[FFmpeg-devel] [PATCH] avdevice/decklink: add option to drop frames till timecode is seen

[Ilinca Tudose]

This also works when passing the -format_code parameter.

On Wed, Nov 13, 2019 at 7:04 PM Ilinca Tudose <ilincat at google.com> wrote:

> My previous email was incorrect about "-wait_for_tc 1". The 2 commands
> used were:
>
> (1)
> ffmpeg -loglevel trace  -timecode_format rp188any  -wait_for_tc 1 -f
> decklink -probesize 15M -analyzeduration 5M -i "DeckLink Quad (1)" -t 30
> -preset veryfast output.mov
>
> (2)
> ffmpeg -loglevel trace  -timecode_format rp188any  -wait_for_tc 1 -f
> decklink -i "DeckLink Quad (1)" -t 30 -preset veryfast output.mov
>
> The second command is the one that produced 1 frame offset in 3 of the
> captures. The first command had 0 frames offset for all files tried.
>
> On Wed, Nov 13, 2019 at 6:30 PM Ilinca Tudose <ilincat at google.com> wrote:
>
>> Hi,
>>
>> We tested this with several types of tapes. The results are as follows:
>>
>> Out of 58 captures on Betacam tapes 55 had 0 frame offset and 3 had an
>> offset of 1 frame. All 3 were captured using the flag "-wait_for_tc 1".
>> Out of the 58 captures roughly half were captured with and half without "-wait_for_tc
>> 1".
>>
>> Out of 26 HDCAM captures (50/50 with/without "-wait_for_tc 1") all 26
>> had 0 TC offset.
>>
>> Let me know if there's any questions re testing. The testing setup is the
>> same as previously mentioned.
>>
>> Thanks,
>> ilinca
>>
>> On Wed, Nov 13, 2019 at 5:40 PM Gyan <ffmpeg at gyani.pro> wrote:
>>
>>> As suggested in the review of an earlier patch*, this one drops frames
>>> till a TC is seen.
>>>
>>> Testing results to follow.
>>>
>>> Thanks,
>>> Gyan
>>>
>>> *https://patchwork.ffmpeg.org/patch/14081/
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>>
>>
>>
>>
>
> --
>
> ---
> Ilinca Tudose | Technical Solutions Consultant, Digitization Operations |
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-- 

---
Ilinca Tudose | Technical Solutions Consultant, Digitization Operations |
go/digitops <https://goto.google.com/digitops>
Google Germany GmbH
Erika-Mann-Str. 33
80636 München

Registergericht und -nummer: Hamburg, HRB 86891

Sitz der Gesellschaft: Hamburg

Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Diese E-Mail ist
vertraulich. Wenn Sie nicht der richtige Adressat sind, leiten Sie diese
bitte nicht weiter, informieren Sie den Absender und löschen Sie die E-Mail
und alle Anhänge. Vielen Dank. This e-mail is confidential. If you are not
the right addressee please do not forward it, please inform the sender, and
please erase this e-mail including any attachments. Thanks. Der Inhalt
dieser E-Mail spiegelt den derzeitigen Stand der Verhandlungen wider und
dient als Basis für weitere Gespräche. Er soll keine rechtlich verbindliche
Verpflichtung begründen. Eine solche Verpflichtung wird allein durch einen
zwischen allen beteiligten Parteien abgeschlossenen, schriftlichen Vertrag
geschaffen. The above terms reflect a potential business arrangement, are
provided solely as a basis for further discussion, and are not intended to
be and do not constitute a legally binding obligation. No legally binding
obligations will be created, implied, or inferred until an agreement in
final form is executed in writing by all parties involved.