[FFmpeg-devel] [PATCH] lavfi: dump debug graph when merging failed.

[Nicolas George]

Le duodi 12 frimaire, an CCXXII, Stefano Sabatini a écrit :
> ffplay test.wav -af volume -loglevel debug

> [auto-inserted resampler 0 @ 0x7f929c01af20] Cannot select channel layout for the link between filters auto-inserted resampler 0 and ffplay_abuffersink.

> [AVFilterGraph @ 0x7f929c017720] 0: abuffer "ffplay_abuffer"
> [AVFilterGraph @ 0x7f929c017720]   o0:0 ->i4:0 s16 / 44100 Hz / 2 channels
> [AVFilterGraph @ 0x7f929c017720] 1: abuffersink "ffplay_abuffersink"
> [AVFilterGraph @ 0x7f929c017720]   i1:0 <-o3:0 { same as o3:0 } /  { 44100 } / { all layouts and counts }
> [AVFilterGraph @ 0x7f929c017720] 2: volume "Parsed_volume_0"
> [AVFilterGraph @ 0x7f929c017720]   i2:0 <-o4:0 { same as o4:0 } / { same as i3:0 } / { all layouts }
> [AVFilterGraph @ 0x7f929c017720]   o2:0 ->i3:0 { same as o4:0 } / { same as i3:0 } / { same as i2:0 }
> [AVFilterGraph @ 0x7f929c017720] 3: aresample "auto-inserted resampler 0"
> [AVFilterGraph @ 0x7f929c017720]   i3:0 <-o2:0 { same as o4:0 } /  { 44100 } / { same as i2:0 }
> [AVFilterGraph @ 0x7f929c017720]   o3:0 ->i1:0  { s16 } / { same as i1:0 } / { same as i1:0 }
> [AVFilterGraph @ 0x7f929c017720] 4: aresample "auto-inserted resampler 1"
> [AVFilterGraph @ 0x7f929c017720]   i4:0 <-o0:0 s16 / 44100 Hz / 2 channels
> [AVFilterGraph @ 0x7f929c017720]   o4:0 ->i2:0  { flt | fltp } / { same as i3:0 } / { same as i2:0 }
> Failed to open file 'test.wav' or configure filtergraph
> [AVIOContext @ 0x7f929c005620] Statistics: 917504 bytes read, 0 seeks
> 
> Do you manage to understand what's going on here? The input file has
> unspecified channel layout.

That is exactly the kind of problems this patch aims to help understanding.
The error message tells you the problem is at "auto-inserted resampler 1"
and is about the channel layout. You can see the input channel layout has
been selected as "2 channels" while the output is still open as { same as
i2:0 }, which is { all layouts } because of volume: volume requires a
specified layout.

Regards,

-- 
  Nicolas George
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