[FFmpeg-devel] [GSoC][PATCH v2 2/2] mlpenc: Working MLP/TrueHD encoder

[Michael Niedermayer]

On Tue, Aug 30, 2016 at 03:53:02PM +0530, Jai Luthra wrote:
> * Multichannel support for TrueHD is experimental
> 
>     There should be downmix substreams present for 2+ channel bitstreams,
>     but ffmpeg decoder doesn't need it. Will add support for this soon.
> 
> * There might be lossless check failures on LFE channels
> 
> * 32-bit sample support has been removed for now, will add it later
> 
>     While testing, some samples gave lossless check failures when enforcing
>     s32. Probably this will also get solved with the LFE issues.
> 
> Signed-off-by: Jai Luthra <me at jailuthra.in>
> ---
> 
> > a fate test could also be added
> 
> sure. i will add it in a separate patch later.
> 
>  libavcodec/Makefile    |    2 +
>  libavcodec/allcodecs.c |    4 +-
>  libavcodec/mlp.c       |   21 +
>  libavcodec/mlp.h       |   40 +
>  libavcodec/mlpenc.c    | 2416 ++++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 2481 insertions(+), 2 deletions(-)
>  create mode 100644 libavcodec/mlpenc.c

[...]

> +/** Determines the amount of bits needed to encode the samples using no
> + *  codebooks and a specified offset.
> + */
> +static void no_codebook_bits_offset(MLPEncodeContext *ctx,
> +                                    unsigned int channel, int16_t offset,
> +                                    int32_t min, int32_t max,
> +                                    BestOffset *bo)
> +{
> +    DecodingParams *dp = ctx->cur_decoding_params;
> +    int32_t unsign;
> +    int lsb_bits;
> +
> +    min -= offset;
> +    max -= offset;
> +
> +    lsb_bits = FFMAX(number_sbits(min), number_sbits(max)) - 1;
> +
> +    lsb_bits += !!lsb_bits;
> +
> +    unsign = 1 << (lsb_bits - 1);

coverity issue 1396239 says lsb_bits can be 0 here
which would result in an undefined shift
ill send you a invite to coverity so you can take a look

thx


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

If you fake or manipulate statistics in a paper in physics you will never
get a job again.
If you fake or manipulate statistics in a paper in medicin you will get
a job for life at the pharma industry.
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