[opus] Antw: [opus-tools] [PATCH] Add channel-mapping argument to force channel mapping

[Ulrich Windl]

Hi!

I haven't looked into the code yet, but the patch uses different coding conventions like "if(" and "if ("; like wise "){" and ") {". My personal taste is to have spaces after keywords, but that's just me.

I'd prefer a consistent coding style.

Regards,
Ulrich

>>> Michael Graczyk <mgraczyk at google.com> schrieb am 26.04.2016 um 06:31 in
Nachricht
<CABcu6-gnkPHY0d8rqDie8z5OZ+WH6eb0P+k6bPit2H8i5RrS1w at mail.gmail.com>:
> This patch adds a new option "channel-mapping" to opusenc which sets
> the channel mapping family used by the multistream encoder. Please let
> me know whether adding this option is worthwhile and whether the help
> string is okay. I tried to keep it short but accurate.
> 
> The error message for an unimplemented channel mapping is "Error
> cannot create encoder: request not implemented". I do not think that
> is descriptive enough, but I also do not know of a way to determine
> which channel mapping families are supported by the multistream
> encoder. If we hard-code valid channel mappings {0, 1, 255}, opusenc
> will need to be updated when channel mappings are added to Opus.
> 
> With this patch, you can encode four streams independently with
> $ opusenc --channel-mapping 255 in.wav out.opus
> 
> When channel mapping families are added to Opus in the future
> (ambisonics, for example), this option will make it possible to use
> them.
> 
> ---
>  src/opusenc.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/src/opusenc.c b/src/opusenc.c
> index 0f83194..f2c7c48 100644
> --- a/src/opusenc.c
> +++ b/src/opusenc.c
> @@ -137,6 +137,8 @@ void usage(void)
>    printf(" --framesize n      Maximum frame size in milliseconds\n");
>    printf("                      (2.5, 5, 10, 20, 40, 60, default: 20)\n");
>    printf(" --expect-loss      Percentage packet loss to expect
> (default: 0)\n");
> +  printf(" --channel-mapping  Channel Mapping Family\n");
> +  printf("                      (default: {0, 1, 255} for {1-2, 3-8,
> 9+} channels)\n");
>    printf(" --downmix-mono     Downmix to mono\n");
>    printf(" --downmix-stereo   Downmix to stereo (if >2 channels)\n");
>    printf(" --max-delay n      Maximum container delay in milliseconds\n");
> @@ -260,6 +262,7 @@ int main(int argc, char **argv)
>      {"complexity", required_argument, NULL, 0},
>      {"framesize", required_argument, NULL, 0},
>      {"expect-loss", required_argument, NULL, 0},
> +    {"channel-mapping", required_argument, NULL, 0},
>      {"downmix-mono",no_argument,NULL, 0},
>      {"downmix-stereo",no_argument,NULL, 0},
>      {"no-downmix",no_argument,NULL, 0},
> @@ -337,6 +340,7 @@ int main(int argc, char **argv)
>    opus_int32         coding_rate=48000;
>    opus_int32         frame_size=960;
>    int                chan=2;
> +  int                channel_mapping=-1;
>    int                with_hard_cbr=0;
>    int                with_cvbr=0;
>    int                expect_loss=0;
> @@ -465,6 +469,12 @@ int main(int argc, char **argv)
>              fprintf(stderr,"Expected loss is a percent and must be 
> 0-100.\n");
>              exit(1);
>            }
> +        }else 
> if(strcmp(long_options[option_index].name,"channel-mapping")==0){
> +          channel_mapping=atoi(optarg);
> +          if(channel_mapping < 0 || channel_mapping > 255){
> +            fprintf(stderr,"Invalid channel-mapping: %s\n",optarg);
> +            exit(1);
> +          }
>          }else if(strcmp(long_options[option_index].name,"comp")==0 ||
>                   strcmp(long_options[option_index].name,"complexity")==0){
>            complexity=atoi(optarg);
> @@ -692,7 +702,11 @@ int main(int argc, char **argv)
> 
>    /*OggOpus headers*/ /*FIXME: broke forcemono*/
>    header.channels=chan;
> -  header.channel_mapping=header.channels>8?255:chan>2;
> +  if (channel_mapping >= 0) {
> +     header.channel_mapping = channel_mapping;
> +  } else {
> +     header.channel_mapping = header.channels > 8 ? 255 : header.channels > 
> 2;
> +  }
>    header.input_sample_rate=rate;
>    header.gain=inopt.gain;
> 
> -- 
> 
> Thanks,
> Michael Graczyk
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