ffprobe | simple ffprobe wrapper | Wrapper library

The input file should be redirected into the loop rather than the sort command.

Fixed, I was missing a tile image png file

you can add quotes around the file in format string like this:"

Use another function to save you from the double indirection in a single command (parallel executes youtube-dl that executes avtomp4conv). GNU parallel uses your current shell to execute its commands, so no need for bash -c here.

What type is the ffmpegcmd variable? Is it a string or a list/sequence?

Note that Windows and Linux/POSIX behave differently with the shell=True parameter enabled or disabled. It matters whether ffmpegcmd is a string or a list.

Direct excerpt from the documentation:

On POSIX with shell=True, the shell defaults to /bin/sh. If args is a string, the string specifies the command to execute through the shell. This means that the string must be formatted exactly as it would be when typed at the shell prompt. This includes, for example, quoting or backslash escaping filenames with spaces in them. If args is a sequence, the first item specifies the command string, and any additional items will be treated as additional arguments to the shell itself. That is to say, Popen does the equivalent of:

Popen(['/bin/sh', '-c', args[0], args[1], ...])

On Windows with shell=True, the COMSPEC environment variable specifies the default shell. The only time you need to specify shell=True on Windows is when the command you wish to execute is built into the shell (e.g. dir or copy). You do not need shell=True to run a batch file or console-based executable.

Tricky one this seemed at first. I wondered if this old FFmpeg trac ticket might hold the key:

There is no stream order in mpeg-ps. what you see from ffmpeg output order is likely just if a audio or video packet comes first

But that's not actually the problem; however it is worth noting that your file has a .mpg extension, when you should be trying to output an MP4 or MKV. ".mpg" is only valid if it contains legacy MPEG-1 and MPEG-2 formats. H.264 or AAC elementary streams are invalid.

If you've not created this file yourself, it's either a mislabelled container (e.g. MKV or MP4), or someone has bizarrely muxed the streams to .mpg. Note how FFmpeg warns you of the incompatible codec during your stream reorder attempt.

MPEG-PS is a packetised format, so there's no elementary streams as such. If it's genuinely an MPEG-PS file, it may be that an audio sample appears first. Either way, you should abandon using .mpg for your formats.

See the end of this answer for how you can use FFprobe to fairly accurately identify the actual container format.

I had another think, and finally a neuron reminded me about how the -map output follows the order of assignment.

An important thing to note is that -map 0:v -map 0:a doesn't quite work how you might expect it with files containing more than one of a stream type, as that syntax matches all applicable streams of that type.

Gyan has clarified that if you have a file with exactly one video and one audio stream, -map 0:v -map 0:a will function equivalently to -map 0:1 -map 0:0.

If you want to use the 0:a syntax, if you have more than one audio for example you must address them individually, otherwise FFmpeg will group them when reordering. -map 0:a will move both audios; -map 0:a:0 will move just the first audio.

The alternative, remembering to always check stream order in every file you manipulate, is to specify absolute stream numbers in the order you wish to have them in the output. So, -map 0:1 -map 0:0 if your video is the second of two streams in the source file.

For files with one video and one audio stream, you can use either method.

I created an .MP4 file containing one H.264 video as stream 0:0 and one MP3 audio as stream 0:1.

Original file:

You may use shlex.split or put the arguments to FFprobe in a list.

In Windows OS, you can use sp.run(f'ffprobe {video}' ...
In Linux and Mac, Python tries to execute the command as file name with spaces.
For example: 'ffprobe vid.mp4' is considered a single executable command (file name with space).

You may use an arguments list:
sp.run(['ffprobe', f'{video}']...

Or use shlex.split for splitting the shell command to a list:
sp.run(shlex.split(f'ffprobe {video}'))...

For simple parsing FFprobe output in Python:

• Execute ffprobe with -of json argument, and get the output in JSON format.
• Convert the output string to dictionary using json.loads.

Here is a code sample that reads the output of FFprobe into a dictionary:

File attributes must match, but they are different. See a list of attributes that must match for proper concatenation.

Important incongruities:

• H.264 profiles (High vs Constrained Baseline)
• Timebase (16384 tbn vs 30k tbn)
• And one is has audio while the other does not

This method is good if you need to add a short segment to a long video. It will leave the long video untouched and therefore will preserve the quality and it will be fast. Downside is that you have to make sure all of the attributes match which can be difficult if you are unfamiliar with this topic.

Example to make static.mp4 like 0.mp4, using anullsrc filter to generate blank/silent/dummy/filler audio.

1. Re-encode:

That's because your Windows terminal reads system's PATH or has otherwise defined path to the ffprobe. When you run Popen with shell=True it runs the execution through shell that might or might not (your case) have access to that PATH.

Possible solutions:

1. Provide full path to ffprobe (easiest):