[FFmpeg-devel] [PATCH] ac3enc: check snr_offset of 0 before failing in cbr_bit_allocation().

[Måns Rullgård]

Justin Ruggles <justin.ruggles at gmail.com> writes:

> snr_offset does not always start at a multiple of 64, so some values below 64
> could go untested without this change.
> ---
> New patch which uses 0 directly, then sets snr_offset only on success.
>
>  libavcodec/ac3enc.c |    7 +++++--
>  1 files changed, 5 insertions(+), 2 deletions(-)
>
>
> diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
> index 676bb5e..2cebb81 100644
> --- a/libavcodec/ac3enc.c
> +++ b/libavcodec/ac3enc.c
> @@ -959,8 +959,11 @@ static int cbr_bit_allocation(AC3EncodeContext *s)
>             bit_alloc(s, snr_offset) > bits_left) {
>          snr_offset -= 64;
>      }
> -    if (snr_offset < 0)
> -        return AVERROR(EINVAL);
> +    if (snr_offset < 0) {
> +        if (bit_alloc(s, 0) > bits_left)
> +            return AVERROR(EINVAL);
> +        snr_offset = 0;
> +    }
>  
>      FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
>      for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {

Looks reasonable, with the caveat that I don't actually know the details
of what this is doing.

-- 
M?ns Rullg?rd
mans at mansr.com