Re: [FFmpeg-devel] [PATCH 1/8] libavcodec/jpeg2000_parser: Speed up long skips

[Anton Khirnov <anton@khirnov.net>]

Quoting Tomas Härdin (2022-05-31 11:58:39)
> 
> 
> From fedd7f9ae2c691a25c37be935d7547be61d46017 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Tomas=20H=C3=A4rdin?= <git@haerdin.se>
> Date: Fri, 20 May 2022 11:38:25 +0200
> Subject: [PATCH 1/8] libavcodec/jpeg2000_parser: Speed up long skips
> 
> ---
>  libavcodec/jpeg2000_parser.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/libavcodec/jpeg2000_parser.c b/libavcodec/jpeg2000_parser.c
> index 2975e71482..9fac958dfa 100644
> --- a/libavcodec/jpeg2000_parser.c
> +++ b/libavcodec/jpeg2000_parser.c
> @@ -95,6 +95,17 @@ static int find_frame_end(JPEG2000ParserContext *m, const uint8_t *buf, int buf_
>          state64 = state64 << 8 | buf[i];
>          m->bytes_read++;
>          if (m->skip_bytes) {
> +            // handle long skips
> +            if (m->skip_bytes > 8) {
> +                // need -9 else buf_size - i == 8 ==> i == buf_size after this,
> +                // and thus i == buf_size + 1 after the loop
> +                int64_t skip = FFMIN(m->skip_bytes - 8, buf_size - i - 9);
> +                if (skip > 0) {
> +                    m->skip_bytes -= skip;
> +                    i += skip;
> +                    m->bytes_read += skip;

Shouldn't you also update state(64)?

-- 
Anton Khirnov
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