SPS Range Extension Support

[frankplow]

When using bit depths higher than 10-bit, the sps_range_extension may be include in the SPS. This adds five new flags, primarily to increase the dynamic range. It is possible to use higher bit depths without the range extension, however their benefit will be reduced.

[frankplow]

Here are the range extension features used by the 12-bit VVCv2 bitstreams:

Test	extended_precision_flag	ts_residual_coding_rice_present_in_sh_flag	rrc_rice_extension_flag	persistent_rice_adaptation_enabled_flag	reverse_last_sig_coeff_enabled_flag
12b400P12_A_Sony_2	✅	✅	✅	✅	✅
12b400P12_B_Sony_2	✅	✅	✅	✅	✅
12b400P12_C_Sony_2	✅	✅	✅	✅	✅
12b400P12_D_Sony_2	✅	✅	✅	✅	✅
12b400P12_E_Sony_2	✅	✅	✅	✅	✅
12b400P16_A_Sony_2	✅	✅	✅	✅	✅
12b400P16_B_Sony_2	✅	✅	✅	✅	✅
12b400P16_C_Sony_2	✅	✅	✅	✅	✅
12b400P16_D_Sony_2	✅	✅	✅	✅	✅
12b400P16_E_Sony_2	✅	✅	✅	✅	✅
12b420P12_A_Sony_2	✅	✅	✅	✅	✅
12b420P12_B_Sony_2	✅	✅	✅	✅	✅
12b420P12_C_Sony_2	✅	✅	✅	✅	✅
12b420P12_D_Sony_2	✅	✅	✅	✅	✅
12b420P12_E_Sony_2	✅	✅	✅	✅	✅
12b420P16_A_Sony_2	✅	✅	✅	✅	✅
12b420P16_B_Sony_2	✅	✅	✅	✅	✅
12b420P16_C_Sony_2	✅	✅	✅	✅	✅
12b420P16_D_Sony_2	✅	✅	✅	✅	✅
12b420P16_E_Sony_2	✅	✅	✅	✅	✅
12b422P12_A_Sony_2	✅	✅	✅	✅	✅
12b422P12_B_Sony_2	✅	✅	✅	✅	✅
12b422P12_C_Sony_2	✅	✅	✅	✅	✅
12b422P12_D_Sony_2	✅	✅	✅	✅	✅
12b422P12_E_Sony_2	✅	✅	✅	✅	✅
12b422P16_A_Sony_2	✅	✅	✅	✅	✅
12b422P16_B_Sony_2	✅	✅	✅	✅	✅
12b422P16_C_Sony_2	✅	✅	✅	✅	✅
12b422P16_D_Sony_2	✅	✅	✅	✅	✅
12b422P16_E_Sony_2	✅	✅	✅	✅	✅
12b444Iepp_A_Sharp_2	✅	❌	❌	❌	❌
12b444Ierrc_A_Qualcomm_2	✅	✅	✅	✅	✅
12b444Ierrc_B_Qualcomm_2	✅	✅	✅	❌	✅
12b444Ietsrc_A_Kwai_2	❌	✅	❌	❌	❌
12b444Iprrc_A_Qualcomm_2	✅	✅	✅	✅	✅
12b444Irlscp_A_OPPO_2	✅	✅	✅	✅	✅
12b444Iwpp_A_OPPO_1	✅	✅	✅	✅	✅
12b444P16_A_Sony_2	✅	✅	✅	✅	✅
12b444P16_B_Sony_2	✅	✅	✅	✅	✅
12b444P16_C_Sony_2	✅	✅	✅	✅	✅
12b444P16_D_Sony_2	✅	✅	✅	✅	✅
12b444P16_E_Sony_2	✅	✅	✅	✅	✅
12b444SPepp_A_Sharp_2	✅	❌	❌	❌	❌
12b444SPerrc_A_Qualcomm_2	✅	✅	✅	✅	✅
12b444SPetsrc_A_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_B_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_C_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_D_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_E_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_F_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_G_Kwai_2	❌	✅	❌	❌	❌
12b444SPetsrc_H_Kwai_2	❌	✅	❌	❌	❌
12b444SPprrc_A_Qualcomm_2	✅	✅	✅	✅	✅
12b444SPrlscp_A_OPPO_2	✅	✅	✅	✅	✅
12b444SPwpp_A_OPPO_1	✅	✅	✅	✅	✅
12b444epp_A_Sharp_2	✅	❌	❌	❌	❌
12b444errc_A_Qualcomm_2	✅	✅	✅	✅	✅
12b444errc_B_Qualcomm_2	✅	✅	✅	❌	✅
12b444errc_C_Qualcomm_2	✅	✅	✅	✅	✅
12b444etsrc_A_Kwai_2	❌	✅	❌	❌	❌
12b444prrc_A_Qualcomm_2	✅	✅	✅	✅	✅
12b444rlscp_A_OPPO_2	✅	✅	✅	✅	✅
12b444wpp_A_OPPO_1	✅	✅	✅	✅	✅

Annoyingly, all of the bitstreams which test only a single feature are 4:4:4. This means the range extension will be easier to implement once #86 is resolved. @nuomi2021 I don't suppose you've done any investigation into this? You said here: https://github.com/ffvvc/FFmpeg/pull/84#issuecomment-1572173468 it may be related to derive_chroma_intra_pred_mod but do you have any more pointers?

[nuomi2021]

Hi Frank, Good summary.

If you apply this patch. and run "ffmpeg -i tests/conformance/failed/v2/12b444vvc1_A_Sony_2.bit -vsync 0 -y -f rawvideo ffmpeg_patch.yuv" You will find the (64,68) cu on the frame 32 (poc is 32, decoder order is 1) is correct.

The main reason is we derive lumaIntraPredModeC based on "Table 20 – Specification of IntraPredModeC" in spec. It will return INTRA_VDIAG instead INTRA_PLANAR(the correct one)

It's wonderful if you can help double-check the spec and the code. see how to return INTRA_PLANAR

thank you.

git diff
diff --git a/libavcodec/vvc/vvc_ctu.c b/libavcodec/vvc/vvc_ctu.c
index a0a47cc819..c5810f7b0e 100644
--- a/libavcodec/vvc/vvc_ctu.c
+++ b/libavcodec/vvc/vvc_ctu.c
@@ -897,6 +897,11 @@ static void derive_chroma_intra_pred_mode(VVCLocalContext *lc,
                 break;
         }
         cu->intra_pred_mode_c = pred_mode_c[intra_chroma_pred_mode][idx];
+
+        if (fc->decode_order == 1 && cu->x0 == 64 && cu->y0 == 68) {
+            cu->intra_pred_mode_c = INTRA_PLANAR;
+    }
+
     }
     if (sps->chroma_format_idc == CHROMA_FORMAT_422 && cu->intra_pred_mode_c <= INTRA_VDIAG) {

[frankplow]

Implemented in #91.