[FFmpeg-devel] [PATCH 1/4] h261, h263 decoders: convert to RL_VLC.

[Michael Niedermayer]

On Sun, Aug 31, 2014 at 04:48:41PM +0200, Reimar Döffinger wrote:
> Some additional optimizations in following patch.
> 
> Signed-off-by: Reimar Döffinger <Reimar.Doeffinger at gmx.de>
> ---
>  libavcodec/flv.h        |  1 -
>  libavcodec/flvdec.c     | 12 ----------
>  libavcodec/h261dec.c    | 27 ++++++++++++++---------
>  libavcodec/ituh263dec.c | 58 ++++++++++++++++++++++++++++++++++++-------------
>  4 files changed, 60 insertions(+), 38 deletions(-)
> 
> diff --git a/libavcodec/flv.h b/libavcodec/flv.h
> index 16bc88b..df50820 100644
> --- a/libavcodec/flv.h
> +++ b/libavcodec/flv.h
> @@ -28,6 +28,5 @@ void ff_flv_encode_picture_header(MpegEncContext * s, int picture_number);
>  void ff_flv2_encode_ac_esc(PutBitContext *pb, int slevel, int level, int run, int last);
>  
>  int ff_flv_decode_picture_header(MpegEncContext *s);
> -void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last);
>  
>  #endif /* AVCODEC_FLV_H */
> diff --git a/libavcodec/flvdec.c b/libavcodec/flvdec.c
> index 3b048f6..db413f2 100644
> --- a/libavcodec/flvdec.c
> +++ b/libavcodec/flvdec.c
> @@ -22,18 +22,6 @@
>  #include "flv.h"
>  #include "libavutil/imgutils.h"
>  
> -void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last)
> -{
> -    int is11 = get_bits1(gb);
> -    *last = get_bits1(gb);
> -    *run  = get_bits(gb, 6);
> -    if (is11) {
> -        *level = get_sbits(gb, 11);
> -    } else {
> -        *level = get_sbits(gb, 7);
> -    }
> -}
> -
>  int ff_flv_decode_picture_header(MpegEncContext *s)
>  {
>      int format, width, height;
> diff --git a/libavcodec/h261dec.c b/libavcodec/h261dec.c
> index 301ecc1..5f0eb59 100644
> --- a/libavcodec/h261dec.c
> +++ b/libavcodec/h261dec.c
> @@ -258,7 +258,7 @@ static int decode_mv_component(GetBitContext *gb, int v)
>  static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
>  {
>      MpegEncContext *const s = &h->s;
> -    int code, level, i, j, run;
> +    int level, i, j, run;
>      RLTable *rl = &ff_h261_rl_tcoeff;
>      const uint8_t *scan_table;
>  
> @@ -303,27 +303,32 @@ static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
>          s->block_last_index[n] = i - 1;
>          return 0;
>      }
> +    {
> +    OPEN_READER(re, &s->gb);
>      for (;;) {
> -        code = get_vlc2(&s->gb, rl->vlc.table, TCOEFF_VLC_BITS, 2);
> -        if (code < 0) {
> +        UPDATE_CACHE(re, &s->gb);
> +        GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TCOEFF_VLC_BITS, 2, 0);
> +        if (run == 66 && level) {
>              av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n",
>                     s->mb_x, s->mb_y);
>              return -1;
>          }
> -        if (code == rl->n) {
> +        if (run == 66) {

the "if (run == 66 && level) {" could be put under run == 66, if thats
faster
though maybe better as a seperate patch

patch should be ok

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

Dictatorship naturally arises out of democracy, and the most aggravated
form of tyranny and slavery out of the most extreme liberty. -- Plato
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