframe_index)(CodedBitstreamContext *ctx, RWContext *rw,
+                                  VP9RawSuperframeIndex *current)
+{
+    int err, i;
+
+    HEADER("Superframe Index");
+
+    f(3, superframe_marker);
+    f(2, bytes_per_framesize_minus_1);
+    f(3, frames_in_superframe_minus_1);
+
+    for (i = 0; i <= current->frames_in_superframe_minus_1; i++) {
+        // Surprise little-endian!
+        fle(8 * (current->bytes_per_framesize_minus_1 + 1),
+            frame_sizes[i]);
+    }
+
+    f(3, superframe_marker);
+    f(2, bytes_per_framesize_minus_1);
+    f(3, frames_in_superframe_minus_1);
+
+    return 0;
+}
-- 
2.16.1



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