[FFmpeg-user] framecrc

[Mark Filipak]

Previous Subject: "rewrite tags in a source's PES headers -- How?"

On 11/11/23 13:41, Paul B Mahol wrote:
> On Sat, Nov 11, 2023 at 7:29 PM Mark Filipak <markfilipak.imdb at gmail.com>
> wrote:
> 
>> Here's what I'm doing:
>> -bsf:v setts=time_base=1/24000:pts=N*1001:dts=N*1001
>>
>> Here's the result:
>> frame  pts                        dts
>>  0        0                       2002 <= should be     0
>>  1     3003 <= should be  1001    3003 <= should be  1001
>>  2     4004 <= should be  2002    4004 <= should be  2002
>>  3     2002 <= should be  3003    5005 <= should be  3003
>>  4     5005 <= should be  4004    6006 <= should be  4004
>>  5     1001 <= should be  5005    7007 <= should be  5005
>>  6     8008 <= should be  6006    8008 <= should be  6006
>>  7     9009 <= should be  7007    9009 <= should be  7007
>>  8     7007 <= should be  8008   10010 <= should be  8008
>>  9    10010 <= should be  9009   11011 <= should be  9009
>> 10     6006 <= should be 10010   12012 <= should be 10010
>> 11    13013 <= should be 11011   13013 <= should be 11011
>> 12    12012 <= should be 12012   14014 <= should be 12012
>> 13    14014 <= should be 13013   15015 <= should be 13013
>> 14    11011 <= should be 14014   16016 <= should be 14014
>> 15    17017 <= should be 15015   17017 <= should be 15015
>> 16    18018 <= should be 16016   18018 <= should be 16016
>>
>> The source video is 'NTSC'-soft.
>> Can this be explained?
>> Can it be countered?
>>
>> PTSs in frames 1..5 are +2 +2 -1 +1 -4
>> PTSs in frames 6..10 are +2 +2 -1 +1 -4
>> PTSs in frames 11..15 are +2 +0 +1 -3 +2
>> I'm baffled.
>>
> 
> N is packet number, and it goes in different order.

Oh, yes, out of order/out of sequence.

> Can be confirmed with:
> 
> ffmpeg -i <video> -c copy -f framecrc -

Thank you, Paul. Good of you. How do I interpret the framecrc table?

stream_index                      packet_duration
|  packet_dts                     |     packet_size
|  |          packet_pts          |     |      0xCRC
|  |________  |_________________  |___  |____  |_________
1          0                   0  2880    768  0xb16c8010
1       2880                2880  2880    768  0x1b728309
1       5760                5760  2880    768  0x966977f8
1       8640                8640  2880    768  0x6e078511
0      10878               22890  3003  62500  0x5877c6d3
1      11520               11520  2880    768  0xe49b880c
[framecrc@ 0000000002a9b140] Timestamps are unset ... stream 0 ...
1      14400               14400  2880    768  0x0a217046
0      15382               15382  3003  18300  0xd4f063a2  F=0x0
1      17280               17280  2880    768  0xc13a7e27
0      18385               18385  4504  17924  0x14ae7839  F=0x0
1      20160               20160  2880    768  0x91017a25
0      22890  0x8000000000000000  4504  37160  0xa54ad420  F=0x0
1      23040               23040  2880    768  0xcd087be2
0      25893               25893  4504  18920  0x6230931b  F=0x0
1      25920               25920  2880    768  0xca8a79b6
1      28800               28800  2880    768  0x1d5e7a84
0      30398               30398  3003  17172  0xebbc5af9  F=0x0
1      31680               31680  2880    768  0x1c3e7f7d
0      33401  0x8000000000000000  3003  33636  0x2bf50e31  F=0x0
1      34560               34560  2880    768  0x815d7b63
1      37440               37440  2880    768  0x1ac6762d
0      37905               37905  3003  16144  0x5fabbc96  F=0x0
1      40320               40320  2880    768  0x7e2f8d29
0      40908               40908  4504  14960  0xe0a8abb9  F=0x0
1      43200               43200  2880    768  0x951c8f4c
0      45412  0x8000000000000000  4504  34072  0x6bf61d8c  F=0x0
1      46080               46080  2880    768  0xf42e82a7
0      48415               48415  4504  14788  0xcc5c4f38  F=0x0
:          :                   :     :      :           :
0  136171401           136171401  3003  23924  0xe65b80f5  F=0x0
1  136172160           136172160  2880    768  0x3b687c8c
0  136174404  0x8000000000000000  3003  52328  0x7a17da08  F=0x0
0  136178908           136178908  3003  23932  0x5bee6d60  F=0x0
0  136181911           136181911  4504  23452  0xc4a6eb3a  F=0x0

Why is the above so different from the packets VOBEdit shows and that I manually parse?
I thought all VOB packets were 2048 bytes.
Are the packets above a different type of packet?

The video is 'NTSC'-soft (24/1.001fps). '3003' means ffprobe 'sees' 30/1.001fps.
How can I stop the decoder doing telecine?

Cheers
--Mark.