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

[Martin Storsjö]

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.

> +    }
> +
> +    return -1;
> +}


// Martin