[FFmpeg-user] Showinfo bug?

[Mark Filipak]

On 03/04/2020 06:42 AM, Paul B Mahol wrote:
> On 3/4/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>> On 03/04/2020 05:34 AM, Paul B Mahol wrote:
>>> On 3/4/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>>>> On 03/04/2020 04:57 AM, Paul B Mahol wrote:
>>>>> On 3/4/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>>>>>> Is this a showinfo bug, or am I misinterpreting the results?
>>>>>>
>>>>>> For VOBs that are known to be 23.976 FPS, soft-telecined, this command:
>>>>>> 'ffprobe -f lavfi movie=VTS_01_1.VOB,showinfo'
>>>>>> reports that they're 59.94 FPS.
>>>>>>
>>>>>> The first & last lines of output show this:
>>>>>> "[Parsed_showinfo_1 @ 000001d381f6dc80] config in time_base: 1/90000,
>>>>>> frame_rate: 60000/1001"
>>>>>> "    Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 720x480
>>>>>> [SAR 1:1 DAR 3:2], 59.94 tbr, 90k tbn, 90k tbc"
>>>>>>
>>>>>> This seems to be a rather big error, if indeed it is an error. At
>>>>>> question is the reliability of ff*.
>>>>>>
>>>>>
>>>>> I trust more ff* than you.
>>>>
>>>> Paul, I trust that your answer indicates that I'm simply misinterpreting
>>>> the results.
>>>>
>>>> So, to what does "frame_rate: 60000/1001" refer?
>>>
>>> Can not guess without looking and exact same file.
>>
>> The 'file' is every 23.976 FPS, soft-telecined video I've checked. Mind
>> you, other ff* functions report them as 29.970 FPS, for example:
>>
>> "Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, smpte170m,
>> progressive), 720x480 [SAR 32:27 DAR 16:9], Closed Captions, 29.97 fps,
>> 59.94 tbr, 90k tbn, 59.94 tbc"
>>
>> whereas MPV reports "FPS: 29.970 (specified) 23.976 (estimated)".
>>
>> I have been interpreting that as meaning that ff* is reporting metadata
>> whereas MPV is reporting the actual MPEG2 stream.
>>
>> 'ffprobe -f lavfi movie=VTS_01_1.VOB,showinfo' is the only ff* function
>> that reports 60000/1001.
>>
>> 23.976 FPS? 29.97 FPS? 59.94 FPS? What am I to believe?
> 
> You should believe ffprobe output. Note that video may be VFR, and
> than all of this is meaningless.

It's not VFR. ffprobe reports 29.97 FPS, but I'm pretty sure the stream 
is actually 23.976 FPS (soft-telecined) as reported by MPV.