[FFmpeg-devel] [PATCH v3] ffmpeg: add option -isync

Gyan Doshi ffmpeg at gyani.pro
Sat Jul 9 21:27:49 EEST 2022



On 2022-07-08 09:26 am, Gyan Doshi wrote:
>
>
> On 2022-07-07 03:11 pm, Anton Khirnov wrote:
>> Quoting Gyan Doshi (2022-07-04 18:29:12)
>>> This is a per-file input option that adjusts an input's timestamps
>>> with reference to another input, so that emitted packet timestamps
>>> account for the difference between the start times of the two inputs.
>>>
>>> Typical use case is to sync two or more live inputs such as from 
>>> capture
>>> devices. Both the target and reference input source timestamps 
>>> should be
>>> based on the same clock source.
>>>
>>> If not all inputs have timestamps, the wallclock times at the time of
>>> reception of inputs shall be used. FFmpeg must have been compiled with
>>> thread support for this last case.
>> I'm wondering if simply using the other input's InputFile.ts_offset
>> wouldn't achieve the same effect with much less complexity.
>
> That's what I initially did. But since the code can also use two other 
> sources for start times (start_time_realtime, first_pkt_wallclock),
> those intervals may not exactly match the difference between 
> fmctx->start_times so I use a generic calculation.

Plan to push on Monday, if no further changes. 5.1 is to be cut soon.

Regards,
Gyan


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