Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
 help / color / mirror / Atom feed
From: Leo Izen <leo.izen@gmail.com>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH 2/3] avcodec/j2kenc: Add alpha support
Date: Thu, 6 Apr 2023 10:15:48 -0400
Message-ID: <ee5e0d0c-c0f6-b2a5-8f9d-02ed2e468737@gmail.com> (raw)
In-Reply-To: <20230402213429.GO1164690@pb2>



On 4/2/23 17:34, Michael Niedermayer wrote:
> On Fri, Mar 31, 2023 at 01:14:40AM +0200, Michael Niedermayer wrote:
>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
>> ---
>>   libavcodec/j2kenc.c | 28 ++++++++++++++++++----------
>>   1 file changed, 18 insertions(+), 10 deletions(-)
>>
>> diff --git a/libavcodec/j2kenc.c b/libavcodec/j2kenc.c
>> index 97b0da1c976..b23fb73770a 100644
>> --- a/libavcodec/j2kenc.c
>> +++ b/libavcodec/j2kenc.c
>> @@ -320,8 +320,8 @@ static int put_siz(Jpeg2000EncoderContext *s)
>>   
>>       for (i = 0; i < s->ncomponents; i++){ // Ssiz_i XRsiz_i, YRsiz_i
>>           bytestream_put_byte(&s->buf, s->cbps[i] - 1);
>> -        bytestream_put_byte(&s->buf, i?1<<s->chroma_shift[0]:1);
>> -        bytestream_put_byte(&s->buf, i?1<<s->chroma_shift[1]:1);
>> +        bytestream_put_byte(&s->buf, (i%3)?1<<s->chroma_shift[0]:1);
>> +        bytestream_put_byte(&s->buf, (i%3)?1<<s->chroma_shift[1]:1);
> 
> i will replace the %3 by +1&2 to avoid slow modulo before applying
> 
> 

(i % 3) and (i + 1) & 2 aren't the same tho, and won't be nonzero at the 
same time. `(i + 1) & 2` is equivalent to `(i + 1) % 4`.

- Leo Izen (thebombzen)

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

  parent reply	other threads:[~2023-04-06 14:16 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-30 23:14 [FFmpeg-devel] [PATCH 1/3] avcodec/j2kenc: Add forgotten yuv440 variants Michael Niedermayer
2023-03-30 23:14 ` [FFmpeg-devel] [PATCH 2/3] avcodec/j2kenc: Add alpha support Michael Niedermayer
2023-04-02 21:34   ` Michael Niedermayer
2023-04-05 12:50     ` Tomas Härdin
2023-04-05 23:36       ` Michael Niedermayer
2023-04-06 14:15     ` Leo Izen [this message]
2023-04-06 19:18       ` Michael Niedermayer
2023-03-30 23:14 ` [FFmpeg-devel] [PATCH 3/3] [RFC] Remove libopenjpegenc Michael Niedermayer
2023-03-30 23:26   ` Pierre-Anthony Lemieux
2023-03-30 23:31   ` Michael Bradshaw
2023-04-01 23:37     ` Stefano Sabatini
2023-04-05 12:55   ` Tomas Härdin
2023-04-12  1:48     ` Pierre-Anthony Lemieux
2023-04-02 21:24 ` [FFmpeg-devel] [PATCH 1/3] avcodec/j2kenc: Add forgotten yuv440 variants Michael Niedermayer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ee5e0d0c-c0f6-b2a5-8f9d-02ed2e468737@gmail.com \
    --to=leo.izen@gmail.com \
    --cc=ffmpeg-devel@ffmpeg.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://master.gitmailbox.com/ffmpegdev/0 ffmpegdev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 ffmpegdev ffmpegdev/ https://master.gitmailbox.com/ffmpegdev \
		ffmpegdev@gitmailbox.com
	public-inbox-index ffmpegdev

Example config snippet for mirrors.


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git