[vlc-devel] Plugin downmix-to-stereo

[Jean-Baptiste Kempf]

On Mon, Feb 27, 2012 at 09:43:59PM +0100, Jean-Baptiste Kempf wrote :
> +#include <vlc_block.h>

Unnecessary include.

> +#define DOWNMIX_MAX_OUTPUT_CHANNELS  6

Why not 8, btw?

> +/* define channel matrix for 5.0 surround audio */
> +#define DOWNMIX_FORMAT_5_0  ( AOUT_CHAN_LEFT | AOUT_CHAN_CENTER | AOUT_CHAN_RIGHT | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT )
> +
> +/* define channel matrix for 5.1 surround audio by adding an LFE channel */
> +#define DOWNMIX_FORMAT_5_1  ( DOWNMIX_FORMAT_5_0 | AOUT_CHAN_LFE )

6.1 and 7.1 are hard to do?

> +vlc_module_begin()
> +set_shortname(N_("Downmix to stereo"))
> +set_description(N_("Downmix from 5.x channels to stereo"))
> +set_help(N_("This channel mixer provides downward mixing from the 5.1 and 5.0 (surround) channel matrices to the 2.0 (stereo) channel matrix.  It does so by applying the ITU-R BS.775-2 downward mixing matrix to the selected audio output channels and muting the remaining channels.  LFE channel information is irrelevant for downward mixing and thus discarded."))
> +set_capability("audio filter", 3)
> +set_category(CAT_AUDIO)
> +set_subcategory(SUBCAT_AUDIO_AFILTER)
> +set_callbacks(Open, Close)

Please reindent!
And same for options.

> +    /* initialise data structure */
> +    p_sys->i_output_channel_left = var_CreateGetInteger(p_filter->p_parent,
> +                                   "downmix2stereo-output-channel-left");
> +    p_sys->i_output_channel_right = var_CreateGetInteger(p_filter->p_parent,
> +                                    "downmix2stereo-output-channel-right");
> +    p_sys->b_downmix_to_mono = var_CreateGetBool(p_filter->p_parent,
> +                               "downmix2stereo-downmix-to-mono");

var_InheritInteger is not ok for you?

> +    /* check whether audio input and output formats match */
> +    if (fmt_in.i_format != fmt_out.i_format)
> +    {
> +        /* display warning message and signal failure */
> +        msg_Warn(p_filter, "audio input and output formats do not match");
> +        return -1;

Please return VLC_EGENERIC;

> +    else if (fmt_in.i_rate != fmt_out.i_rate)
> +    {
> +        /* display warning message and signal failure */
> +        msg_Warn(p_filter, "audio input and output sample rates do not match");
> +        return -1;

idem.

> +        return -1;

and again.

> +        msg_Info(p_filter, "detected compatible audio channel format");

Info? really?

> +    return 0;

Please use VLC_SUCCESS

Rest seems ok

Best regards,

-- 
Jean-Baptiste Kempf
http://www.jbkempf.com/ - +33 672 704 734
Sent from my Electronic Device