[FFmpeg-devel] [RFC] LOAS (aka LATM) demuxer

[Janne Grunau]

On Mon, Aug 02, 2010 at 08:45:42PM +0300, Martin Storsj? wrote:
> On Sun, 1 Aug 2010, Janne Grunau wrote:
> 
> > +static int loas_read_audio_sync_stream(AVFormatContext *s,
> > +                                       struct latm_demux_context *latmctx)
> > +{
> > +    ByteIOContext *pb = s->pb;
> > +    int muxlength;
> > +    uint8_t *buf = latmctx->buf + latmctx->pos;
> > +    int size     = latmctx->len - latmctx->pos;
> > +
> > +    while (size >= 3) {
> > +
> > +        if ((buf[0] << 3 | buf[1] >> 5) == LOAS_SYNC_WORD) {
> > +
> > +            muxlength = ((buf[1] & 0x1f) << 8) | buf[2];
> > +            if (muxlength+3 > size) {
> > +                memmove(latmctx->buf, buf, size);
> > +                buf          = latmctx->buf;
> > +                latmctx->pos = 0;
> > +                latmctx->len = size + get_buffer(pb, latmctx->buf+size,
> > +                                                 LATM_MAX_FRAME_SIZE-size);
> > +            } else {
> > +                //av_log(s, AV_LOG_INFO, "LOAS frame of %d bytes\n", muxlength);
> > +                return muxlength+3;
> > +            }
> > +        } else
> > +            latmctx->pos++;
> > +
> > +        size = latmctx->len - latmctx->pos;
> 
> Wouldn't you want to reinitialize buf to latmctx->buf + latmctx->pos
> here, too? Otherwise, the else branch don't really have much effect.

yes, good catch. fixed and I think I should try to make it less
confusing by using only local vars and setting the buffer state
in the context before returning.

thanks

Janne