[FFmpeg-devel] [PATCH] spdifenc: IEC 61937 encapsulation of DTS-HD for HDMI

[Reimar Döffinger]

On Sat, Jan 29, 2011 at 03:36:30AM +0200, Anssi Hannula wrote:
> +/*
> + * DTS type IV (DTS-HD) can be transmitted with various frame repetition
> + * periods; longer repetition periods allow for longer packets and therefore
> + * higher bitrate. Longer repetition periods mean that the constant bitrate of
> + * the outputted IEC 61937 stream is higher.
> + * The repetition period is measured in IEC 60958 frames (4 bytes).
> + */
> +enum {
> +    DTS4_REP_PER_512   = 0x0,
> +    DTS4_REP_PER_1024  = 0x1,
> +    DTS4_REP_PER_2048  = 0x2,
> +    DTS4_REP_PER_4096  = 0x3,
> +    DTS4_REP_PER_8192  = 0x4,
> +    DTS4_REP_PER_16384 = 0x5,
> +};
> +
> +static int spdif_dts4_subtype(int period)
> +{
> +    switch (period) {
> +    case 512:   return DTS4_REP_PER_512;
> +    case 1024:  return DTS4_REP_PER_1024;
> +    case 2048:  return DTS4_REP_PER_2048;
> +    case 4096:  return DTS4_REP_PER_4096;
> +    case 8192:  return DTS4_REP_PER_8192;
> +    case 16384: return DTS4_REP_PER_16384;
> +    }
> +    return -1;
> +}

That does seem a bit extreme code-amount wise for what it does
(not ment as a serious objection).

> +        if (ctx->dtshd_fallback > 0)
> +            ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
> +        else
> +            /* skip permanently (-1) or just once (0) */
> +            ctx->dtshd_skip = 1;

Uh, and what does the value 1 which is actually used at that point mean?

> +    ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size,
> +                                  ctx->out_bytes);
> +    if (!ctx->hd_buf)
> +        return AVERROR(ENOMEM);

Huh? Do you really need to preserve the previous contents?
Otherwise av_fast_malloc could be faster and comes without that
memleak on fail.