[FFmpeg-devel] [PATCH] nellymoserdec: Allow using unusual input block sizes

[Michael Niedermayer]

On Mon, Jun 14, 2010 at 02:27:20PM +0300, Martin Storsj? wrote:
> Hi,
> 
> Currently, the nellymoser decoder tries to decode all blocks in a packet 
> at once (for efficiency?), instead of only decoding the first one (as many 
> other decoders do). The audio decoders that work in that way are able to 
> decode a long stream of data without any framing, as long as they're fed 
> with enough data to decode one packet.
> 
> If the amount of blocks in the packet isn't one of the ones the decoder is 
> familiar with, it simply errors out (with a message at the AV_LOG_DEBUG 
> level, btw) - even if it would have decoded just fine if it would decode 
> only one frame at a time.
> 
> The attached patch is one way of solving it, another (less efficient) way
> would be to only decode the first block of a packet per call.
> 
> // Martin
>  nellymoserdec.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 4ba350fbb466f70d56cb8d033e030408cadac936  0001-nellymoserdec-Allow-using-unusual-input-block-sizes.patch
> From ed6b4da0a8752b3ac1cd1e612522b3f2c43caaf4 Mon Sep 17 00:00:00 2001
> From: Martin Storsjo <martin at martin.st>
> Date: Mon, 14 Jun 2010 14:20:32 +0300
> Subject: [PATCH] nellymoserdec: Allow using unusual input block sizes
> 
> ---
>  libavcodec/nellymoserdec.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/libavcodec/nellymoserdec.c b/libavcodec/nellymoserdec.c
> index 82a3f07..cda8d11 100644
> --- a/libavcodec/nellymoserdec.c
> +++ b/libavcodec/nellymoserdec.c
> @@ -178,8 +178,12 @@ static int decode_tag(AVCodecContext * avctx,
>          case 512:   // 44100Hz
>              blocks = 8; break;
>          default:
> +            if (buf_size % 64) {
>              av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size);
>              return buf_size;
> +            }
> +            blocks = buf_size / 64;
> +            break;
>      }

the switch/case is unneeed

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

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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