[FFmpeg-devel] [PATCH] ffmpeg2theora 6to2channel-resample.patch

[Reimar Döffinger]

Just some quick comments

On Sun, May 01, 2011 at 07:38:27PM +0200, Michael Niedermayer wrote:
> +/*
> +*/
> +static short clip_short(int v) {
> +    if (v < -32768)
> +        v = -32768;
> +    else if (v > 32767)
> +        v = 32767;
> +    return (short) v;
> +}

Looks like a bad reimplementation of av_clip_int16,
and generally "short" shouldn't be used but that's
already in existing code...

>      for(i=0;i<n;i++) {
> -        *output1++ = *input++;
> -        *output2++ = *input++;
> +        if (channels == 2) {
> +            /* simple stereo to stereo. Input is: l, r */
> +            l = input[0];
> +            r = input[1];
> +        } else if (channels == 6) {
> +            /* 5.1 to stereo input: [fl, fr, c, lfe, rl, rr] */
> +            int fl,fr,c,rl,rr,lfe;
> +            fl = input[0];
> +            fr = input[1];
> +            c = input[2];
> +            lfe = input[3];
> +            rl = input[4];
> +            rr = input[5];
> +
> +            l = clip_short(fl + (0.5 * rl) + (0.7 * c));
> +            r = clip_short(fr + (0.5 * rr) + (0.7 * c));
> +        } else {
> +            /* channels must be 3-5, or >= 7. l, c, r, ? */
> +            l = input[0];
> +            r = input[2];
> +        }

The ifs should hardly be inside the loop.

> @@ -150,9 +190,9 @@
>  {
>      ReSampleContext *s;
>  
> -    if ( input_channels > 2)
> +	 if ((input_channels > 2) && (input_channels != 6))
>        {
> -        av_log(NULL, AV_LOG_ERROR, "Resampling with input channels greater than 2 unsupported.\n");
> +		av_log(NULL, AV_LOG_ERROR, "Resampling with input channels other than 1,2, or 6 is unsupported.\n");

Tabs.