PR #22352 opened by James Almer (jamrial)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22352
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22352.patch

Including a parser to assemble entire Access Units.


>From ea587066055828b5b7711228a2939614415df316 Mon Sep 17 00:00:00 2001
From: James Almer <[email protected]>
Date: Mon, 2 Mar 2026 18:10:39 -0300
Subject: [PATCH 1/2] avcodec: add an LCEVC parser

Signed-off-by: James Almer <[email protected]>
---
 libavcodec/lcevc_parser.c | 88 +++++++++++++++++++++++++++++++++++++++
 libavcodec/parsers.c      |  1 +
 2 files changed, 89 insertions(+)
 create mode 100644 libavcodec/lcevc_parser.c

diff --git a/libavcodec/lcevc_parser.c b/libavcodec/lcevc_parser.c
new file mode 100644
index 0000000000..c737fada59
--- /dev/null
+++ b/libavcodec/lcevc_parser.c
@@ -0,0 +1,88 @@
+/*
+ * 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 <stdint.h>
+
+#include "libavutil/mem.h"
+
+#include "avcodec.h"
+#include "lcevc.h"
+#include "parser.h"
+#include "parser_internal.h"
+
+#define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
+
+static int lcevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
+                                int buf_size)
+{
+    ParseContext *pc = s->priv_data;
+
+    for (int i = 0; i < buf_size; i++) {
+        int nut;
+
+        pc->state = (pc->state << 8) | buf[i];
+
+        if (((pc->state >> 8) & 0xFFFFFF) != START_CODE)
+            continue;
+
+        nut = (pc->state >> 1) & 0x1F;
+
+        // Beginning of access unit
+        if (nut == LCEVC_IDR_NUT || nut == LCEVC_NON_IDR_NUT) {
+            if (!pc->frame_start_found)
+                pc->frame_start_found = 1;
+            else {
+                pc->frame_start_found = 0;
+                return i - 3;
+            }
+        }
+    }
+
+    return END_NOT_FOUND;
+}
+
+static int lcevc_parse(AVCodecParserContext *s,
+                      AVCodecContext *avctx,
+                      const uint8_t **poutbuf, int *poutbuf_size,
+                      const uint8_t *buf, int buf_size)
+{
+    ParseContext *pc = s->priv_data;
+    int next;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
+        next = buf_size;
+    } else {
+        next = lcevc_find_frame_end(s, buf, buf_size);
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+            *poutbuf      = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+const FFCodecParser ff_lcevc_parser = {
+    PARSER_CODEC_LIST(AV_CODEC_ID_LCEVC),
+    .priv_data_size = sizeof(ParseContext),
+    .parse          = lcevc_parse,
+    .close          = ff_parse_close,
+};
diff --git a/libavcodec/parsers.c b/libavcodec/parsers.c
index 4561f6eb3d..162b96cb69 100644
--- a/libavcodec/parsers.c
+++ b/libavcodec/parsers.c
@@ -78,6 +78,7 @@ extern const FFCodecParser ff_ipu_parser;
 extern const FFCodecParser ff_jpeg2000_parser;
 extern const FFCodecParser ff_jpegxl_parser;
 extern const FFCodecParser ff_jpegxs_parser;
+extern const FFCodecParser ff_lcevc_parser;
 extern const FFCodecParser ff_misc4_parser;
 extern const FFCodecParser ff_mjpeg_parser;
 extern const FFCodecParser ff_mlp_parser;
-- 
2.52.0


>From 5ee0872519c416a8f59ccebc8eb91f4f0ee88303 Mon Sep 17 00:00:00 2001
From: James Almer <[email protected]>
Date: Mon, 2 Mar 2026 19:49:57 -0300
Subject: [PATCH 2/2] avformat/mpegts: add basic support for LCEVC streams

As defined in ITU-T H.222.0 v9.
LCEVC streams use the "Byte stream format" defined in Annex B of
ISO/IEC 23094-2:2021.

Signed-off-by: James Almer <[email protected]>
---
 libavformat/mpegts.c | 1 +
 libavformat/mpegts.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index a9094ab55b..40153c7c9a 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -816,6 +816,7 @@ static const StreamType ISO_types[] = {
     { STREAM_TYPE_VIDEO_JPEG2000, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_JPEG2000   },
     { STREAM_TYPE_VIDEO_HEVC,     AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_HEVC       },
     { STREAM_TYPE_VIDEO_JPEGXS,   AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_JPEGXS     },
+    { STREAM_TYPE_VIDEO_LCEVC,    AVMEDIA_TYPE_DATA,  AV_CODEC_ID_LCEVC      },
     { STREAM_TYPE_VIDEO_VVC,      AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_VVC        },
     { STREAM_TYPE_VIDEO_CAVS,     AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_CAVS       },
     { STREAM_TYPE_VIDEO_DIRAC,    AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_DIRAC      },
diff --git a/libavformat/mpegts.h b/libavformat/mpegts.h
index 223962d18e..baaf9365eb 100644
--- a/libavformat/mpegts.h
+++ b/libavformat/mpegts.h
@@ -146,6 +146,7 @@
 #define STREAM_TYPE_VIDEO_HEVC      0x24
 #define STREAM_TYPE_VIDEO_JPEGXS    0x32
 #define STREAM_TYPE_VIDEO_VVC       0x33
+#define STREAM_TYPE_VIDEO_LCEVC     0x36
 #define STREAM_TYPE_VIDEO_CAVS      0x42
 #define STREAM_TYPE_VIDEO_AVS2      0xd2
 #define STREAM_TYPE_VIDEO_AVS3      0xd4
-- 
2.52.0

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