[FFmpeg-devel] [PATCH] add E-AC-3 support to AC-3 decoder

[Michael Niedermayer]

On Sat, Jun 07, 2008 at 10:30:31AM -0400, Justin Ruggles wrote:
> Hi,
> 
> Here is a patch set to incrementally add support for E-AC-3 to the AC-3
> decoder.  There are 32 total patches.  I'm just attaching them all in
> this email instead of doing the git-send-email thing.
> 
> Commit log messages:
[...]

> [PATCH 13/32] use macro constants for array sizes in decode context

ok


> [PATCH 15/32] cosmetics: add references to spec variable names

comments below


> [PATCH 16/32] store cpl_in_use for all blocks in decode context

comments below


> [PATCH 17/32] store exp_strategy for all blocks in decode context

ok


> [PATCH 18/32] split up header parsing function

ok

rest not reviewed

[...]

> diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h
> index fc73cf7..95e6512 100644
> --- a/libavcodec/ac3dec.h
> +++ b/libavcodec/ac3dec.h
> @@ -63,14 +63,14 @@ typedef struct {
>  ///@}
>  
>  ///@defgroup cpl standard coupling
> -    int cpl_in_use;                         ///< coupling in use
> -    int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling
> -    int phase_flags_in_use;                 ///< phase flags in use
> -    int phase_flags[18];                    ///< phase flags
> -    int num_cpl_subbands;                   ///< number of coupling sub bands
> -    int num_cpl_bands;                      ///< number of coupling bands
> -    int cpl_band_struct[18];                ///< coupling band structure
> -    int cpl_coords[AC3_MAX_CHANNELS][18];   ///< coupling coordinates
> +    int cpl_in_use;                         ///< coupling in use (cplinu)
> +    int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling (chincpl)
> +    int phase_flags_in_use;                 ///< phase flags in use (phsflginu)
> +    int phase_flags[18];                    ///< phase flags (phsflg)
> +    int num_cpl_subbands;                   ///< number of coupling sub bands (ncplsubnd)
> +    int num_cpl_bands;                      ///< number of coupling bands (ncplbnd)
> +    int cpl_band_struct[18];                ///< coupling band structure (cplbndstrc)
> +    int cpl_coords[AC3_MAX_CHANNELS][18];   ///< coupling coordinates (cplco)

I think it would be clearer if the (names) where vertically aligned


[...]

> @@ -746,8 +747,8 @@ static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
>      /* coupling strategy */
>      if (get_bits1(gbc)) {
>          memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
> -        s->cpl_in_use = get_bits1(gbc);
> -        if (s->cpl_in_use) {
> +        s->cpl_in_use[blk] = get_bits1(gbc);
> +        if (s->cpl_in_use[blk]) {
>              /* coupling in use */
>              int cpl_begin_freq, cpl_end_freq;
>  
> @@ -789,10 +790,13 @@ static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
>      } else if (!blk) {
>          av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must be present in block 0\n");
>          return -1;
> +    } else {
> +        s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
>      }
> +    cpl_in_use = s->cpl_in_use[blk];

following looks simpler:

            cpl_in_use= get_bits1(gbc);
            if(cpl_in_use){
            ...
        } else {
            cpl_in_use = s->cpl_in_use[blk-1];
        }
    s->cpl_in_use[blk] = cpl_in_use;


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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