@@ -526,12 +526,13 @@ static int cbs_vp9_write_unit(CodedBitstreamContext *ctx,
{
CodedBitstreamVP9Context *priv = ctx->priv_data;
VP9RawFrame *frame = unit->content;
+ size_t header_size, data_size;
PutBitContext pbc;
int err;
if (!priv->write_buffer) {
- // Initial write buffer size is 1MB.
- priv->write_buffer_size = 1024 * 1024;
+ // Initial write buffer size is 1KB.
+ priv->write_buffer_size = 1024;
reallocate_and_try_again:
err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
@@ -556,27 +557,26 @@ static int cbs_vp9_write_unit(CodedBitstreamContext *ctx,
// Frame must be byte-aligned.
av_assert0(put_bits_count(&pbc) % 8 == 0);
- unit->data_size = put_bits_count(&pbc) / 8;
+ data_size = header_size = put_bits_count(&pbc) / 8;
unit->data_bit_padding = 0;
flush_put_bits(&pbc);
if (frame->data) {
- if (unit->data_size + frame->data_size >
- priv->write_buffer_size) {
- priv->write_buffer_size *= 2;
- goto reallocate_and_try_again;
- }
+ if (frame->data_size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE
+ - header_size)
+ return AVERROR(ENOMEM);
- memcpy(priv->write_buffer + unit->data_size,
- frame->data, frame->data_size);
- unit->data_size += frame->data_size;
+ data_size += frame->data_size;
}
- err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size);
+ err = ff_cbs_alloc_unit_data(ctx, unit, data_size);
if (err < 0)
return err;
- memcpy(unit->data, priv->write_buffer, unit->data_size);
+ memcpy(unit->data, priv->write_buffer, header_size);
+
+ if (frame->data)
+ memcpy(unit->data + header_size, frame->data, frame->data_size);
return 0;
}
Writing a unit (always a frame) in cbs_vp9 used an intermediate buffer to write the frame header followed by the frame data that was copied into said buffer. Afterwards, the final buffer for the frame was allocated and everything copied into this buffer. But it is trivial to compute the needed size of the final buffer after having written the header, so one can allocate the final buffer immediately and copy the frame data directly into it. Also, given that the intermediate buffer now only needs to keep the header, its size can be drastically reduced. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> --- I think that 1KB is still quite generous for the header; one could probably even come up with a drastically lower bound upon reading the spec (one could probably put the intermediate buffer on the stack and remove the reallocation stuff). Similar improvements can be done for the other cbs_*. vp9 is first because it seems to be the easiest. libavcodec/cbs_vp9.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-)