This commit makes use of the fact that the final unit buffer is now
allocated within write_unit to avoid a memcpy of tile data: It is now no
longer copied into an intermediate buffer before being written into the
final buffer, but directly written into the final buffer.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com>
---
libavcodec/cbs_av1.c | 89 +++++++++++++++++++++-----------------------
1 file changed, 42 insertions(+), 47 deletions(-)
diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
index 7ff5539fb8..54687f93d2 100644
--- a/libavcodec/cbs_av1.c
+++ b/libavcodec/cbs_av1.c
@@ -1060,28 +1060,9 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
CodedBitstreamAV1Context *priv = ctx->priv_data;
AV1RawOBU *obu = unit->content;
PutBitContext pbc_tmp;
- AV1RawTileData *td;
- size_t header_size;
- int err, start_pos, end_pos, data_pos;
-
- // OBUs in the normal bitstream format must contain a size field
- // in every OBU (in annex B it is optional, but we don't support
- // writing that).
- obu->header.obu_has_size_field = 1;
-
- err = cbs_av1_write_obu_header(ctx, pbc, &obu->header);
- if (err < 0)
- return err;
-
- if (obu->header.obu_has_size_field) {
- pbc_tmp = *pbc;
- // Add space for the size field to fill later.
- put_bits32(pbc, 0);
- put_bits32(pbc, 0);
- }
-
- td = NULL;
- start_pos = put_bits_count(pbc);
+ AV1RawTileData *td = NULL;
+ size_t header_size, obu_header_size, size, td_offset;
+ int err, end_pos;
priv->ref = (AV1ReferenceFrameState *)&priv->write_ref;
@@ -1168,8 +1149,9 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
}
end_pos = put_bits_count(pbc);
- header_size = (end_pos - start_pos + 7) / 8;
+ header_size = (end_pos + 7) / 8;
if (td) {
+ // The possible overflow here is checked below.
obu->obu_size = header_size + td->data_size;
} else if (header_size > 0) {
// Add trailing bits and recalculate.
@@ -1177,47 +1159,60 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
if (err < 0)
return err;
end_pos = put_bits_count(pbc);
- obu->obu_size = header_size = (end_pos - start_pos + 7) / 8;
+ obu->obu_size = header_size = (end_pos + 7) / 8;
} else {
// Empty OBU.
obu->obu_size = 0;
}
- end_pos = put_bits_count(pbc);
// Must now be byte-aligned.
av_assert0(end_pos % 8 == 0);
flush_put_bits(pbc);
- start_pos /= 8;
- end_pos /= 8;
- *pbc = pbc_tmp;
- err = cbs_av1_write_leb128(ctx, pbc, "obu_size", obu->obu_size);
+ obu_header_size = 1 + !!obu->header.obu_extension_flag
+ + (av_log2(obu->obu_size) + 7) / 7;
+
+ // The size of everything except the tile data.
+ size = td_offset = obu_header_size + header_size;
+
+ if (td) {
+ if (td->data_size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE
+ - size)
+ return AVERROR(ENOMEM);
+
+ // If we are here, header_size + td->data_size fits into an int,
+ // so a fortiori no overflow happened in the calculation of
+ // obu->obu_size which also fits in an int.
+ size += td->data_size;
+ }
+
+ err = ff_cbs_alloc_unit_data(ctx, unit, size);
if (err < 0)
return err;
- data_pos = put_bits_count(pbc) / 8;
- flush_put_bits(pbc);
- av_assert0(data_pos <= start_pos);
+ unit->data_bit_padding = 0;
- if (8 * obu->obu_size > put_bits_left(pbc))
- return AVERROR(ENOSPC);
+ init_put_bits(&pbc_tmp, unit->data, obu_header_size);
- if (obu->obu_size > 0) {
- memmove(pbc->buf + data_pos,
- pbc->buf + start_pos, header_size);
- skip_put_bytes(pbc, header_size);
+ // OBUs in the normal bitstream format must contain a size field
+ // in every OBU (in annex B it is optional, but we don't support
+ // writing that).
+ obu->header.obu_has_size_field = 1;
- if (td) {
- memcpy(pbc->buf + data_pos + header_size,
- td->data, td->data_size);
- skip_put_bytes(pbc, td->data_size);
- }
- }
+ err = cbs_av1_write_obu_header(ctx, &pbc_tmp, &obu->header);
+ if (err < 0)
+ return err;
- // OBU data must be byte-aligned.
- av_assert0(put_bits_count(pbc) % 8 == 0);
+ err = cbs_av1_write_leb128(ctx, &pbc_tmp, "obu_size", obu->obu_size);
+ av_assert0(err >= 0 && put_bits_left(&pbc_tmp) == 0);
+ flush_put_bits(&pbc_tmp);
- return ff_cbs_default_write_unit_data(ctx, unit, pbc);
+ memcpy(unit->data + obu_header_size, pbc->buf, header_size);
+
+ if (td)
+ memcpy(unit->data + td_offset, td->data, td->data_size);
+
+ return 0;
}
static int cbs_av1_assemble_fragment(CodedBitstreamContext *ctx,
--
2.20.1
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