convert and join in ffmpeg

[jack616]

I have some video files I need to convert and join
I can do all tasks individually but I can't work out how
to get ffmpeg to do all tasks in one go.

Job example:
1 have 3 video files in MKV format H264 video and mpeg2 audio
I want to convert the audio of each to AC3 640K
And join all 3 files to make one single playable .TS file.

I know how to convert the audio and to make the result a .TS for individual files
but I can't work out how to do that and join them all in one go.
At the moment I have to convert each file and then join them in TSmuxer
which I shouldn't need to do.

Can anyone help?

[pandy]

https://trac.ffmpeg.org/wiki/Concatenate

[jack616]

Thanks for the link pandy - I've been using the ffmpeg doc pages but this link seems to make things
a bit clearer - I'll give it another go.

[jack616]

nope - still problems

This is what I am trying - I've based that on pandy's link "concat of files with different codecs" example:

ffmpeg -i fred.mkv -i jim.mkv -i sheila.mkv -filter_complex '[0:v:0] [0:a:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] concat=n=3:v=1:a=1 [v] [a]'
-map '[v]' -map '[a]' output.mkv

This should be a simple concat (I've removed all conversions for simplicity but I get the same message with them)
The error is "output file #0 does not contain any stream"

I can't work out why - any suggestions?

I have tried simplifying the filter to [0:0] [0:1] [1:0][1:1] ... etc with no luck
I have also tried the -c:v copy functions but the same results (I know the wiki page says copy doesnt work with concat but I'm not sure exactly how that would apply right there - it doesnt work with or without anyway...

ps - I'm using the latest ffmpeg

[poisondeathray]

what specs are the 3 mkv files ? use mediainfo (view=>text)

[jack616]

OK progress...
It seems I have to use double quotes for all the filter options not single quotes
(In batch files or on the command line - command line PHP doesn't seem to care) - odd - MS again.
(No ^ escaping or quoting doesnt seem to work)

Anyway I can now merge and convert the audio to AC3 on the fly but immediately there is a problem.
I need the output in .TS format (or there is no point my trying to do this) but ffmpeg converts
the video stream to mpeg2 every time TS output is used.
I just want it to leave the video alone.

Since the copy function can't be used with filters does anyone know how I can stop it re-encoding the video.
(When output is to MKV it does leave it alone but that's no use to me)
My guess is ffmpeg has a format default and re-encodes even when not asked to.

Ideally I need a way to force the video stream to just copy.

[poisondeathray]

If they are the same characteristics, you can use concat demuxer - that allows stream copy. It looks like you are using concat filter - which means you re-encode

-filter_complex and -vf mean video is decompressed, thus no stream copy is allowed

[jack616]

Ah I see - thanks poisondeathray - I didn't realise that I should be using a different filter- I'll look into it later today.

[jack616]

ok I can now complete the task but I have another issue: the concat merge filter is creating a ghost video file in mpeg2 format in addition
to the outfile.ts output
This only happens if I use a .ts extension on the output - the same command on the same files outputting to MKV does not do this
This "ghost file" has no filename except ".ts"

This is an issue as it slows everything down to 10fps instead of around 400fps
I have tried using -map to ensure I only get the streams I need without success

Simplifying the bare minimum also does this:
ie:
ffmpeg -f concat -i merge.lst outfile.ts
if outfile.mkv is used I do not get the ghost file

Does anyone have any suggestions?
thanks

[poisondeathray]

ok I can now complete the task but I have another issue: the concat merge filter is creating a ghost video file in mpeg2 format in addition
to the outfile.ts output
This only happens if I use a .ts extension on the output - the same command on the same files outputting to MKV does not do this
This "ghost file" has no filename except ".ts"

This is an issue as it slows everything down to 10fps instead of around 400fps
I have tried using -map to ensure I only get the streams I need without success

Simplifying the bare minimum also does this:
ie:
ffmpeg -f concat -i merge.lst outfile.ts
if outfile.mkv is used I do not get the ghost file

Does anyone have any suggestions?
thanks

Did you use -c copy as in the example on the ffmpeg concatenate page?

If it still doesn't work you can do a 2 step batch, one to mkv, one to rewrap to .ts ; or use a batch using tsmuxer, or a combination of them because you need to re-encode the audio anyways.

If that still doesn't work, post the info requested earlier on your files. Because if there are incompatibilities , you might have to re-encode at least part of the video(s)

[jack616]

Found it -

It was just an extra space in an unquoted variable causing 2 files to be output...
I'll record it here because it's a tricky one to spot being an OS dependant thing:
as a second command in a dos batch file "For " statement I had
"set variable=%%A )"
which is fixed by using
"set variable=%%A)"

The extra space is causing the output filename plus a .ts name because I was using
ffmpeg -f concat -i merge.lst %variable%.ts
Expanding a space before the .ts

I'm working up a basic batch file that does the job which I'll post later.
Be warned if you want to use it it will be designed just to do my task - you may need to add
error checking or extra quoting etc yourself

Thanks for the input though guys - it's all been helpful and I'm learning more about ffmpeg every
time something goes wrong!

P.S.
I'm doing this partly because I have some files that TSmuxer converts to .TS but also causes
them to have the dreaded "monotonous DTC" errors that didnt exist in the files before.
I'm hoping not to use TSmuxer again.

[jack616]

This works for me - but it's very simple and you will probably need to adjust things:

@echo off
REM filename: merge.bat
REM Created on windows-7 64

REM PURPOSE:  Merges all MKV files in folder into 1 file converting audio 
REM           to AC3 on fly outputting to .TS container 

REM REQUIRES: ffmpeg (recent)  Input files audio DTS or similar for conversion to AC3
rem           Known issue: PCM audio must be converted before using this 
rem           Tested only on HD H264 video with DTS audio - no other streams  
rem           If paths or filenames have spaces you will need to quote
REM USAGE NOTES:
rem           Place this batch file in folder with all MKV's to be merged.
rem           Files will be added in standard sort order
rem           Customise paths to requirements then just call "merge.bat"  
rem           DesitinationDir contains merged output 
rem           Having source dir on different drive just to speed things up
rem           improvements possible such as quoting, I/O changes filtering etc.
rem           Consider this a work in progress skeleton to customise 

rem           I hope someone finds this useful. 
rem           jack616

:INIT 
set sourcedrive=%~d0%
set sourcedir=%cd%
set destinationDir=d:^\ffmpegTemp
set workingdrive=d:
rem if not already set do (or wherever yours is stored):
rem set path=%PATH%;c:\media\ffmpeg\bin;

:START
%sourcedrive%
cd %sourcedir%
rem clean the merge list 
echo # Start > merge.lst 
REM WARNING: Keep the ')' next to the %%A in the 'set thisFile=' function or a 
rem          space is appended in output filename

for %%A in (*.mkv) do ( @echo file %%A >> merge.lst
                       set thisfile=%%A)  
                                            
echo # End merge list >> merge.lst                       
rem final output name based on last input name + .ts  rename manually as reqd.
ffmpeg -f concat -i merge.lst -acodec ac3 -ar 48000 -b:a 640k -c:v copy  %destinationDir%^\%thisfile%.ts
echo .
echo End. 
echo Output is in %destinationDir%

:END