Mailing List Archive

at dusk with the light behind it may very well pass for OnT
I have a recording (not mythtv) that has missing or broken headers or time stamps).
I was looking for a way to test and Klaus posted a solution, for some other problem, that worked for me.
I thought his post was

ffmpeg -i Channel1.20Jan2022.130000.mp4 -vcodec copy -acodec copy junk.mp4

but not quite. Spelunking the man does not enlighten, and I can’t find that post.
Please any suggestions
James
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Re: at dusk with the light behind it may very well pass for OnT [ In reply to ]
On Thu, Jan 20, 2022 at 2:12 AM James Linder <jam@tigger.ws> wrote:

> I have a recording (not mythtv) that has missing or broken headers or time
> stamps).
> I was looking for a way to test and Klaus posted a solution, for some
> other problem, that worked for me.
> I thought his post was
>
> ffmpeg -i Channel1.20Jan2022.130000.mp4 -vcodec copy -acodec copy junk.mp4
>
> but not quite. Spelunking the man does not enlighten, and I can’t find
> that post.
> Please any suggestions
> James
>
>
Hi James,

I did a bit of searching; been on the list aaaages and have all of it saved
in my gmail since ... over a decade now. Late 2011 when I was initially
trying to setup a mythbox to record OTA for my mother.. Project was never
realized due to multiple issues of antenna and computer placement, and
being rather too far away from broadcast towers to not need some sort of
rotation on high gain directional antennas due to the variety of locations
we have broadcasting some stuff here in Denver.
Since then she passed on, yet i stay subbed since I at one point want to
try again.

To the meat of it:
Seems back in November 22-23 of 2017 in a thread titled '[mythtv-users]
video and container woes' you were having issues with an mpeg transport
stream .ts file, and the ffmpeg command to shove it into a normal mpeg
container rewriting the metadata bits was:

mythffmpeg -i /store/1017_20171001114200.ts -acodec copy -vcodec copy
-scodec copy -aspect 16:9 /store/Movies/DM8x01.mpg
[.merging together a few different replies to get all the different codec
copy bits, scodec is for subtitles, which may or may not be present in a
file]

Since you are now starting with an mp4 file, outputting to a .mpg probably
doesnt make sense, you might just leave the output filename as .mp4 or
perhaps .mkv since the MKV container format is far more forgiving of any
sort of weirdness from the component streams, recording or file errors, and
other oddities than mp4 can be. ffmpeg can put the component
streams(audio,video,subs) into whatever container you specify if it
supports it (wouldnt make sense for vorbis audio in an mpg or mp4 stream,
but you can put h264/vp9/mpeg2/etc and opus/vorbis/flac/wav/etc into an mkv
and it works. Its basically a universal container format :)

In your case today, if you have the mkvtoolnix package installed, I wonder
if using a command like:
mkvmerge -o output.mkv Channel1.20Jan2022.130000.mp4
might do a similar job of making it play better? Worth a try IMHO and
perhaps simpler in the future. I find MKV files to be rather well
supported nowadays on a lot of devices.

Hope this helps!

Mike
Re: at dusk with the light behind it may very well pass for OnT [ In reply to ]
On 20/01/2022 09:09, James Linder wrote:
> I have a recording (not mythtv) that has missing or broken headers or time stamps).
> I was looking for a way to test and Klaus posted a solution, for some other problem, that worked for me.
> I thought his post was
>
> ffmpeg -i Channel1.20Jan2022.130000.mp4 -vcodec copy -acodec copy junk.mp4
>
> but not quite. Spelunking the man does not enlighten, and I can’t find that post.
> Please any suggestions
> James

Resending to list

This is my current favourite:

mythffmpeg -hide_banner -ignore_unknown -i infile.ts -vcodec copy
-acodec copy -avoid_negative_ts make_zero -f mpegts outfile.ts

If you have/want mp4 adjust the extensions and -f * as seems fit. I
think the -avoid_negative_ts make_zero parts are really for
concatenation, but I've usually found it hard to predict what ffmpeg
will give.

Droll subject lines are fine but don't help searches...

Cheers

John

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Re: at dusk with the light behind it may very well pass for OnT [ In reply to ]
> On 20 Jan 2022, at 7:16 pm, John Pilkington <johnpilk222@gmail.com> wrote:
>
> This is my current favourite:
>
> mythffmpeg -hide_banner -ignore_unknown -i infile.ts -vcodec copy -acodec copy -avoid_negative_ts make_zero -f mpegts outfile.ts
>
> If you have/want mp4 adjust the extensions and -f * as seems fit. I think the -avoid_negative_ts make_zero parts are really for concatenation, but I've usually found it hard to predict what ffmpeg will give.
>
> Droll subject lines are fine but don't help searches...

The droll subject line was half apology. OT because it was in the list in the last month or so. OffT because my query does not relate. But thanks
James

BTW Klaus’ comment is hidden by a non-obvious subject line.
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Re: at dusk with the light behind it may very well pass for OnT [ In reply to ]
On 20/01/2022 11:16, John Pilkington wrote:
> On 20/01/2022 09:09, James Linder wrote:
>> I have a recording (not mythtv) that has missing or broken headers or
>> time stamps).
>> I was looking for a way to test and Klaus posted a solution, for some
>> other problem, that worked for me.
>> I thought his post was
>>
>> ffmpeg -i Channel1.20Jan2022.130000.mp4 -vcodec copy -acodec copy
>> junk.mp4
>>
>> but not quite. Spelunking the man does not enlighten, and I can’t find
>> that post.
>> Please any suggestions
>> James
>
> Resending to list
>
> This is my current favourite:
>
> mythffmpeg -hide_banner -ignore_unknown  -i infile.ts  -vcodec copy
> -acodec copy -avoid_negative_ts make_zero -f mpegts  outfile.ts
>
> If you have/want mp4 adjust the extensions and -f * as seems fit.  I
> think the -avoid_negative_ts make_zero parts are really for
> concatenation, but I've usually found it hard to predict what ffmpeg
> will give.
>
> Droll subject lines are fine but don't help searches...

Hmm. It looks as if I didn't quote the line I intended. This one gets
used much more often, on this box, after demux of mpeg2 video by
Project-X, which also corrects a/v sync. It does include timestamp
stuff that might be helpful.

{{{

mythffmpeg -hide_banner -ignore_unknown -fflags +genpts -i infile.m2v -i
infile.mp2 -vcodec copy -acodec copy -f mpegts outfile.ts

}}}
>
> Cheers
>
> John
>

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