[FFmpeg-devel] [PATCH] avcodec/vvc/refs: export in-band LCEVC side data in frames (PR #21154)

[FFmpeg-devel] [PATCH] avcodec/vvc/refs: export in-band LCEVC side data in frames (PR #21154)

[James Almer via ffmpeg-devel]

PR #21154 opened by James Almer (jamrial)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21154
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21154.patch


>From e86bd0784a28d0baf7f3fb097dcd3f9e2ea8b350 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Mon, 8 Dec 2025 22:35:33 -0300
Subject: [PATCH 1/3] avcodec/cbs_sei: store a pointer to the start of
 Registered and Unregistered SEI messages

Required for the following commit, where a parsing function expects the buffer
to include the country code bytes.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/cbs_sei.c                 |  4 ++--
 libavcodec/cbs_sei.h                 |  6 ++++--
 libavcodec/cbs_sei_syntax_template.c | 15 ++++++++++++++-
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/libavcodec/cbs_sei.c b/libavcodec/cbs_sei.c
index acc3578aa9..d57901f15d 100644
--- a/libavcodec/cbs_sei.c
+++ b/libavcodec/cbs_sei.c
@@ -28,13 +28,13 @@
 static void cbs_free_user_data_registered(AVRefStructOpaque unused, void *obj)
 {
     SEIRawUserDataRegistered *udr = obj;
-    av_refstruct_unref(&udr->data);
+    av_refstruct_unref(&udr->data_ref);
 }
 
 static void cbs_free_user_data_unregistered(AVRefStructOpaque unused, void *obj)
 {
     SEIRawUserDataUnregistered *udu = obj;
-    av_refstruct_unref(&udu->data);
+    av_refstruct_unref(&udu->data_ref);
 }
 
 int ff_cbs_sei_alloc_message_payload(SEIRawMessage *message,
diff --git a/libavcodec/cbs_sei.h b/libavcodec/cbs_sei.h
index 81867b79a7..decc4e19e1 100644
--- a/libavcodec/cbs_sei.h
+++ b/libavcodec/cbs_sei.h
@@ -33,13 +33,15 @@ typedef struct SEIRawFillerPayload {
 typedef struct SEIRawUserDataRegistered {
     uint8_t      itu_t_t35_country_code;
     uint8_t      itu_t_t35_country_code_extension_byte;
-    uint8_t     *data; ///< RefStruct reference
+    uint8_t     *data;
+    uint8_t     *data_ref; ///< RefStruct reference
     size_t       data_length;
 } SEIRawUserDataRegistered;
 
 typedef struct SEIRawUserDataUnregistered {
     uint8_t      uuid_iso_iec_11578[16];
-    uint8_t     *data; ///< RefStruct reference
+    uint8_t     *data;
+    uint8_t     *data_ref; ///< RefStruct reference
     size_t       data_length;
 } SEIRawUserDataUnregistered;
 
diff --git a/libavcodec/cbs_sei_syntax_template.c b/libavcodec/cbs_sei_syntax_template.c
index e6863a0fd7..f70eb24d80 100644
--- a/libavcodec/cbs_sei_syntax_template.c
+++ b/libavcodec/cbs_sei_syntax_template.c
@@ -57,9 +57,16 @@ SEI_FUNC(user_data_registered, (CodedBitstreamContext *ctx, RWContext *rw,
         return AVERROR_INVALIDDATA;
     }
     current->data_length = state->payload_size - i;
-#endif
 
+    allocate(current->data_ref, state->payload_size);
+    current->data = current->data_ref;
+
+    *current->data++ = current->itu_t_t35_country_code;
+    if (current->itu_t_t35_country_code == 0xff)
+        *current->data++ = current->itu_t_t35_country_code_extension_byte;
+#else
     allocate(current->data, current->data_length);
+#endif
     for (j = 0; j < current->data_length; j++)
         xu(8, itu_t_t35_payload_byte[], current->data[j], 0x00, 0xff, 1, i + j);
 
@@ -86,7 +93,13 @@ SEI_FUNC(user_data_unregistered, (CodedBitstreamContext *ctx, RWContext *rw,
     for (i = 0; i < 16; i++)
         us(8, uuid_iso_iec_11578[i], 0x00, 0xff, 1, i);
 
+#ifdef READ
+    allocate(current->data_ref, state->payload_size);
+    memcpy(current->data_ref, current->uuid_iso_iec_11578, sizeof(current->uuid_iso_iec_11578));
+    current->data = current->data_ref + 16;
+#else
     allocate(current->data, current->data_length);
+#endif
 
     for (i = 0; i < current->data_length; i++)
         xu(8, user_data_payload_byte[i], current->data[i], 0x00, 0xff, 1, i);
-- 
2.49.1


>From 3456c8439a89699123ea2b1a5c4f92e00c688614 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Mon, 8 Dec 2025 22:36:18 -0300
Subject: [PATCH 2/3] avcodec/vvc/sei: parse Registered and Unregistered SEI
 messages

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/vvc/sei.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/libavcodec/vvc/sei.c b/libavcodec/vvc/sei.c
index cd202edb2a..241943f3c1 100644
--- a/libavcodec/vvc/sei.c
+++ b/libavcodec/vvc/sei.c
@@ -22,6 +22,7 @@
 
 #include "sei.h"
 #include "dec.h"
+#include "libavcodec/bytestream.h"
 #include "libavutil/refstruct.h"
 
 static int decode_film_grain_characteristics(H2645SEIFilmGrainCharacteristics *h, const SEIRawFilmGrainCharacteristics *s, const VVCFrameContext *fc)
@@ -176,6 +177,27 @@ static int decode_mastering_display_colour_volume(H2645SEIMasteringDisplay *h, c
     return 0;
 }
 
+static int decode_user_data_registered_itu_t_t35(H2645SEI *sei, const SEIRawUserDataRegistered *s,
+                                                 const VVCFrameContext *fc)
+{
+    GetByteContext gbc;
+    int offset = (s->itu_t_t35_country_code == 0xff) + 1;
+
+    bytestream2_init(&gbc, s->data_ref, s->data_length + offset);
+    return ff_h2645_sei_message_decode(sei, SEI_TYPE_USER_DATA_REGISTERED_ITU_T_T35,
+                                       AV_CODEC_ID_VVC, NULL, &gbc, fc->log_ctx);
+}
+
+static int decode_user_data_uregistered(H2645SEI *sei, const SEIRawUserDataUnregistered *s,
+                                        const VVCFrameContext *fc)
+{
+    GetByteContext gbc;
+
+    bytestream2_init(&gbc, s->data_ref, s->data_length + 16);
+    return ff_h2645_sei_message_decode(sei, SEI_TYPE_USER_DATA_UNREGISTERED,
+                                       AV_CODEC_ID_VVC, NULL, &gbc, fc->log_ctx);
+}
+
 int ff_vvc_sei_decode(VVCSEI *s, const H266RawSEI *sei, const struct VVCFrameContext *fc)
 {
     H2645SEI *c  = &s->common;
@@ -221,6 +243,14 @@ int ff_vvc_sei_decode(VVCSEI *s, const H266RawSEI *sei, const struct VVCFrameCon
             ret = decode_mastering_display_colour_volume(&s->common.mastering_display, payload);
             break;
 
+        case SEI_TYPE_USER_DATA_REGISTERED_ITU_T_T35:
+            ret = decode_user_data_registered_itu_t_t35(&s->common, payload, fc);
+            break;
+
+        case SEI_TYPE_USER_DATA_UNREGISTERED:
+            ret = decode_user_data_uregistered(&s->common, payload, fc);
+            break;
+
         default:
             av_log(fc->log_ctx, AV_LOG_DEBUG, "Skipped %s SEI %d\n",
                 sei->nal_unit_header.nal_unit_type == VVC_PREFIX_SEI_NUT ?
-- 
2.49.1


>From 7ac1a20f5319c19190dac6bf0115c9bb36d82261 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Tue, 9 Dec 2025 14:36:22 -0300
Subject: [PATCH 3/3] avcodec/vvc/refs: export in-band LCEVC side data in
 frames

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/vvc/dec.c  | 5 +++--
 libavcodec/vvc/refs.c | 9 +++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/libavcodec/vvc/dec.c b/libavcodec/vvc/dec.c
index 028f34b491..194e2fc7ef 100644
--- a/libavcodec/vvc/dec.c
+++ b/libavcodec/vvc/dec.c
@@ -807,11 +807,11 @@ static int frame_start(VVCContext *s, VVCFrameContext *fc, SliceContext *sc)
     if (!s->temporal_id && !ph->r->ph_non_ref_pic_flag && !(IS_RASL(s) || IS_RADL(s)))
         s->poc_tid0 = ph->poc;
 
+    decode_prefix_sei(fc, s);
+
     if ((ret = ff_vvc_set_new_ref(s, fc, &fc->frame)) < 0)
         goto fail;
 
-    decode_prefix_sei(fc, s);
-
     ret = set_side_data(s, fc);
     if (ret < 0)
         goto fail;
@@ -1225,6 +1225,7 @@ static av_cold void vvc_decode_flush(AVCodecContext *avctx)
 
     if (s->fcs) {
         VVCFrameContext *last = get_frame_context(s, s->fcs, s->nb_frames - 1);
+        ff_vvc_sei_reset(&last->sei);
         ff_vvc_flush_dpb(last);
     }
 
diff --git a/libavcodec/vvc/refs.c b/libavcodec/vvc/refs.c
index f134a100b4..c1f027aed5 100644
--- a/libavcodec/vvc/refs.c
+++ b/libavcodec/vvc/refs.c
@@ -133,6 +133,15 @@ static VVCFrame *alloc_frame(VVCContext *s, VVCFrameContext *fc)
         frame->sps = av_refstruct_ref_c(fc->ps.sps);
         frame->pps = av_refstruct_ref_c(fc->ps.pps);
 
+        // Add LCEVC SEI metadata here, as it's needed in get_buffer()
+        if (fc->sei.common.lcevc.info) {
+            HEVCSEILCEVC *lcevc = &fc->sei.common.lcevc;
+            ret = ff_frame_new_side_data_from_buf(s->avctx, frame->frame,
+                                                  AV_FRAME_DATA_LCEVC, &lcevc->info);
+            if (ret < 0)
+                goto fail;
+        }
+
         ret = ff_thread_get_buffer(s->avctx, frame->frame, AV_GET_BUFFER_FLAG_REF);
         if (ret < 0)
             return NULL;
-- 
2.49.1

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