[FFmpeg-trac] #6645(undetermined:closed): Feature Request: Virtual Extension Parameter

[FFmpeg]

#6645: Feature Request: Virtual Extension Parameter
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             Reporter:               |                    Owner:
  thomas_johnson                     |                   Status:  closed
                 Type:  defect       |                Component:
             Priority:  normal       |  undetermined
              Version:  git-master   |               Resolution:  invalid
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by thomas_johnson):

 @cehoyos

 I really have no idea why is this closed as invalid and I have no idea
 what are you saying (probably you misunderstood the issue). You are right
 about input formats (ffmpeg detects it by content, not by extension), but
 there is no simple way to override output extension. Input format is
 determined by file content, but output format cannot be determined by file
 content, instead it is determined by extension. So, definitelly, output
 format is primarily determined by output file extension.

 But, the problem is because there is no simple way to determine which
 parameters one need to pass in order to override real extension to
 specific extension. As I said, there are a lot of exceptions (matroska for
 mkv, then singlejpeg for jpg, etc) which are not obvious and there is no
 official list which allows users to find the pattern.

 You've also said "It is even possible to force specific image formats if
 you prefer that over the image2 demuxer." - I asked the question on stack
 overflow about how to override real output extension for *any* format.
 Experts responded and answered that what I'm trying to achieve is very
 hard because there is no official way to achieve it and that ffmpeg has no
 functionality for it. Some formats are easy to override (png, bmp, mp4,
 etc.) but others have specific pattern and not obvious.

 On Stack Oveflow they suggested that I should create a feature request
 here because ffmpeg currently has no official list which connects demuxers
 with extension pattern. If I want to encode to specific extension (while
 real extension is different), there is no simple way to achieve it. I
 agree that for raw images I need to provide pixel format and similar
 details, but anyway, raw images doesn't even have official extension. But,
 I''m talking about ordinary file formats.

 I don't know if you will see this response, but in case you don't, I'll
 probably file a new request with better explanations. Ffmpeg experts from
 stack overflow know what they are talking about. I'm not ffmpeg expert and
 I just did what they suggested. Basically, there is no easy way to
 override any output extension, because ffmpeg detects output format
 primarily by its extenion. Not input format, but output format.

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Ticket URL: <https://trac.ffmpeg.org/ticket/6645#comment:3>
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