Different MD5 hashes for identical tracks

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Different MD5 hashes for identical tracks

raistlin.mlists
Hello Ffmpeg-user,

There are 2 sample m2ts files (about 84 MB each):
https://mir.cr/0Y8ROTYT (1)
https://mir.cr/RFI1MNOM (2)

Stream a:5 in (1) and stream a:4 in (2) are identical (being binary
compared). Though ffmpeg reports they have different MD5 hashes:

ffmpeg -loglevel 4 -i 00001.m2ts -map 0:a:5 -codec copy -f md5 -
MD5=cee9775826b81d395c7d012e69309270

ffmpeg -loglevel 4 -i 00000.m2ts  -map 0:a:4 -codec copy -f md5 -
MD5=32ccb6d7af46bfdd2100cd68c7622171

MD5 hashes for these streams being decoded (without '-codec copy') are
also different.

How could it be?

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Re: Different MD5 hashes for identical tracks

Reindl Harald


Am 30.06.20 um 18:31 schrieb [hidden email]:

> Hello Ffmpeg-user,
>
> There are 2 sample m2ts files (about 84 MB each):
> https://mir.cr/0Y8ROTYT (1)
> https://mir.cr/RFI1MNOM (2)
>
> Stream a:5 in (1) and stream a:4 in (2) are identical (being binary
> compared). Though ffmpeg reports they have different MD5 hashes:
>
> ffmpeg -loglevel 4 -i 00001.m2ts -map 0:a:5 -codec copy -f md5 -
> MD5=cee9775826b81d395c7d012e69309270
>
> ffmpeg -loglevel 4 -i 00000.m2ts  -map 0:a:4 -codec copy -f md5 -
> MD5=32ccb6d7af46bfdd2100cd68c7622171
>
> MD5 hashes for these streams being decoded (without '-codec copy') are
> also different.
>
> How could it be

most files have timestamps inside
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Re: Different MD5 hashes for identical tracks

raistlin.mlists
Hello Reindl,

>> There are 2 sample m2ts files (about 84 MB each):
>> https://mir.cr/0Y8ROTYT (1)
>> https://mir.cr/RFI1MNOM (2)
>>
>> Stream a:5 in (1) and stream a:4 in (2) are identical (being binary
>> compared). Though ffmpeg reports they have different MD5 hashes:
>>
>> ffmpeg -loglevel 4 -i 00001.m2ts -map 0:a:5 -codec copy -f md5 -
>> MD5=cee9775826b81d395c7d012e69309270
>>
>> ffmpeg -loglevel 4 -i 00000.m2ts  -map 0:a:4 -codec copy -f md5 -
>> MD5=32ccb6d7af46bfdd2100cd68c7622171
>>
>> MD5 hashes for these streams being decoded (without '-codec copy') are
>> also different.
>>
>> How could it be

> most files have timestamps inside

Are these timestamps removed by demuxing? As I wrote demuxed tracks
are byte-to-byte identical.

--
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[hidden email]

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Re: Different MD5 hashes for identical tracks

Reindl Harald


Am 30.06.20 um 20:51 schrieb [hidden email]:

> Hello Reindl,
>
>>> There are 2 sample m2ts files (about 84 MB each):
>>> https://mir.cr/0Y8ROTYT (1)
>>> https://mir.cr/RFI1MNOM (2)
>>>
>>> Stream a:5 in (1) and stream a:4 in (2) are identical (being binary
>>> compared). Though ffmpeg reports they have different MD5 hashes:
>>>
>>> ffmpeg -loglevel 4 -i 00001.m2ts -map 0:a:5 -codec copy -f md5 -
>>> MD5=cee9775826b81d395c7d012e69309270
>>>
>>> ffmpeg -loglevel 4 -i 00000.m2ts  -map 0:a:4 -codec copy -f md5 -
>>> MD5=32ccb6d7af46bfdd2100cd68c7622171
>>>
>>> MD5 hashes for these streams being decoded (without '-codec copy') are
>>> also different.
>>>
>>> How could it be
>
>> most files have timestamps inside
>
> Are these timestamps removed by demuxing? As I wrote demuxed tracks
> are byte-to-byte identical

you use diff?
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Re: Different MD5 hashes for identical tracks

raistlin.mlists
Hello Reindl,

Tuesday, June 30, 2020, 9:58:33 PM, you wrote:



> Am 30.06.20 um 20:51 schrieb [hidden email]:
>> Hello Reindl,
>>
>>>> There are 2 sample m2ts files (about 84 MB each):
>>>> https://mir.cr/0Y8ROTYT (1)
>>>> https://mir.cr/RFI1MNOM (2)
>>>>
>>>> Stream a:5 in (1) and stream a:4 in (2) are identical (being binary
>>>> compared). Though ffmpeg reports they have different MD5 hashes:
>>>>
>>>> ffmpeg -loglevel 4 -i 00001.m2ts -map 0:a:5 -codec copy -f md5 -
>>>> MD5=cee9775826b81d395c7d012e69309270
>>>>
>>>> ffmpeg -loglevel 4 -i 00000.m2ts  -map 0:a:4 -codec copy -f md5 -
>>>> MD5=32ccb6d7af46bfdd2100cd68c7622171
>>>>
>>>> MD5 hashes for these streams being decoded (without '-codec copy') are
>>>> also different.
>>>>
>>>> How could it be
>>
>>> most files have timestamps inside
>>
>> Are these timestamps removed by demuxing? As I wrote demuxed tracks
>> are byte-to-byte identical

> you use diff?
> _______________________________________________
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> https://ffmpeg.org/mailman/listinfo/ffmpeg-user

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> [hidden email] with subject "unsubscribe".

Yes. You can try yourself, that's why I gave the links.

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[hidden email]

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Re: Different MD5 hashes for identical tracks

Reindl Harald


Am 30.06.20 um 21:17 schrieb [hidden email]:

>>>>> There are 2 sample m2ts files (about 84 MB each):
>>>>> https://mir.cr/0Y8ROTYT (1)
>>>>> https://mir.cr/RFI1MNOM (2)
>>>>>
>> you use diff?
>> _______________________________________________
>> ffmpeg-user mailing list
>> [hidden email]
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
>> To unsubscribe, visit link above, or email
>> [hidden email] with subject "unsubscribe".
>
> Yes. You can try yourself, that's why I gave the links

are you mentally ill or why do you think someone goes through all that
fuckup of your links enable javasript for half of the world when you
just xould do "diff -uNr a b > diff.diff" and post the result as
plaintext on a service which don#t require shields down?
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Re: Different MD5 hashes for identical tracks

raistlin.mlists
Hello Reindl,

Tuesday, June 30, 2020, 10:23:54 PM, you wrote:

> are you mentally ill

No why? It's probably just you who can't read. Yes I used diff and it
says files are identical.

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Re: Different MD5 hashes for identical tracks

Moritz Barsnick
In reply to this post by raistlin.mlists
On Tue, Jun 30, 2020 at 19:31:24 +0300, [hidden email] wrote:
> There are 2 sample m2ts files (about 84 MB each):
> https://mir.cr/0Y8ROTYT (1)
> https://mir.cr/RFI1MNOM (2)
>
> Stream a:5 in (1) and stream a:4 in (2) are identical (being binary
> compared). Though ffmpeg reports they have different MD5 hashes:
>
> ffmpeg -loglevel 4 -i 00001.m2ts -map 0:a:5 -codec copy -f md5 -
> MD5=cee9775826b81d395c7d012e69309270

    Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
    Stream #0:1[0x1100](rus): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 384 kb/s
    Stream #0:2[0x1101](rus): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 448 kb/s
    Stream #0:3[0x1102](rus): Audio: dts (DTS) ([130][0][0][0] / 0x0082), 48000 Hz, 5.1(side), fltp, 1536 kb/s
    Stream #0:4[0x1103](eng): Audio: truehd (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), s32 (24 bit)
    Stream #0:5[0x1103]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 640 kb/s
    Stream #0:6[0x1104](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 192 kb/s

> ffmpeg -loglevel 4 -i 00000.m2ts  -map 0:a:4 -codec copy -f md5 -
> MD5=32ccb6d7af46bfdd2100cd68c7622171

    Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
    Stream #0:1[0x1100](eng): Audio: truehd (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), s32 (24 bit)
    Stream #0:2[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 640 kb/s
    Stream #0:3[0x1101](rus): Audio: dts (DTS) ([130][0][0][0] / 0x0082), 48000 Hz, 5.1(side), fltp, 1536 kb/s
    Stream #0:4[0x1102](rus): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 640 kb/s
    Stream #0:5[0x1103](ukr): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 448 kb/s

192 kb/s stereo vs. 448 kb/s stereo.
They can't be identical, can they?

Moritz
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Re: Different MD5 hashes for identical tracks

Reindl Harald
In reply to this post by raistlin.mlists


Am 30.06.20 um 21:54 schrieb [hidden email]:
> Hello Reindl,
>
> Tuesday, June 30, 2020, 10:23:54 PM, you wrote:
>
>> are you mentally ill
>
> No why? It's probably just you who can't read. Yes I used diff and it
> says files are identical

if they are identical they have the same checksum
it's that easy

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Re: Different MD5 hashes for identical tracks

raistlin.mlists
In reply to this post by Moritz Barsnick
Hello Moritz,

Tuesday, June 30, 2020, 11:12:13 PM, you wrote:

> 192 kb/s stereo vs. 448 kb/s stereo.
> They can't be identical, can they?

I got it now. I defined stream numbers using tsMuxer and considered
TrueHD stream with embedded AC3 stream as one stream while ffmpeg
considers them as two separate streams.
Thanks!

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