[FFmpeg-devel] [PATCH] avcodec/h2645_parse: add a flag to store skipped byte positions

[James Almer]

This is only used by two out of several modules, so it's a waste of resources
for the rest.

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/cbs_h2645.c    |  6 ++++--
 libavcodec/h2645_parse.c  | 10 ++++++----
 libavcodec/h2645_parse.h  |  1 +
 libavcodec/hevc/hevcdec.c |  2 +-
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 4abd9e0c2e..75c1d1c4cf 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -725,7 +725,8 @@ static int cbs_h2645_split_fragment(CodedBitstreamContext *ctx,
             err = ff_h2645_packet_split(&priv->read_packet,
                                         frag->data + start, end - start,
                                         ctx->log_ctx, 2, AV_CODEC_ID_VVC,
-                                        H2645_FLAG_IS_NALFF | H2645_FLAG_SMALL_PADDING | H2645_FLAG_USE_REF);
+                                        H2645_FLAG_IS_NALFF | H2645_FLAG_SMALL_PADDING |
+                                        H2645_FLAG_USE_REF | H2645_FLAG_SKIPPED_BYTES);
             if (err < 0) {
                 av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to split "
                        "VVCC array %d (%d NAL units of type %d).\n",
@@ -737,7 +738,8 @@ static int cbs_h2645_split_fragment(CodedBitstreamContext *ctx,
                 return err;
         }
     } else {
-        int flags = (H2645_FLAG_IS_NALFF * !!priv->mp4) | H2645_FLAG_SMALL_PADDING | H2645_FLAG_USE_REF;
+        int flags = (H2645_FLAG_IS_NALFF * !!priv->mp4) | H2645_FLAG_SMALL_PADDING | H2645_FLAG_USE_REF |
+                    (H2645_FLAG_SKIPPED_BYTES * (codec_id == AV_CODEC_ID_VVC));
         // Annex B, or later MP4 with already-known parameters.
 
         err = ff_h2645_packet_split(&priv->read_packet,
diff --git a/libavcodec/h2645_parse.c b/libavcodec/h2645_parse.c
index 7b48fcae17..f8eb301680 100644
--- a/libavcodec/h2645_parse.c
+++ b/libavcodec/h2645_parse.c
@@ -540,10 +540,12 @@ int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
             memset(pkt->nals + pkt->nals_allocated, 0, sizeof(*pkt->nals));
 
             nal = &pkt->nals[pkt->nb_nals];
-            nal->skipped_bytes_pos_size = FFMIN(1024, extract_length/3+1); // initial buffer size
-            nal->skipped_bytes_pos = av_malloc_array(nal->skipped_bytes_pos_size, sizeof(*nal->skipped_bytes_pos));
-            if (!nal->skipped_bytes_pos)
-                return AVERROR(ENOMEM);
+            if (flags & H2645_FLAG_SKIPPED_BYTES) {
+                nal->skipped_bytes_pos_size = FFMIN(1024, extract_length/3+1); // initial buffer size
+                nal->skipped_bytes_pos = av_malloc_array(nal->skipped_bytes_pos_size, sizeof(*nal->skipped_bytes_pos));
+                if (!nal->skipped_bytes_pos)
+                    return AVERROR(ENOMEM);
+            }
 
             pkt->nals_allocated = new_size;
         }
diff --git a/libavcodec/h2645_parse.h b/libavcodec/h2645_parse.h
index e27ccf7523..975000aeb7 100644
--- a/libavcodec/h2645_parse.h
+++ b/libavcodec/h2645_parse.h
@@ -97,6 +97,7 @@ enum {
     H2645_FLAG_IS_NALFF =         (1 << 0),
     H2645_FLAG_SMALL_PADDING =    (1 << 1),
     H2645_FLAG_USE_REF =          (1 << 2),
+    H2645_FLAG_SKIPPED_BYTES =    (1 << 3),
 };
 
 /**
diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c
index d915d74d22..8e2d52c51a 100644
--- a/libavcodec/hevc/hevcdec.c
+++ b/libavcodec/hevc/hevcdec.c
@@ -3321,7 +3321,7 @@ static int decode_nal_units(HEVCContext *s, const uint8_t *buf, int length)
 {
     int i, ret = 0;
     int eos_at_start = 1;
-    int flags = (H2645_FLAG_IS_NALFF * !!s->is_nalff) | H2645_FLAG_SMALL_PADDING;
+    int flags = (H2645_FLAG_IS_NALFF * !!s->is_nalff) | H2645_FLAG_SMALL_PADDING | H2645_FLAG_SKIPPED_BYTES;
 
     s->cur_frame = s->collocated_ref = NULL;
     s->last_eos = s->eos;
-- 
2.46.0