[FFmpeg-user] Showinfo bug?

[Mark Filipak]

On 03/04/2020 06:51 AM, Paul B Mahol wrote:
> On 3/4/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>> 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.
> 
> It is 29.97 after soft telecined being applied.

Yes, I know. To confirm (to be sure) I have 2 choices:
1, Believe that MPV is reporting what I *think* it's reporting, or
2, Read the metadata (that should show soft telecining) but I'm not sure 
that I can rely on ff* to report metadata because ff* seems to have it's 
own definition of what metadata is (and it's different from what is 
defined as metadata in H.262).