Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
 help / color / mirror / Atom feed
From: Marvin Scholz <epirat07-at-gmail.com@ffmpeg.org>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH] Playout to DeckLink will wait for all buffered frames before stopping.
Date: Tue, 08 Jul 2025 17:19:14 +0200
Message-ID: <E11760FF-196F-493C-AF7A-A217BD48AB85@gmail.com> (raw)
In-Reply-To: <CAHGibzFgLA-O5tjWLgHYTR54B-Gtx=Jr7uKJ_9HwR6hJHkumRg@mail.gmail.com>



On 8 Jul 2025, at 16:54, Devin Heitmueller wrote:

> Hi Matt,
>
> Thanks for your contribution.  Comments inline.
>
> On Mon, Jul 7, 2025 at 9:40 PM Matt via ffmpeg-devel
> <ffmpeg-devel@ffmpeg.org> wrote:
>> diff --git a/libavdevice/decklink_enc.cpp b/libavdevice/decklink_enc.cpp
>> index cb8f91730e..5751f27de8 100644
>> --- a/libavdevice/decklink_enc.cpp
>> +++ b/libavdevice/decklink_enc.cpp
>> @@ -20,6 +20,7 @@
>>   */
>>
>>  #include <atomic>
>> +#include <unistd.h>
>
> Not needed (see below)
>
>>  using std::atomic;
>>
>>  /* Include internal.h first to avoid conflict between winsock.h (used by
>> @@ -369,11 +370,26 @@ av_cold int ff_decklink_write_trailer(AVFormatContext *avctx)
>>  {
>>      struct decklink_cctx *cctx = (struct decklink_cctx *)avctx->priv_data;
>>      struct decklink_ctx *ctx = (struct decklink_ctx *)cctx->ctx;
>> +    uint32_t buffered;

Can be moved inside the while block to narrow the scope.

>>
>>      if (ctx->playback_started) {
>>          BMDTimeValue actual;
>>          ctx->dlo->StopScheduledPlayback(ctx->last_pts * ctx->bmd_tb_num,
>>                                          &actual, ctx->bmd_tb_den);
>> +        av_log(avctx, AV_LOG_DEBUG, "Stopped at %ld, requested %ld\n", actual, ctx->last_pts * ctx->bmd_tb_num);
>> +        while (1){
>> +            ctx->dlo->GetBufferedVideoFrameCount(&buffered);
>> +            if (buffered <= 0){
>> +                break;
>> +            }
>> +            av_log(avctx, AV_LOG_DEBUG, "Waiting for %d buffered frames to finish\n", buffered);
>> +            if (buffered < 5) {
>> +                usleep(1);
>> +            } else {
>> +                usleep(300);
>> +            }
>
> The sleep calls should use av_usleep(), which is portable and you
> don't need unistd.h.  Also, there should be some limit so that it
> doesn't block forever if video frames are scheduled very far in the
> future (e.g. after 1 second, give up and log a warning).
>

I think even if a frame is schedule "far" in the future, if I want them
all played out then it should probably still wait, no? As what is considered
"far" is a matter of interpretation…

Also there should likely be an option to opt in to this new behavior?

> Devin
>
> -- 
> Devin Heitmueller, Senior Software Engineer
> LTN Global Communications
> o: +1 (301) 363-1001
> w: https://ltnglobal.com  e: devin.heitmueller@ltnglobal.com
> _______________________________________________
> 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".
_______________________________________________
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".

  reply	other threads:[~2025-07-08 15:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-08  1:39 Matt via ffmpeg-devel
2025-07-08 14:54 ` Devin Heitmueller
2025-07-08 15:19   ` Marvin Scholz [this message]
2025-07-08 16:22     ` Devin Heitmueller
2025-07-08 17:08       ` Marvin Scholz
2025-07-08 17:13         ` Devin Heitmueller
2025-07-08 20:11           ` Marton Balint

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=E11760FF-196F-493C-AF7A-A217BD48AB85@gmail.com \
    --to=epirat07-at-gmail.com@ffmpeg.org \
    --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