[FFmpeg-devel] [PATCH] Limited timecode support for lavd/decklink

Kieran O Leary kieran.o.leary at gmail.com
Fri May 25 20:47:32 EEST 2018

Hi Jonathan,

On Fri, May 25, 2018 at 6:32 PM, Jonathan Morley <jmorley at pixsystem.com> wrote:
> Hi Kieran,
> To answer your question, this change basically takes the first valid TC as a string and sticks it in the video’s avstream metadata dictionary where other muxers and encoders look. It does not make an independent timecode track/stream with samples per frame. That is why I called the patch “limited”. However there doesn’t seem to be many if any parts of ffmpeg that use dedicated timecode streams with individual samples. That is why it still seemed worth submitting my work back as we move on to other solutions.

It sounds great to me! I think that this type of timecode (just
storing first value as a string string) is all I've ever really seen
in the real world(I work in the Irish Film Archive and we have several
thousand video tapes as well). This is how AJA Control Room and
Blackmagic Media Express work anyhow. I'm hoping that this will allow
open source archival capture tools like
https://github.com/amiaopensource/vrecord to be able to capture

I look forward to trying it out, as our goal is to be able to use
vrecord in order to capture tape to FFV1/Matroska. Matroska doesn't
support data tracks (yet), but ffmpeg does store the starting timecode
string as a Matroska Tag when it detects a timecode track in a source
video. I would love if capturing to Matroska from tape could store
that starting timecode value, but it's a completely seperate issue to
this patch.

> I hope that still helps you in your case. I will stay the course to address Marton’s feedback and get this in there.

yeah it's great, I'm also interested in your AJA work as we also have
AJA hardware, though as there's no open SDK for AJA, I'm not sure how
this would integrate into FFmpeg.



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