NAK
There is DSD 512 variant
On 7/1/20, Michael Niedermayer <mich...@niedermayer.cc> wrote:
> Real files do skip coding 0 bits at the end, thus this kind of check
> does not work reliable.
>
> Fixes: Ticket 8770
> Fixes: dst-256fs44-6ch-refdstencoder.dff
>
> The samplerate is specified in ISO/IEC 14496-3:2005(E) as one of 3 fixed
> values, this also can be used to limit the duration and avoid the timeout
>
> This reverts commit f6df99dba1ae64b05d08fba8160d13eb9795042f.
> ---
> libavcodec/dstdec.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/libavcodec/dstdec.c b/libavcodec/dstdec.c
> index 771887faf9..f0926d6c09 100644
> --- a/libavcodec/dstdec.c
> +++ b/libavcodec/dstdec.c
> @@ -56,7 +56,6 @@ static const int8_t probs_code_pred_coeff[3][3] = {
> typedef struct ArithCoder {
> unsigned int a;
> unsigned int c;
> - int overread;
> } ArithCoder;
>
> typedef struct Table {
> @@ -86,6 +85,12 @@ static av_cold int decode_init(AVCodecContext *avctx)
> return AVERROR_PATCHWELCOME;
> }
>
> + // the sample rate is only allowed to be 64,128,256 * 44100 by ISO/IEC
> 14496-3:2005(E)
> + // We are a bit more tolerant here, but this check is needed to bound
> the size and duration
> + if (avctx->sample_rate > 256 * 44100)
> + return AVERROR_INVALIDDATA;
> +
> +
> if (DST_SAMPLES_PER_FRAME(avctx->sample_rate) & 7) {
> return AVERROR_PATCHWELCOME;
> }
> @@ -181,7 +186,6 @@ static void ac_init(ArithCoder *ac, GetBitContext *gb)
> {
> ac->a = 4095;
> ac->c = get_bits(gb, 12);
> - ac->overread = 0;
> }
>
> static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int
> p, int *e)
> @@ -201,8 +205,6 @@ static av_always_inline void ac_get(ArithCoder *ac,
> GetBitContext *gb, int p, in
> if (ac->a < 2048) {
> int n = 11 - av_log2(ac->a);
> ac->a <<= n;
> - if (get_bits_left(gb) < n)
> - ac->overread ++;
> ac->c = (ac->c << n) | get_bits(gb, n);
> }
> }
> @@ -355,9 +357,6 @@ static int decode_frame(AVCodecContext *avctx, void
> *data,
> prob = 128;
> }
>
> - if (ac->overread > 16)
> - return AVERROR_INVALIDDATA;
> -
> ac_get(ac, gb, prob, &residual);
> v = ((predict >> 15) ^ residual) & 1;
> dsd[((i >> 3) * channels + ch) << 2] |= v << (7 - (i & 0x7 ));
> --
> 2.17.1
>
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