[FFmpeg-devel] [PATCH 3/7] avformat/av1: Avoid allocation for small headers

[James Almer]

On 11/27/2019 9:22 AM, Andreas Rheinhardt wrote:
> By using avio_get_dyn_buf() + ffio_free_dyn_buf() instead of
> avio_close_dyn_buf() + av_free() one can avoid an allocation + copy for
> small headers. Furthermore, it simplifies freeing.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
>  libavformat/av1.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/libavformat/av1.c b/libavformat/av1.c
> index 03669dfd2a..132f4e987b 100644
> --- a/libavformat/av1.c
> +++ b/libavformat/av1.c
> @@ -326,7 +326,7 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
>      AV1SequenceParameters seq_params;
>      PutBitContext pbc;
>      uint8_t header[4];
> -    uint8_t *seq = NULL, *meta = NULL;
> +    uint8_t *seq, *meta;
>      int64_t obu_size;
>      int start_pos, type, temporal_id, spatial_id;
>      int ret, nb_seq = 0, seq_size, meta_size;
> @@ -376,7 +376,7 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
>          buf  += len;
>      }
>  
> -    seq_size  = avio_close_dyn_buf(seq_pb, &seq);
> +    seq_size  = avio_get_dyn_buf(seq_pb, &seq);
>      if (!seq_size) {
>          ret = AVERROR_INVALIDDATA;
>          goto fail;
> @@ -401,17 +401,13 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
>      avio_write(pb, header, sizeof(header));
>      avio_write(pb, seq, seq_size);
>  
> -    meta_size = avio_close_dyn_buf(meta_pb, &meta);
> +    meta_size = avio_get_dyn_buf(meta_pb, &meta);
>      if (meta_size)
>          avio_write(pb, meta, meta_size);
>  
>  fail:
> -    if (!seq)
> -        avio_close_dyn_buf(seq_pb, &seq);
> -    if (!meta)
> -        avio_close_dyn_buf(meta_pb, &meta);
> -    av_free(seq);
> -    av_free(meta);
> +    ffio_free_dyn_buf(&seq_pb);
> +    ffio_free_dyn_buf(&meta_pb);
>  
>      return ret;
>  }

Ah, I had this written and queued for when i pushed my avcC patch with
your suggested changes, but will apply yours instead since you actually
sent it first.