Merge pull request #248 from wader/avc_pps-correct-more-rbsp-data

avc_pps: Correct check if there is more rbsp data
wader · May 4, 2022 · 6013588 · 6013588
2 parents d1ca8ff + b0096bc
commit 6013588
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Showing 3 changed files with 22 additions and 5 deletions.
diff --git a/format/mpeg/avc_pps.go b/format/mpeg/avc_pps.go
@@ -15,12 +15,9 @@ func init() {
 	})
 }
 
-// TODO:
-// ffmpeg does: get_bits_left(gb) > 0 && show_bits(gb, 8) != 0x80
-// we do: there is more than trailing rbsp left
 func moreRBSPData(d *decode.D) bool {
 	l := d.BitsLeft()
-	return l > 8 //|| (l == 8 && d.PeekBits(8) != 1)
+	return l >= 8 && d.PeekBits(8) != 0b1000_0000
 }
 
 func avcPPSDecode(d *decode.D, in interface{}) interface{} {
@@ -77,7 +74,6 @@ func avcPPSDecode(d *decode.D, in interface{}) interface{} {
 	d.FieldBool("constrained_intra_pred_flag")
 	d.FieldBool("redundant_pic_cnt_present_flag")
 
-	// TODO: more_data() is there non-zero bits left?
 	if moreRBSPData(d) {
 		d.FieldBool("transform_8x8_mode_flag")
 		picScalingMatrixPresentFlag := d.FieldBool("pic_scaling_matrix_present_flag")
@@ -89,6 +85,8 @@ func avcPPSDecode(d *decode.D, in interface{}) interface{} {
 			})
 		}
 		d.FieldSFn("second_chroma_qp_index_offset", sEV)
+	} else {
+		d.FieldBool("rbsp_stop_one_bit")
 	}
 
 	d.FieldRawLen("rbsp_trailing_bits", d.BitsLeft())

diff --git a/format/mpeg/testdata/avc_pps_stop_more_8bit b/format/mpeg/testdata/avc_pps_stop_more_8bit
diff --git a/format/mpeg/testdata/avc_pps_stop_more_8bit.fqtest b/format/mpeg/testdata/avc_pps_stop_more_8bit.fqtest
@@ -0,0 +1,19 @@
+$ fq -d avc_pps ddv avc_pps_stop_more_8bit
+   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|.{}: avc_pps_stop_more_8bit (avc_pps) 0x0-0x3.7 (4)
+0x0|ce                                             |.               |  pic_parameter_set_id: 0 0x0-0x0 (0.1)
+0x0|ce                                             |.               |  seq_parameter_set_id: 0 0x0.1-0x0.1 (0.1)
+0x0|ce                                             |.               |  entropy_coding_mode_flag: false 0x0.2-0x0.2 (0.1)
+0x0|ce                                             |.               |  bottom_field_pic_order_in_frame_present_flag: false 0x0.3-0x0.3 (0.1)
+0x0|ce                                             |.               |  num_slice_groups: 1 0x0.4-0x0.4 (0.1)
+0x0|ce                                             |.               |  num_ref_idx_l0_default_active: 1 0x0.5-0x0.5 (0.1)
+0x0|ce                                             |.               |  num_ref_idx_l1_default_active: 1 0x0.6-0x0.6 (0.1)
+0x0|ce                                             |.               |  weighted_pred_flag: false 0x0.7-0x0.7 (0.1)
+0x0|   1f                                          | .              |  weighted_bipred_idc: 0 0x1-0x1.1 (0.2)
+0x0|   1f                                          | .              |  pic_init_qp: 25 0x1.2-0x1.4 (0.3)
+0x0|   1f                                          | .              |  pic_init_qs: 26 0x1.5-0x1.5 (0.1)
+0x0|   1f                                          | .              |  chroma_qp_index_offset: 0 0x1.6-0x1.6 (0.1)
+0x0|   1f                                          | .              |  deblocking_filter_control_present_flag: true 0x1.7-0x1.7 (0.1)
+0x0|      20                                       |                |  constrained_intra_pred_flag: false 0x2-0x2 (0.1)
+0x0|      20                                       |                |  redundant_pic_cnt_present_flag: false 0x2.1-0x2.1 (0.1)
+0x0|      20                                       |                |  rbsp_stop_one_bit: true 0x2.2-0x2.2 (0.1)
+0x0|      20 00|                                   |   .|           |  rbsp_trailing_bits: raw bits 0x2.3-0x3.7 (1.5)