[FFmpeg-devel] [PATCH]lavc/mpegvideo_enc: Do not write an extra RST tag after final jpeg slice

[Michael Niedermayer]

On Mon, Jan 20, 2020 at 12:54:21AM +0100, Carl Eugen Hoyos wrote:
> Hi!
> 
> Attached patch fixes ticket #8412.
> 
> Please comment, Carl Eugen

>  mpegvideo_enc.c |    7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 73d8636d0dba4f02cf1697b622c97945d738f06f  0001-lavc-mpegvideo_enc-Do-not-write-an-extra-RST-tag-aft.patch
> From 7f62ffa46f9264c1fc7854def8467816e0173883 Mon Sep 17 00:00:00 2001
> From: Carl Eugen Hoyos <ceffmpeg at gmail.com>
> Date: Mon, 20 Jan 2020 00:51:33 +0100
> Subject: [PATCH] lavc/mpegvideo_enc: Do not write an extra RST tag after final
>  jpeg slice.
> 
> Fixes ticket #8412.
> ---
>  libavcodec/mpegvideo_enc.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
> index 96f5b4a666..fc1c46fee7 100644
> --- a/libavcodec/mpegvideo_enc.c
> +++ b/libavcodec/mpegvideo_enc.c
> @@ -3566,8 +3566,9 @@ static void merge_context_after_me(MpegEncContext *dst, MpegEncContext *src){
>      MERGE(me.mb_var_sum_temp);
>  }
>  
> -static void merge_context_after_encode(MpegEncContext *dst, MpegEncContext *src){
> +static void merge_context_after_encode(MpegEncContext *dst, MpegEncContext *src, int last){
>      int i;
> +    int put_bits = put_bits_count(&src->pb) - (src->out_format == FMT_MJPEG && src->avctx->active_thread_type & FF_THREAD_SLICE && last ? 32 : 0);
>  
>      MERGE(dct_count[0]); //note, the other dct vars are not part of the context
>      MERGE(dct_count[1]);
> @@ -3594,7 +3595,7 @@ static void merge_context_after_encode(MpegEncContext *dst, MpegEncContext *src)
>  
>      av_assert1(put_bits_count(&src->pb) % 8 ==0);
>      av_assert1(put_bits_count(&dst->pb) % 8 ==0);
> -    avpriv_copy_bits(&dst->pb, src->pb.buf, put_bits_count(&src->pb));
> +    avpriv_copy_bits(&dst->pb, src->pb.buf, put_bits);
>      flush_put_bits(&dst->pb);
>  }
>  
> @@ -3919,7 +3920,7 @@ static int encode_picture(MpegEncContext *s, int picture_number)
>      for(i=1; i<context_count; i++){
>          if (s->pb.buf_end == s->thread_context[i]->pb.buf)
>              set_put_bits_buffer_size(&s->pb, FFMIN(s->thread_context[i]->pb.buf_end - s->pb.buf, INT_MAX/8-32));
> -        merge_context_after_encode(s, s->thread_context[i]);
> +        merge_context_after_encode(s, s->thread_context[i], i == context_count - 1);
>      }
>      emms_c();
>      return 0;
> -- 
> 2.23.0

this looks a bit unexpected
is there a reason why the code that writes the RST is not skipped ? if it is
doing one too much ?

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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