[Ffmpeg-devel] fix ac3 parser with realaudio

[Michael Niedermayer]

Hi

On Thu, Feb 08, 2007 at 06:50:22PM -0500, Justin Ruggles wrote:
> Hi,
> 
> It seems that when the AC-3 parser was modified to add E-AC-3 support,
> it stopped working with RealAudio/DolbyNet.  Below is a patch to fix it.
[...]
> @@ -667,7 +667,7 @@
>          return 0;
>  
>      bsid = show_bits_long(&bits, 29) & 0x1f;
> -    if(bsid <= 8) {             /* Normal AC-3 */
> +    if(bsid <= 10) {             /* Normal AC-3 */
>          skip_bits(&bits, 16);       /* crc */
>          fscod = get_bits(&bits, 2);
>          frmsizecod = get_bits(&bits, 6);
> @@ -686,13 +686,14 @@
>              skip_bits(&bits, 2);    /* dsurmod */
>          lfeon = get_bits1(&bits);
>  
> -        *sample_rate = ac3_sample_rates[fscod];
> -        *bit_rate = ac3_bitrates[frmsizecod] * 1000;
> +        halfratecod = bsid - 8;
> +        *sample_rate = ac3_sample_rates[fscod] >> halfratecod;
> +        *bit_rate = (ac3_bitrates[frmsizecod] * 1000) >> halfratecod;

this doesnt look correct, what is with bsid<8 ?


>          *channels = ac3_channels[acmod] + lfeon;
>          *samples = 6 * 256;
>  
>          return ac3_frame_sizes[frmsizecod][fscod] * 2;
> -    } else if (bsid >= 10 && bsid <= 16) { /* Enhanced AC-3 */
> +    } else if (bsid > 10 && bsid <= 16) { /* Enhanced AC-3 */

is this correct for E-AC3?

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

Republics decline into democracies and democracies degenerate into
despotisms. -- Aristotle
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