[FFmpeg-devel] [PATCH] avcodec/pngdec: init zlib on decoder init.

[Nicolas George]

Le decadi 30 brumaire, an CCXXIII, Benoit Fouet a écrit :
> ---
>  libavcodec/pngdec.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
> index 57b73c1..8467443 100644
> --- a/libavcodec/pngdec.c
> +++ b/libavcodec/pngdec.c
> @@ -924,16 +924,6 @@ static int decode_frame_png(AVCodecContext *avctx,
>  
>      s->y = s->state = 0;
>  

> -    /* init the zlib */
> -    s->zstream.zalloc = ff_png_zalloc;
> -    s->zstream.zfree  = ff_png_zfree;
> -    s->zstream.opaque = NULL;
> -    ret = inflateInit(&s->zstream);
> -    if (ret != Z_OK) {
> -        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
> -        return AVERROR_EXTERNAL;
> -    }

> I expect the new patch should address your issue.

AFAICS, the buffer is still inited once and for all and not reset between
frames. Or did I miss something?

> -
>      if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
>          goto the_end;
>  
> @@ -944,7 +934,6 @@ static int decode_frame_png(AVCodecContext *avctx,
>  
>      ret = bytestream2_tell(&s->gb);
>  the_end:
> -    inflateEnd(&s->zstream);
>      s->crow_buf = NULL;
>      return ret;
>  }
> @@ -967,6 +956,7 @@ static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
>  static av_cold int png_dec_init(AVCodecContext *avctx)
>  {
>      PNGDecContext *s = avctx->priv_data;
> +    int ret;
>  
>      s->avctx = avctx;
>      s->last_picture.f = av_frame_alloc();
> @@ -979,6 +969,16 @@ static av_cold int png_dec_init(AVCodecContext *avctx)
>          ff_pngdsp_init(&s->dsp);
>      }
>  
> +    /* init the zlib */
> +    s->zstream.zalloc = ff_png_zalloc;
> +    s->zstream.zfree  = ff_png_zfree;
> +    s->zstream.opaque = NULL;
> +    ret = inflateInit(&s->zstream);
> +    if (ret != Z_OK) {
> +        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
> +        return AVERROR_EXTERNAL;
> +    }
> +
>      return 0;
>  }
>  
> @@ -996,6 +996,7 @@ static av_cold int png_dec_end(AVCodecContext *avctx)
>      s->last_row_size = 0;
>      av_freep(&s->tmp_row);
>      s->tmp_row_size = 0;
> +    inflateEnd(&s->zstream);
>  
>      return 0;
>  }

Regards,

-- 
  Nicolas George
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