[FFmpeg-devel] [PATCH v8 1/2] avcodec: add support for Cunning Developments' ADPCM

[Zane van Iperen]

On Thu, 16 Apr 2020 21:37:54 +0200
"Michael Niedermayer" <michael at niedermayer.cc> wrote:

> > > > @@ -1304,6 +1329,13 @@ static int
> > > > adpcm_decode_frame(AVCodecContext *avctx, void *data, samples
> > > > += avctx->channels; }
> > > >          break;
> > > > +    case AV_CODEC_ID_ADPCM_IMA_CUNNING:
> > > > +        while (bytestream2_get_bytes_left(&gb) > 0) {
> > > > +            int v = bytestream2_get_byteu(&gb);
> > > > +            *samples++ =
> > > > adpcm_ima_cunning_expand_nibble(&c->status[0], v & 0x0F);
> > > > +            *samples++ =
> > > > adpcm_ima_cunning_expand_nibble(&c->status[0], v >> 4);
> > > > +        }
> > > > +        break;  
> > >
> > > i would add an av_assert to ensure the samples array is large
> > > enough and the code seting it stays in sync. And also so the
> > > reader knows at a glance that this is ok with only a check on the
> > > input size 
> >
> > So, something like this?
> > av_assert0(frame->nb_samples == buf_size * 2);  
> 
> as the loop runs bytestream2_get_bytes_left(&gb) iterations
> the check should be between that and nb_samples i think

In that case, would it just be better to change the while() to a for()?
Same thing, but it shows the samples/nb_samples relationship.

  for (n = 0; n < nb_samples / 2; n++) {}

There's a few other decoders that use the same while() I did
originally, so it might be worth changing them too.