On 14/07/14 00:58, Mike Slinn wrote:
> Under Ubuntu 13.10 I have this version:
> $ avconv -version
> avconv version 9.13-6:9.13-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the
> Libav developers
>   built on May  9 2014 13:34:03 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
> avconv 9.13-6:9.13-0ubuntu0.14.04.1
> libavutil     52.  3. 0 / 52.  3. 0
> libavcodec    54. 35. 0 / 54. 35. 0
> libavformat   54. 20. 4 / 54. 20. 4
> libavdevice   53.  2. 0 / 53.  2. 0
> libavfilter    3.  3. 0 /  3.  3. 0
> libavresample  1.  0. 1 /  1.  0. 1
> libswscale     2.  1. 1 /  2.  1. 1
> 
> This copies all video and all 8 audio channels fine:
> $ avconv -y -i convertingSbtToEclipse.mov -c:v copy -c:a copy
> convertingSbtToEclipseMono.mov
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'convertingSbtToEclipse.mov':
>   Metadata:
>     major_brand     : qt
>     minor_version   : 0
>     compatible_brands: qt
>     creation_time   : 2014-07-13 20:26:58
>   Duration: 00:07:33.48, start: 0.000000, bitrate: 3353 kb/s
>     Stream #0.0(und): Video: h264 (Main), yuv420p, 1920x1080, 3106 kb/s,
> PAR 1:1 DAR 16:9, 34.04 fps, 6k tbn, 50 tbc
>     Metadata:
>       creation_time   : 2014-07-13 20:26:58
>     Stream #0.1(und): Audio: aac, 44100 Hz, 7.1(wide), fltp, 240 kb/s
>     Metadata:
>       creation_time   : 2014-07-13 20:26:58
> Output #0, mov, to 'convertingSbtToEclipseMono.mov':
>   Metadata:
>     major_brand     : qt
>     minor_version   : 0
>     compatible_brands: qt
>     creation_time   : 2014-07-13 20:26:58
>     encoder         : Lavf54.20.4
>     Stream #0.0(und): Video: libx264, yuv420p, 1920x1080 [PAR 1:1 DAR
> 16:9], q=2-31, 3106 kb/s, 6k tbn, 6k tbc
>     Metadata:
>       creation_time   : 2014-07-13 20:26:58
>     Stream #0.1(und): Audio: aac, 44100 Hz, 7.1(wide), 240 kb/s
>     Metadata:
>       creation_time   : 2014-07-13 20:26:58
> Stream mapping:
>   Stream #0:0 -> #0:0 (copy)
>   Stream #0:1 -> #0:1 (copy)
> Press ctrl-c to stop encoding
> frame=15437 fps=1671 q=-1.0 Lsize=  185767kB time=453.20
> bitrate=3357.9kbits/s
> video:171952kB audio:13327kB global headers:0kB muxing overhead 0.262933%
> 
> But I only want the first audio channel. The following still gives me
> all 8 audio channels:
> $ avconv -y -i convertingSbtToEclipse.mov -c:v copy -c:a copy -map 0:1
> convertingSbtToEclipseMono.mov
> 
> What is the magic incantation?

You need to use the
[channelmap](https://www.libav.org/avconv.html#channelmap) filter.

map works only on streams, and you have 2 streams here, one with 8 channels.

lu

_______________________________________________
libav-tools mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-tools

Reply via email to