[FFmpeg-devel] [PATCH 5/5] mlpenc: clean up

[Paul B Mahol]

On 1/24/20, Jai Luthra <me at jailuthra.in> wrote:
> Signed-off-by: Jai Luthra <me at jailuthra.in>
> ---
>  libavcodec/mlpenc.c | 30 ++++++++++++++----------------
>  1 file changed, 14 insertions(+), 16 deletions(-)
>
> diff --git a/libavcodec/mlpenc.c b/libavcodec/mlpenc.c
> index 0e7a9b7640..40872c42fa 100644
> --- a/libavcodec/mlpenc.c
> +++ b/libavcodec/mlpenc.c
> @@ -94,8 +94,8 @@ typedef struct BestOffset {
>      int16_t max;
>  } BestOffset;
>
> -#define HUFF_OFFSET_MIN    -16384
> -#define HUFF_OFFSET_MAX     16383
> +#define HUFF_OFFSET_MIN    (-16384)
> +#define HUFF_OFFSET_MAX    ( 16383)
>
>  /** Number of possible codebooks (counting "no codebooks") */
>  #define NUM_CODEBOOKS       4
> @@ -808,7 +808,7 @@ static void write_major_sync(MLPEncodeContext *ctx,
> uint8_t *buf, int buf_size)
>  static void write_restart_header(MLPEncodeContext *ctx, PutBitContext *pb)
>  {
>      RestartHeader *rh = ctx->cur_restart_header;
> -    int32_t lossless_check = xor_32_to_8(rh->lossless_check_data);
> +    uint8_t lossless_check = xor_32_to_8(rh->lossless_check_data);
>      unsigned int start_count = put_bits_count(pb);
>      PutBitContext tmpb;
>      uint8_t checksum;
> @@ -1017,12 +1017,10 @@ static void write_block_data(MLPEncodeContext *ctx,
> PutBitContext *pb)
>          codebook_index  [ch] = cp->codebook  - 1;
>          sign_huff_offset[ch] = cp->huff_offset;
>
> -        sign_shift = lsb_bits[ch] - 1;
> +        sign_shift = lsb_bits[ch] + (cp->codebook ? 2 - cp->codebook : -1);
>
> -        if (cp->codebook > 0) {
> +        if (cp->codebook > 0)
>              sign_huff_offset[ch] -= 7 << lsb_bits[ch];
> -            sign_shift += 3 - cp->codebook;
> -        }
>
>          /* Unsign if needed. */
>          if (sign_shift >= 0)
> @@ -1032,7 +1030,6 @@ static void write_block_data(MLPEncodeContext *ctx,
> PutBitContext *pb)
>      for (i = 0; i < dp->blocksize; i++) {
>          for (ch = rh->min_channel; ch <= rh->max_channel; ch++) {
>              int32_t sample = *sample_buffer++ >> dp->quant_step_size[ch];
> -
>              sample -= sign_huff_offset[ch];
>
>              if (codebook_index[ch] >= 0) {
> @@ -1252,7 +1249,7 @@ static void input_data_internal(MLPEncodeContext *ctx,
> const uint8_t *samples,
>                  uint32_t abs_sample;
>                  int32_t sample;
>
> -                sample = is24 ? *samples_32++ >> 8 : *samples_16++ << 8;
> +                sample = is24 ? *samples_32++ >> 8 : *samples_16++ * 256U;
>
>                  /* TODO Find out if number_sbits can be used for negative
> values. */
>                  abs_sample = FFABS(sample);
> @@ -1795,7 +1792,7 @@ static void determine_bits(MLPEncodeContext *ctx)
>  #define SAMPLE_MAX(bitdepth) ((1 << (bitdepth - 1)) - 1)
>  #define SAMPLE_MIN(bitdepth) (~SAMPLE_MAX(bitdepth))
>
> -#define MSB_MASK(bits)  (-1u << bits)
> +#define MSB_MASK(bits)  (-(1u << (bits)))
>
>  /** Applies the filter to the current samples, and saves the residual back
>   *  into the samples buffer. If the filter is too bad and overflows the
> @@ -1899,8 +1896,8 @@ static void generate_2_noise_channels(MLPEncodeContext
> *ctx)
>
>      for (i = 0; i < ctx->number_of_samples; i++) {
>          uint16_t seed_shr7 = seed >> 7;
> -        *sample_buffer++ = ((int8_t)(seed >> 15)) << rh->noise_shift;
> -        *sample_buffer++ = ((int8_t) seed_shr7)   << rh->noise_shift;
> +        *sample_buffer++ = ((int8_t)(seed >> 15)) * (1 << rh->noise_shift);
> +        *sample_buffer++ = ((int8_t) seed_shr7)   * (1 << rh->noise_shift);
>
>          seed = (seed << 16) ^ seed_shr7 ^ (seed_shr7 << 5);
>
> @@ -2071,9 +2068,10 @@ static void set_best_codebook(MLPEncodeContext *ctx)
>              best_codebook = *best_path++ - ZERO_PATH;
>              cur_bo = &ctx->best_offset[index][channel][best_codebook];
>
> -            cp->huff_offset = cur_bo->offset;
> -            cp->huff_lsbs   = cur_bo->lsb_bits +
> dp->quant_step_size[channel];
> -            cp->codebook    = best_codebook;
> +            cp->huff_offset      = cur_bo->offset;
> +            cp->sign_huff_offset = -(1 << 23);

This is not cleanup, this adds new line of code without proper explanation.

> +            cp->huff_lsbs        = cur_bo->lsb_bits +
> dp->quant_step_size[channel];
> +            cp->codebook         = best_codebook;
>          }
>      }
>  }
> @@ -2275,7 +2273,7 @@ static int mlp_encode_frame(AVCodecContext *avctx,
> AVPacket *avpkt,
>      if (restart_frame) {
>          set_major_params(ctx);
>          if (ctx->min_restart_interval != ctx->max_restart_interval)
> -        process_major_frame(ctx);
> +            process_major_frame(ctx);
>      }
>
>      if (ctx->min_restart_interval == ctx->max_restart_interval)
> --
> 2.25.0
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".