[FFmpeg-user] Specify FC instead of mono‏

[Kevin Wells]

> Date: Tue, 27 Oct 2015 17:42:35 +0100
> From: barsnick at gmx.net
> To: ffmpeg-user at ffmpeg.org
> Subject: Re: [FFmpeg-user] Specify FC instead of mono‏
> 
> On Tue, Oct 27, 2015 at 14:17:45 +0000, Kieran O Leary wrote:
> > Perhaps mediatrace would be worth a shot? https://mediaarea.net/mediatrace/
> 
> Ah, I didn't realize mediainfo could spit out details about the atoms.
> It can indeed...
> 
> If the samples in the mentioned ticket
> https://trac.ffmpeg.org/ticket/2865
> 
> notably SD_IVTC_8channel_ProResHQ_test.mov (from ffmpeg, incorrect)
> and     SD_IVTC_8channel_ProResHQ_test_withT3.7.8_labels.mov (from QT Player, correct)
> 
> expose exactly the same behavior, I can only say this with regards to
> the difference of the files (ignoring the developers' analysis of
> whether this can be fixed):
> 
> I believe the audio channels in question differ as such:
> The "C" center channel:
> 
> 00000D38        Channels (24 bytes)
> 00000D38         Header (8 bytes)
> 00000D38          Size:                             24 (0x00000018)
> 00000D3C          Name:                             chan
> 00000D40         Version:                           0 (0x00)
> 00000D41         Flags:                             0 (0x000000)
> 00000D44         ChannelLayoutTag:                  6553601 (0x00640001)
> 00000D48         ChannelBitmap:                     0 (0x00000000)
> 00000D4C         NumberChannelDescriptions:         0 (0x00000000)
> 
> vs.
> 
> 00000D8C        Channels (44 bytes)
> 00000D8C         Header (8 bytes)
> 00000D8C          Size:                             44 (0x0000002C)
> 00000D90          Name:                             chan
> 00000D94         Version:                           0 (0x00)
> 00000D95         Flags:                             0 (0x000000)
> 00000D98         ChannelLayoutTag:                  0 (0x00000000)
> 00000D9C         ChannelBitmap:                     0 (0x00000000)
> 00000DA0         NumberChannelDescriptions:         1 (0x00000001)
> 00000DA4         ChannelLabel:                      3 (0x00000003)
> 00000DA8         ChannelFlags:                      0 (0x00000000)
> 00000DAC         Coordinates (0):                   0.000
> 00000DB0         Coordinates (1):                   0.000
> 00000DB4         Coordinates (2):                   0.000
> 
> Similar for the two other channels: QT seems to use "ChannelLabel" (3
> here, 38 and 39 for the two others channels in the sample), which
> ffmpeg does not. (Those two are different from your samples anyway,
> ffmpeg detects them as DL and DR instead of "downmix".)
> 
> I have no idea how to fix this and won't dive into it either. ;-)
> 
> Moritz
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Thats good work finding the differences, now we just need someone kind enough who knows how to change and action this.
I can only offer testing, examples, etc..

Kind regards.