[FFmpeg-devel] [PATCH] mpeg2: remove idct randomisation
Alexander Strange
astrange
Mon Jun 21 00:25:58 CEST 2010
On Jun 20, 2010, at 3:21 PM, Mans Rullgard wrote:
> Since the beginning of time, the MPEG2 decoder has XORed the LSB of
> all block coeffs into the last one, probably to produce a random
> dithering for masking DCT mismatch errors. This patch removes this
> randomisation. As a side-effect, the value of block_last_index is
> now correct.
Mismatch control is part of the MPEG-2 spec.
http://www.neuron2.net/library/mpeg2/iso13818-2.pdf 7.4.4
It's not done with CODEC_FLAG2_FAST (which unfortunately is copy-pasted from the normal code).
> ---
> libavcodec/mpeg12.c | 10 ---------
> tests/ref/lavf/gxf | 2 +-
> tests/ref/lavf/mxf | 4 +-
> tests/ref/lavf/ts | 2 +-
> tests/ref/seek/mpeg2reuse.mpg.ref | 40 ++++++++++++++++++------------------
> tests/ref/vsynth1/mpeg2 | 14 ++++++------
> tests/ref/vsynth1/mpeg2thread | 12 +++++-----
> tests/ref/vsynth2/mpeg2 | 12 +++++-----
> tests/ref/vsynth2/mpeg2thread | 14 ++++++------
> 9 files changed, 50 insertions(+), 60 deletions(-)
>
> diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
> index bc9ddcc..aa313ef 100644
> --- a/libavcodec/mpeg12.c
> +++ b/libavcodec/mpeg12.c
> @@ -863,9 +863,6 @@ static inline int mpeg2_decode_block_non_intra(MpegEncContext *s,
> uint8_t * const scantable= s->intra_scantable.permutated;
> const uint16_t *quant_matrix;
> const int qscale= s->qscale;
> - int mismatch;
> -
> - mismatch = 1;
>
> {
> OPEN_READER(re, &s->gb);
> @@ -882,7 +879,6 @@ static inline int mpeg2_decode_block_non_intra(MpegEncContext *s,
> if(GET_CACHE(re, &s->gb)&0x40000000)
> level= -level;
> block[0] = level;
> - mismatch ^= level;
> i++;
> SKIP_BITS(re, &s->gb, 2);
> if(((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)
> @@ -922,7 +918,6 @@ static inline int mpeg2_decode_block_non_intra(MpegEncContext *s,
> return -1;
> }
>
> - mismatch ^= level;
> block[j] = level;
> #if MIN_CACHE_BITS < 19
> UPDATE_CACHE(re, &s->gb);
> @@ -937,7 +932,6 @@ end:
> LAST_SKIP_BITS(re, &s->gb, 2);
> CLOSE_READER(re, &s->gb);
> }
> - block[63] ^= (mismatch & 1);
>
> s->block_last_index[n] = i;
> return 0;
> @@ -1024,7 +1018,6 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s,
> uint8_t * const scantable= s->intra_scantable.permutated;
> const uint16_t *quant_matrix;
> const int qscale= s->qscale;
> - int mismatch;
>
> /* DC coefficient */
> if (n < 4){
> @@ -1042,7 +1035,6 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s,
> s->last_dc[component] = dc;
> block[0] = dc << (3 - s->intra_dc_precision);
> dprintf(s->avctx, "dc=%d\n", block[0]);
> - mismatch = block[0] ^ 1;
> i = 0;
> if (s->intra_vlc_format)
> rl = &ff_rl_mpeg2;
> @@ -1083,12 +1075,10 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s,
> return -1;
> }
>
> - mismatch^= level;
> block[j] = level;
> }
> CLOSE_READER(re, &s->gb);
> }
> - block[63]^= mismatch&1;
>
> s->block_last_index[n] = i;
> return 0;
> diff --git a/tests/ref/lavf/gxf b/tests/ref/lavf/gxf
> index d147bc4..4ef0564 100644
> --- a/tests/ref/lavf/gxf
> +++ b/tests/ref/lavf/gxf
> @@ -1,3 +1,3 @@
> b52bf18b403ac9a0d12048b2f66cb24c *./tests/data/lavf/lavf.gxf
> 796392 ./tests/data/lavf/lavf.gxf
> -./tests/data/lavf/lavf.gxf CRC=0xad9e86eb
> +./tests/data/lavf/lavf.gxf CRC=0x6b2487ab
> diff --git a/tests/ref/lavf/mxf b/tests/ref/lavf/mxf
> index 84d7a09..fb76e6c 100644
> --- a/tests/ref/lavf/mxf
> +++ b/tests/ref/lavf/mxf
> @@ -1,6 +1,6 @@
> 8e120da0ccd70c4475fdee13fc5f3d0b *./tests/data/lavf/lavf.mxf
> 525881 ./tests/data/lavf/lavf.mxf
> -./tests/data/lavf/lavf.mxf CRC=0xb6aa0849
> +./tests/data/lavf/lavf.mxf CRC=0xf9924ae6
> b3174e2db508564c1cce0b5e3c1bc1bd *./tests/data/lavf/lavf.mxf_d10
> 5330989 ./tests/data/lavf/lavf.mxf_d10
> -./tests/data/lavf/lavf.mxf_d10 CRC=0xc3f4f92e
> +./tests/data/lavf/lavf.mxf_d10 CRC=0x573076ae
> diff --git a/tests/ref/lavf/ts b/tests/ref/lavf/ts
> index 5b046fb..5cfb6c0 100644
> --- a/tests/ref/lavf/ts
> +++ b/tests/ref/lavf/ts
> @@ -1,3 +1,3 @@
> e0c183639709d6e75bc553a3ed1333dd *./tests/data/lavf/lavf.ts
> 406644 ./tests/data/lavf/lavf.ts
> -./tests/data/lavf/lavf.ts CRC=0x133216c1
> +./tests/data/lavf/lavf.ts CRC=0x53173ec7
> diff --git a/tests/ref/seek/mpeg2reuse.mpg.ref b/tests/ref/seek/mpeg2reuse.mpg.ref
> index c4ae3ea..2268bf0 100644
> --- a/tests/ref/seek/mpeg2reuse.mpg.ref
> +++ b/tests/ref/seek/mpeg2reuse.mpg.ref
> @@ -1,46 +1,46 @@
> -ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20829
> +ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20833
> ret: 0 st:-1 flags:0 ts:-1.000000
> -ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20829
> +ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20833
> ret: 0 st:-1 flags:1 ts: 1.894167
> -ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 337078 size: 26840
> +ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 336721 size: 26840
> ret: 0 st: 0 flags:0 ts: 0.788334
> -ret: 0 st: 0 flags:1 dts: 0.880000 pts: NOPTS pos: 141401 size: 23537
> +ret: 0 st: 0 flags:1 dts: 0.880000 pts: NOPTS pos: 141341 size: 23536
> ret:-1 st: 0 flags:1 ts:-0.317499
> ret:-1 st:-1 flags:0 ts: 2.576668
> ret: 0 st:-1 flags:1 ts: 1.470835
> -ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 232037 size: 26192
> +ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 231918 size: 26198
> ret: 0 st: 0 flags:0 ts: 0.365002
> -ret: 0 st: 0 flags:1 dts: 0.400000 pts: NOPTS pos: 63793 size: 21295
> +ret: 0 st: 0 flags:1 dts: 0.400000 pts: NOPTS pos: 63746 size: 21296
> ret:-1 st: 0 flags:1 ts:-0.740831
> ret:-1 st:-1 flags:0 ts: 2.153336
> ret: 0 st:-1 flags:1 ts: 1.047503
> -ret: 0 st: 0 flags:1 dts: 0.880000 pts: NOPTS pos: 141401 size: 23537
> +ret: 0 st: 0 flags:1 dts: 0.880000 pts: NOPTS pos: 141341 size: 23536
> ret: 0 st: 0 flags:0 ts:-0.058330
> -ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20829
> +ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20833
> ret: 0 st: 0 flags:1 ts: 2.835837
> -ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 337078 size: 26840
> +ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 336721 size: 26840
> ret: 0 st:-1 flags:0 ts: 1.730004
> -ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 337078 size: 26840
> +ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 336721 size: 26840
> ret: 0 st:-1 flags:1 ts: 0.624171
> -ret: 0 st: 0 flags:1 dts: 0.400000 pts: NOPTS pos: 63793 size: 21295
> +ret: 0 st: 0 flags:1 dts: 0.400000 pts: NOPTS pos: 63746 size: 21296
> ret: 0 st: 0 flags:0 ts:-0.481662
> -ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20829
> +ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20833
> ret: 0 st: 0 flags:1 ts: 2.412505
> -ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 337078 size: 26840
> +ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 336721 size: 26840
> ret: 0 st:-1 flags:0 ts: 1.306672
> -ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 232037 size: 26192
> +ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 231918 size: 26198
> ret: 0 st:-1 flags:1 ts: 0.200839
> -ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20829
> +ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20833
> ret: 0 st: 0 flags:0 ts:-0.904994
> -ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20829
> +ret: 0 st: 0 flags:1 dts: 0.000000 pts: NOPTS pos: 0 size: 20833
> ret: 0 st: 0 flags:1 ts: 1.989173
> -ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 337078 size: 26840
> +ret: 0 st: 0 flags:1 dts: 1.840000 pts: NOPTS pos: 336721 size: 26840
> ret: 0 st:-1 flags:0 ts: 0.883340
> -ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 232037 size: 26192
> +ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 231918 size: 26198
> ret:-1 st:-1 flags:1 ts:-0.222493
> ret:-1 st: 0 flags:0 ts: 2.671674
> ret: 0 st: 0 flags:1 ts: 1.565841
> -ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 232037 size: 26192
> +ret: 0 st: 0 flags:1 dts: 1.360000 pts: NOPTS pos: 231918 size: 26198
> ret: 0 st:-1 flags:0 ts: 0.460008
> -ret: 0 st: 0 flags:1 dts: 0.880000 pts: NOPTS pos: 141401 size: 23537
> +ret: 0 st: 0 flags:1 dts: 0.880000 pts: NOPTS pos: 141341 size: 23536
> ret:-1 st:-1 flags:1 ts:-0.645825
> diff --git a/tests/ref/vsynth1/mpeg2 b/tests/ref/vsynth1/mpeg2
> index 7269080..a06f550 100644
> --- a/tests/ref/vsynth1/mpeg2
> +++ b/tests/ref/vsynth1/mpeg2
> @@ -1,20 +1,20 @@
> fbddea2368cd2028fc8db4dfd4682e94 *./tests/data/vsynth1/mpeg2.mpg
> 728044 ./tests/data/vsynth1/mpeg2.mpg
> -b41ca49c1a02e66ce64d262e2cdaec15 *./tests/data/mpeg2.vsynth1.out.yuv
> +fcdc3f7c713c05790409f3420f11be23 *./tests/data/mpeg2.vsynth1.out.yuv
> stddev: 7.65 PSNR: 30.45 bytes: 7603200/ 7603200
> 8f6b20714918e6443e0c03716ed06f0d *./tests/data/vsynth1/mpeg2ivlc-qprd.mpg
> 783552 ./tests/data/vsynth1/mpeg2ivlc-qprd.mpg
> -98eb9da15f880978e7f2ee1e7ce476ef *./tests/data/mpeg2.vsynth1.out.yuv
> +4320470745bd32065be74f4e70cc164d *./tests/data/mpeg2.vsynth1.out.yuv
> stddev: 10.07 PSNR: 28.06 bytes: 7603200/ 7603200
> af0cb75451aaa807beb5102707a98823 *./tests/data/vsynth1/mpeg2_422.mpg
> 728200 ./tests/data/vsynth1/mpeg2_422.mpg
> -29b518282493203e83b27a939795dc3a *./tests/data/mpeg2.vsynth1.out.yuv
> +a2dc49b3a7d83f412e630f194f64e7cc *./tests/data/mpeg2.vsynth1.out.yuv
> stddev: 63.33 PSNR: 12.10 bytes: 10137600/ 7603200
> 4c067397b504d65532d7779cd36f3f88 *./tests/data/vsynth1/mpeg2.mpg
> 725668 ./tests/data/vsynth1/mpeg2.mpg
> -9f7b065f98d57cdecf90e6f7a2524eb5 *./tests/data/mpeg2.vsynth1.out.yuv
> -stddev: 7.65 PSNR: 30.45 bytes: 7603200/ 7603200
> +c2e4292876fc12e89824d05262a142d1 *./tests/data/mpeg2.vsynth1.out.yuv
> +stddev: 7.66 PSNR: 30.45 bytes: 7603200/ 7603200
> ec3f6713c88a2b41f6c369fd64341077 *./tests/data/vsynth1/mpeg2i.mpg
> 737473 ./tests/data/vsynth1/mpeg2i.mpg
> -97615390fdd69abfcbc7e02df863a7d2 *./tests/data/mpeg2.vsynth1.out.yuv
> -stddev: 7.67 PSNR: 30.43 bytes: 7603200/ 7603200
> +769b636abe26473e66385a899317c1b0 *./tests/data/mpeg2.vsynth1.out.yuv
> +stddev: 7.68 PSNR: 30.42 bytes: 7603200/ 7603200
> diff --git a/tests/ref/vsynth1/mpeg2thread b/tests/ref/vsynth1/mpeg2thread
> index c2e2c4f..c0f7a26 100644
> --- a/tests/ref/vsynth1/mpeg2thread
> +++ b/tests/ref/vsynth1/mpeg2thread
> @@ -1,12 +1,12 @@
> ecd183706688bd977c9994c3d1b23d61 *./tests/data/vsynth1/mpeg2thread.mpg
> 801313 ./tests/data/vsynth1/mpeg2thread.mpg
> -d1658911ca83f5616c1d32abc40750de *./tests/data/mpeg2thread.vsynth1.out.yuv
> +c9d33e8f71ba026a906b2176c83895ec *./tests/data/mpeg2thread.vsynth1.out.yuv
> stddev: 7.63 PSNR: 30.48 bytes: 7603200/ 7603200
> 23d600b026222253c2340e23300a4c02 *./tests/data/vsynth1/mpeg2threadivlc.mpg
> 791773 ./tests/data/vsynth1/mpeg2threadivlc.mpg
> -d1658911ca83f5616c1d32abc40750de *./tests/data/mpeg2thread.vsynth1.out.yuv
> +c9d33e8f71ba026a906b2176c83895ec *./tests/data/mpeg2thread.vsynth1.out.yuv
> stddev: 7.63 PSNR: 30.48 bytes: 7603200/ 7603200
> -d119fe917dd81d1ff758b4ce684a8d9d *./tests/data/vsynth1/mpeg2reuse.mpg
> -2074636 ./tests/data/vsynth1/mpeg2reuse.mpg
> -92ced6afe8c02304943c400cce51a5f4 *./tests/data/mpeg2thread.vsynth1.out.yuv
> -stddev: 7.66 PSNR: 30.44 bytes: 7603200/ 7603200
> +f2a0f85d5e59d34d3cf49053fe533eed *./tests/data/vsynth1/mpeg2reuse.mpg
> +2075375 ./tests/data/vsynth1/mpeg2reuse.mpg
> +3f86f91251113bc0694df11f5083b6a4 *./tests/data/mpeg2thread.vsynth1.out.yuv
> +stddev: 7.67 PSNR: 30.43 bytes: 7603200/ 7603200
> diff --git a/tests/ref/vsynth2/mpeg2 b/tests/ref/vsynth2/mpeg2
> index f4a1c96..228dc33 100644
> --- a/tests/ref/vsynth2/mpeg2
> +++ b/tests/ref/vsynth2/mpeg2
> @@ -1,20 +1,20 @@
> 2d55ce623a7be4e8136f80266e487678 *./tests/data/vsynth2/mpeg2.mpg
> 198667 ./tests/data/vsynth2/mpeg2.mpg
> -b7cae8a1f751b821cddcbe4d5dbc518c *./tests/data/mpeg2.vsynth2.out.yuv
> -stddev: 4.96 PSNR: 34.20 bytes: 7603200/ 7603200
> +b408fcfff4192c74a464c00056fc689b *./tests/data/mpeg2.vsynth2.out.yuv
> +stddev: 4.97 PSNR: 34.20 bytes: 7603200/ 7603200
> 1ba5efeb53fab7b4b71edc96d86f6c91 *./tests/data/vsynth2/mpeg2ivlc-qprd.mpg
> 244694 ./tests/data/vsynth2/mpeg2ivlc-qprd.mpg
> -b26e21599dee48a174bdbc40b2817e55 *./tests/data/mpeg2.vsynth2.out.yuv
> +642da3c9e4b05b7645033342d922fa40 *./tests/data/mpeg2.vsynth2.out.yuv
> stddev: 4.15 PSNR: 35.76 bytes: 7603200/ 7603200
> 2c8e33c2d2efab86fc16a195f6877682 *./tests/data/vsynth2/mpeg2_422.mpg
> 356124 ./tests/data/vsynth2/mpeg2_422.mpg
> -de44597c6c470f3e7019b31245a3ff69 *./tests/data/mpeg2.vsynth2.out.yuv
> +e0491e08873b71a4977a20da96c1d82c *./tests/data/mpeg2.vsynth2.out.yuv
> stddev: 54.55 PSNR: 13.39 bytes: 10137600/ 7603200
> f979bcca866e6e4cad5dc6cb06e56cfb *./tests/data/vsynth2/mpeg2.mpg
> 198041 ./tests/data/vsynth2/mpeg2.mpg
> -f6d9bf24ff8676a7f6076c05cd2c81a3 *./tests/data/mpeg2.vsynth2.out.yuv
> +74be9ceb2cd709cdc476511dc0830b10 *./tests/data/mpeg2.vsynth2.out.yuv
> stddev: 4.97 PSNR: 34.19 bytes: 7603200/ 7603200
> f90197a8b6e62ae25f82625337f27240 *./tests/data/vsynth2/mpeg2i.mpg
> 204579 ./tests/data/vsynth2/mpeg2i.mpg
> -ea5057b60146c06d40449cdfc686bf13 *./tests/data/mpeg2.vsynth2.out.yuv
> +8163a20aac64dc3013bcba713a1af090 *./tests/data/mpeg2.vsynth2.out.yuv
> stddev: 4.98 PSNR: 34.18 bytes: 7603200/ 7603200
> diff --git a/tests/ref/vsynth2/mpeg2thread b/tests/ref/vsynth2/mpeg2thread
> index 9253d7f..de32305 100644
> --- a/tests/ref/vsynth2/mpeg2thread
> +++ b/tests/ref/vsynth2/mpeg2thread
> @@ -1,12 +1,12 @@
> 889c754a42d7689b228853e1ece6d345 *./tests/data/vsynth2/mpeg2thread.mpg
> 179650 ./tests/data/vsynth2/mpeg2thread.mpg
> -8c6a7ed2eb73bd18fd2bb9829464100d *./tests/data/mpeg2thread.vsynth2.out.yuv
> -stddev: 4.72 PSNR: 34.65 bytes: 7603200/ 7603200
> +754ac00c5134be8955b0c3ea41a969c6 *./tests/data/mpeg2thread.vsynth2.out.yuv
> +stddev: 4.72 PSNR: 34.64 bytes: 7603200/ 7603200
> 10b900e32809758857c596d56746e00e *./tests/data/vsynth2/mpeg2threadivlc.mpg
> 178801 ./tests/data/vsynth2/mpeg2threadivlc.mpg
> -8c6a7ed2eb73bd18fd2bb9829464100d *./tests/data/mpeg2thread.vsynth2.out.yuv
> -stddev: 4.72 PSNR: 34.65 bytes: 7603200/ 7603200
> -864d6bf2982a61e510003a518be65a2d *./tests/data/vsynth2/mpeg2reuse.mpg
> -383419 ./tests/data/vsynth2/mpeg2reuse.mpg
> -bb20fa080cfd2b0a687ea7376ff4f902 *./tests/data/mpeg2thread.vsynth2.out.yuv
> +754ac00c5134be8955b0c3ea41a969c6 *./tests/data/mpeg2thread.vsynth2.out.yuv
> +stddev: 4.72 PSNR: 34.64 bytes: 7603200/ 7603200
> +d0f58c54fca40ba78e37ffa2a8bc1adb *./tests/data/vsynth2/mpeg2reuse.mpg
> +382932 ./tests/data/vsynth2/mpeg2reuse.mpg
> +75faa81962f651a5d7bc201a911264b7 *./tests/data/mpeg2thread.vsynth2.out.yuv
> stddev: 4.73 PSNR: 34.63 bytes: 7603200/ 7603200
> --
> 1.7.1
>
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