[FFmpeg-user] Using amerge to convert dual mono to stereo
tim.nicholson at bbc.co.uk
Fri Jan 13 10:27:47 CET 2012
On 13/01/12 07:59, Tim Nicholson wrote:
> On 12/01/12 18:01, Nicolas George wrote:
>> Le tridi 23 nivôse, an CCXX, Tim Nicholson a écrit :
>>> I am trying to use the amerge filter to convert dual mono to stereo,
>>> but get a warning from amerge:-
>>> "[amerge @ 0x1933a80] Inputs overlap: output layout will be meaningless"
>>> and sure enough what I get is stream 1 on both channels of the
>>> stereo output with no stream 2 at all....
> Well what I wanted was the first mono stream to be left and the second
> mono stream to be right. What I got was the first mono stream on both
Running again (with simpler parameters) and looking at the console
output when I ran it I notice the following:-
[amovie @ 0x1791e80] seek_point:0 format_name:(null)
[amovie @ 0x17f8fc0] seek_point:0 format_name:(null)
[amerge @ 0x17f9a60] Inputs overlap: output layout will be meaningless
This is presumably because they are both flagged as "mono" rather than
"left" and "right"
[abuffersink @ 0x1791e00] auto-inserting filter 'auto-inserted aconvert
0' between the filter 'Parsed_amerge_2' and the filter 'out'
[amerge @ 0x17f9a60] in1:mono + in2:mono -> out:stereo
That is what I would expect. based on the docs saying:-
"If the channel layouts of the inputs are not disjoint, the output will
have all the channels of the first input then all the channels of the
second input, in that order", and what I want
However the next line is:-
[aconvert @ 0x17ef2e0] fmt:s32 cl:stereo planar:0 -> fmt:s16 cl:mono
This last line suggests that aconvert is being invoked automatically
and turning the stereo back into mono which is not what is wanted. The
question is why, and how to avoid it?
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