[FFmpeg-devel] [PATCH 1/3] avcodec/cbs_av1: add support for Padding OBUs

[James Almer]

Based on itut_t35 Matadata OBU parsing code.

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/cbs_av1.c                 | 20 +++++++++++++++++
 libavcodec/cbs_av1.h                 |  7 ++++++
 libavcodec/cbs_av1_syntax_template.c | 32 ++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+)

diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
index 02f168b58d..22330eabf3 100644
--- a/libavcodec/cbs_av1.c
+++ b/libavcodec/cbs_av1.c
@@ -857,6 +857,11 @@ static void cbs_av1_free_tile_data(AV1RawTileData *td)
     av_buffer_unref(&td->data_ref);
 }
 
+static void cbs_av1_free_padding(AV1RawPadding *pd)
+{
+    av_buffer_unref(&pd->payload_ref);
+}
+
 static void cbs_av1_free_metadata(AV1RawMetadata *md)
 {
     switch (md->metadata_type) {
@@ -883,6 +888,9 @@ static void cbs_av1_free_obu(void *unit, uint8_t *content)
     case AV1_OBU_METADATA:
         cbs_av1_free_metadata(&obu->obu.metadata);
         break;
+    case AV1_OBU_PADDING:
+        cbs_av1_free_padding(&obu->obu.padding);
+        break;
     }
 
     av_freep(&obu);
@@ -1057,6 +1065,12 @@ static int cbs_av1_read_unit(CodedBitstreamContext *ctx,
         }
         break;
     case AV1_OBU_PADDING:
+        {
+            err = cbs_av1_read_padding(ctx, &gbc, &obu->obu.padding);
+            if (err < 0)
+                return err;
+        }
+        break;
     default:
         return AVERROR(ENOSYS);
     }
@@ -1182,6 +1196,12 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
         }
         break;
     case AV1_OBU_PADDING:
+        {
+            err = cbs_av1_write_padding(ctx, pbc, &obu->obu.padding);
+            if (err < 0)
+                return err;
+        }
+        break;
     default:
         return AVERROR(ENOSYS);
     }
diff --git a/libavcodec/cbs_av1.h b/libavcodec/cbs_av1.h
index 71ceff9427..e799964b72 100644
--- a/libavcodec/cbs_av1.h
+++ b/libavcodec/cbs_av1.h
@@ -364,6 +364,12 @@ typedef struct AV1RawMetadata {
     } metadata;
 } AV1RawMetadata;
 
+typedef struct AV1RawPadding {
+    uint8_t     *payload;
+    size_t       payload_size;
+    AVBufferRef *payload_ref;
+} AV1RawPadding;
+
 
 typedef struct AV1RawOBU {
     AV1RawOBUHeader header;
@@ -377,6 +383,7 @@ typedef struct AV1RawOBU {
         AV1RawTileGroup      tile_group;
         AV1RawTileList       tile_list;
         AV1RawMetadata       metadata;
+        AV1RawPadding        padding;
     } obu;
 } AV1RawOBU;
 
diff --git a/libavcodec/cbs_av1_syntax_template.c b/libavcodec/cbs_av1_syntax_template.c
index 76eb90b279..a6cafdd99f 100644
--- a/libavcodec/cbs_av1_syntax_template.c
+++ b/libavcodec/cbs_av1_syntax_template.c
@@ -1763,3 +1763,35 @@ static int FUNC(metadata_obu)(CodedBitstreamContext *ctx, RWContext *rw,
 
     return 0;
 }
+
+static int FUNC(padding)(CodedBitstreamContext *ctx, RWContext *rw,
+                         AV1RawPadding *current)
+{
+    int i, err;
+
+    HEADER("Padding");
+
+#ifdef READ
+    // The payload runs up to the start of the trailing bits, but there might
+    // be arbitrarily many trailing zeroes so we need to read through twice.
+    {
+        GetBitContext tmp = *rw;
+        current->payload_size = 0;
+        for (i = 0; get_bits_left(rw) >= 8; i++) {
+            if (get_bits(rw, 8))
+                current->payload_size = i;
+        }
+        *rw = tmp;
+
+        current->payload_ref = av_buffer_alloc(current->payload_size);
+        if (!current->payload_ref)
+            return AVERROR(ENOMEM);
+        current->payload = current->payload_ref->data;
+    }
+#endif
+
+    for (i = 0; i < current->payload_size; i++)
+        xf(8, obu_padding_byte[i], current->payload[i], 0x00, 0xff, 1, i);
+
+    return 0;
+}
-- 
2.21.0