Editorial improvements for semantics (#50)

- Consistent use of specified and inferred
- Consistent use of minusX semantics
- Other small improvemnts

Co-authored-by: Andrey Norkin <40504168+andrey-norkin@users.noreply.github.com>

07.bitstream.semantics.md

@@ -115,7 +115,7 @@ should not refer to the film grain parameters associated with higher scalability
 from the previous frame in the display order and not the coding order.
 {:.alert .alert-info }
 
-**film_grain_param_set_idx** is an index of a film grain parameter set. Up to 8 separate film grain parameter
+**film_grain_param_set_idx** specifies the index of a film grain parameter set. Up to 8 separate film grain parameter
 sets may be simultaneously stored by the film grain processing module.
 
 **Note:** An encoder may use film_grain_param_set_idx to differentiate between up to 8 separate film grain models.
@@ -132,26 +132,25 @@ av1_film_grain_params_function shall be stored in the memory location denoted by
 
 **grain_seed** specifies the starting value for the pseudo-random numbers used during film grain synthesis.
 
-**update_grain_flag** equal to 1 means that a new set of parameters is sent.
-update_grain_flag equal to 0 means that the previous set of parameters in the frame display order should be used.
+**update_grain_flag** equal to 1 specifies the presence of a new set of film grain parameters. update_grain_flag equal to 0 
+specifies that the previous set of parameters in the frame display order should be used.
 
 It is a requirement of bitstream conformance that for every distinct value of film_grain_param_set_idx used in a coded video
 sequence, the first frame in the display order with that value of film_grain_param_set_idx that has apply_grain_flag flag equal to 1
 have update_grain_flag equal to 1.
 
 **Note:** This requirement means that film grain parameters associated with a particular film_grain_param_set_idx value can only
-be infered from previously signaled parameters in the display order with the same value of film_grain_param_set_idx
+be inferred from previously signaled parameters in the display order with the same value of film_grain_param_set_idx
 in the current coded video sequence.
 {:.alert .alert-info }
 
-**tempGrainSeed** is a temporary variable that is used to avoid losing the value of grain_seed when load_grain_params is called.
-When update_grain_flag is equal to 0, a previous set of parameters should be used for everything except grain_seed.
+**tempGrainSeed** is a temporary variable that is used to preserve the value of grain_seed when load_grain_params is called.
 
-**apply_units_resolution_log2** indicates the units used for indicating apply_horz_resolution and apply_vert_resolution.
+**apply_units_resolution_log2** specifies the units used for indicating apply_horz_resolution and apply_vert_resolution.
 
-**apply_vert_resolution** indicates the luma vertical resolution corresponding to the film grain synthesis parameters in units of 1 << apply_units_resolution_log2 luma samples.
+**apply_vert_resolution** specifies the luma vertical resolution corresponding to the film grain synthesis parameters in units of 1 << apply_units_resolution_log2 luma samples.
 
-**apply_horz_resolution** indicates the luma horizontal resolution corresponding to the film grain synthesis parameters in units of 1 << apply_units_resolution_log2 luma samples.
+**apply_horz_resolution** specifies the luma horizontal resolution corresponding to the film grain synthesis parameters in units of 1 << apply_units_resolution_log2 luma samples.
 
 **luma_only_flag** equal to 1 specifies that the film grain synthesis parameters do not include U and V color planes.  luma_only_flag
 equal to 0 specifies that the film grain synthesis parameters do include U and V color planes.
@@ -232,25 +231,26 @@ set may be predicted from scaling functions that belong to other film grain para
 It is a requirement of the specification conformance that the film grain parameters set at the
 decoded picture resolution have the predict_scaling_flag flag equal to zero.
 
-**film_grain_param_set_idx_for_prediction** specifies an index of a film grain parameter set that is used
+**film_grain_param_set_idx_for_prediction** specifies the index of a film grain parameter set that is used
 for prediction of scaling functions of the current film grain parameter set.
 
 It is a requirement of the conformance to the current specification that the values of the film grain parameter
  set with index film_grain_param_set_idx_for_prediction has been initialized with values of the scaling functions that in the current coded video sequence.
 
-**predict_y_scaling_flag** equal to 0 indicates that the luma scaling functions in the current film grain parameter set are
-not predicted from a different film grain parameter set. predict_y_scaling_flag equal to 1 indicates that the luma scaling
+**predict_y_scaling_flag** equal to 0 specifies that the luma scaling functions in the current film grain parameter set are
+not predicted from a different film grain parameter set. predict_y_scaling_flag equal to 1 specifies that the luma scaling
+
 functions in the current film grain
 parameter set are predicted from a different film grain parameter set indicated by film_grain_param_set_idx_for_prediction.
 
-**y_scaling_mult** specifies a multiplier used for predicting the luma film grain scaling function.
+**y_scaling_mult** specifies the multiplier used for predicting the luma film grain scaling function.
 
-**y_scaling_add** specifies an addition / intercept parameter used for predicting the luma film grain scaling function.
+**y_scaling_add** specifies the addition parameter used for predicting the luma film grain scaling function.
 
 **num_y_points_in_ref** specifies the number of points for the piecewise linear scaling function of the luma component
 in the film grain parameter set referenced with film_grain_param_set_idx_for_prediction.
 
-**bits_per_y_scaling_res** specifies the number of bits used for encoding of differences / residuals for point_y_scaling.
+**bits_per_y_scaling_res** specifies the number of bits used for encoding point_y_scaling_res[ i ].
 
 **point_y_scaling_res[ i ]** specifies the prediction difference of the parameters. The parameter is signaled using
  bits_per_y_scaling_res bits and is in the [-2 bits_per_y_value_res-1,  2bits_per_y_value_res-1-1] range.
@@ -283,9 +283,9 @@ scaling function of the luma component.
 It is a requirement of bitstream conformance that num_y_points is less than or equal to 14.
 [AMT]: # (Why need to talk about conformance? Why also restrict the value to up to 14? Same for chroma)
 
-**point_y_value_increment_bits_minus1** specifies the number of bits minus 1 that will be spent on signaling the increments of point_y_values.
+**point_y_value_increment_bits_minus1** plus 1 specifies the number of bits used for encoding point_y_values_increment[ i ].
 
-**point_y_scaling_bits_minus5** specifies the number of bits minus 5 that will be spent on signaling point_y_scaling[ i ].
+**point_y_scaling_bits_minus5** plus 5 specifies the number of bits used for encoding point_y_scaling[ i ].
 
 **point_y_value_increment[ i ]** is the increment of point_y_value [ i ] relative to the point_y_value [ i - 1 ].
 point_y_value[ i ] represents the x (luma value) coordinate for the i-th point of the piecewise linear scaling function for the luma component. The values are signaled on the scale of 0..255. (In case of 10-bit video, these values correspond to luma values divided by 4. In case of 12-bit video, these values correspond to luma values divided by 16.)
@@ -311,22 +311,22 @@ linear scaling function for luma component.
 **chroma_scaling_from_luma_flag** equal to 1 specifies that the chroma scaling is inferred from the luma scaling.
 chroma_scaling_from_luma_flag equal to 0 specifies that the chroma scaling is signaled independently.
 
-**predict_cb_scaling_flag** equal to 0 indicates that the Cb scaling functions in the current film grain parameter
-set are not predicted from a different film grain parameter set. predict_cb_scaling_flag equal to 1 indicates that
+**predict_cb_scaling_flag** equal to 0 specifies that the Cb scaling functions in the current film grain parameter
+set are not predicted from a different film grain parameter set. predict_cb_scaling_flag equal to 1 specifies that
 the Cb scaling functions in the current film grain parameter set are predicted from a film grain parameter set
  indicated by film_grain_param_set_idx_for_prediction.
 
 If predict_cb_scaling_flag is equal to 1, variables cb_mult, cb_luma_mult, and cb_offset are set equal to variables
 cb_mult, cb_luma_mult, and cb_offset in the  film grain parameter set indicated by film_grain_param_set_idx_for_prediction.
 
-**cb_scaling_mult** specifies a multiplier used for predicting the Cb film grain scaling function.
+**cb_scaling_mult** specifies the multiplier used for predicting the Cb film grain scaling function.
 
-**cb_scaling_add** specifies an addition / intercept parameter used for predicting the Cb film grain scaling function.
+**cb_scaling_add** specifies the addition parameter used for predicting the Cb film grain scaling function.
 
 **num_cb_points_in_ref** specifies the number of points for the piecewise linear scaling function of the luma
 component in the film grain parameter set referenced with film_grain_param_set_idx_for_prediction.
 
-**bits_per_cb_scaling_res** specifies the number of bits used for encoding of differences / residuals for point_cb_scaling.
+**bits_per_cb_scaling_res** specifies the number of bits used for encoding point_cb_scaling_res[ i ].
 
 **point_cb_scaling_res[ i ]** specifies the prediction difference of the parameters. The parameter is signaled
 using  bits_per_cb_scaling_res bits and is in the [-2 bits_per_cb_value_res-1,  2bits_per_cb_value_res-1-1] range.
@@ -364,13 +364,13 @@ It is a requirement of bitstream conformance that num_cb_points is less than or
 This means that the chroma scaling also needs to support up to 14 points.
 {:.alert .alert-info }
 
-**point_cb_value_increment_bits_minus1** specifies the number of bits minus 1 that will be spent on signaling the increments of point_cb_values.
+**point_cb_value_increment_bits_minus1** plus 1 specifies the number of bits used to signal point_cb_values[ i ].
 
-**point_cb_scaling_bits_minus5** specifies the number of bits minus 5 that will be spent on signaling point_cb_scaling[ i ]
+**point_cb_scaling_bits_minus5** plus 5 specifies the number of bits used to signal point_cb_scaling[ i ]
 
 **cb_scaling_offset** specifies the offset applied to obtain point_cb_scaling[ i ] values.
 
-**point_cb_value_increment[ i ]** is the increment of point_cb_value [ i ] relative to the point_cb_value [ i - 1 ].
+**point_cb_value_increment[ i ]** specifies the increment of point_cb_value [ i ] relative to the point_cb_value [ i - 1 ].
 
 point_cb_value[ i ] represents the x coordinate for the i-th point of the piece-wise linear
 scaling function for cb component. The values are signaled on the scale of 0..255.
@@ -391,23 +391,22 @@ for ( i = 0; i < num_cb_points; i++ )
     point_cb_scaling[ i ] = point_cb_scaling[ i ] + cb_scaling_offset.
 ~~~~~
 
-**predict_cr_scaling_flag** equal to 0 indicates that the Cr scaling functions in the current film grain
+**predict_cr_scaling_flag** equal to 0 specifies that the Cr scaling functions in the current film grain
 parameter set are not predicted from a different film grain parameter set. predict_cr_scaling_flag equal
-to 1 indicates that the Cr scaling functions in the current film grain parameter set are predicted
+to 1 specifies that the Cr scaling functions in the current film grain parameter set are predicted
 from a film grain parameter set indicated by film_grain_param_set_idx_for_prediction.
 
 If predict_cr_scaling_flag is equal to 1, variables cr_mult, cr_luma_mult, and cr_offset are set equal
 to variables  cr_mult, cr_luma_mult, and cr_offset in the  film grain parameter set indicated by film_grain_param_set_idx_for_prediction.
 
-**cr_scaling_mult** specifies a multiplier used for predicting the Cr film grain scaling function.
+**cr_scaling_mult** specifies the multiplier used for predicting the Cr film grain scaling function.
 
-**cr_scaling_add** specifies an addition / intercept parameter used for predicting the Cr film grain scaling function.
+**cr_scaling_add** specifies the addition parameter used for predicting the Cr film grain scaling function.
 
 **num_cr_points_in_ref** specifies the number of points for the piecewise linear scaling function of
 the luma component in the film grain parameter set referenced with film_grain_param_set_idx_for_prediction.
 
-**bits_per_cr_scaling_res** specifies the number of bits used for encoding of differences / residuals
-for point_cb_scaling.
+**bits_per_cr_scaling_res** specifies the number of bits used for encoding point_cb_scaling[ i ].
 
 **point_cr_scaling_res[ i ]** specifies the prediction difference of the parameters. The parameter
 is signaled using  bits_per_cb_scaling_res bits and is in the [-2 bits_per_cr_value_res-1,  2bits_per_cr_value_res-1-1] range.
@@ -459,13 +458,13 @@ it is a requirement of bitstream conformance that num_cr_points is not equal to
 There is no restriction for 4:2:2 or 4:4:4 chroma subsampling.
 {:.alert .alert-info }
 
-**point_cr_value_increment_bits_minus1** specifies the number of bits minus 1 that will be spent on signaling the increments of point_cr_value.
+**point_cr_value_increment_bits_minus1** plus 1 specifies the number of bits that used to signal point_cr_value_increment[ i ].
 
-**point_cr_scaling_bits_minus5** specifies the number of bits minus 5 that will be spent on signaling point_cr_scaling[ i ]
+**point_cr_scaling_bits_minus5** plus 5 specifies the number of bits used to signal point_cr_scaling[ i ]
 
 **cr_scaling_offset** specifies the offset applied to obtain point_cr_scaling[ i ] values.
 
-**point_cr_value_increment[ i ]** is the increment of point_cr_value [ i ] relative to the point_cr_value [ i - 1 ].
+**point_cr_value_increment[ i ]** specifies the increment of point_cr_value [ i ] relative to the point_cr_value [ i - 1 ].
 
 point_cr_value[ i ]  represents the x coordinate for the i-th point of the piece-wise linear
 scaling function for cr component. The values are signaled on the scale of 0..255.
@@ -486,24 +485,24 @@ for ( i = 0; i < num_cr_points; i++ )
     point_cr_scaling[ i ] = point_cr_scaling[ i ] + cr_scaling_offset.
 ~~~~~
 
-**grain_scaling_minus_8** represents the shift – 8 applied to the values of the chroma
+**grain_scaling_minus_8** plus 8 specifies the shift applied to the values of the chroma
 component. The grain_scaling_minus_8 can take values of 0..3 and determines the
 range and quantization step of the standard deviation of film grain.
 
 **ar_coeff_lag** specifies the number of auto-regressive coefficients for
 luma and chroma.
 
-**bits_per_ar_coeff_y_minus5** specifies the number of bits minus 5 that will be spent on signaling ar_coeffs_y.
+**bits_per_ar_coeff_y_minus5** plus 5 specifies the number of bits used to signal ar_coeffs_y[ i ].
 
-**ar_coeffs_y[ i ]** specifies auto-regressive coefficients used for the Y plane.
+**ar_coeffs_y[ i ]** specifies the auto-regressive coefficients used for the Y plane.
 
 The values of AR coefficients for the Y component are derived as follows
 ~~~~~ c
 for ( i = 0; i < numPosLuma; i++ )
     ar_coeffs_y[ i ] = ar_coeffs_y[ i ] - (1<<(BitsArY - 1)).
 ~~~~~
 
-**bits_per_ar_coeff_cb_minus5** specifies the number of bits minus 5 that will be spent on signaling ar_coeffs_cb.
+**bits_per_ar_coeff_cb_minus5** plus 5 specifies the number of bits used to ar_coeffs_cb[ i ].
 
 **ar_coeffs_cb[ i ]** specifies auto-regressive coefficients used for the Cb plane.
 
@@ -513,9 +512,9 @@ for ( i = 0; i < numPosChroma; i++ )
     ar_coeffs_cb[ i ] = ar_coeffs_cb[ i ] - (1<<(BitsArCb - 1)).
 ~~~~~
 
-**bits_per_ar_coeff_cr_minus5** specifies the number of bits minus 5 that will be spent on signaling ar_coeffs_cr.
+**bits_per_ar_coeff_cr_minus5** plus 5 specifies the number of bits used to singal ar_coeffs_cr[ i ].
 
-**ar_coeffs_cr[ i ]** specifies auto-regressive coefficients used for the Cr plane.
+**ar_coeffs_cr[ i ]** specifies the auto-regressive coefficients used for the Cr plane.
 
 The values of AR coefficients for the Cr component are derived as follows
 ~~~~~ c
@@ -530,31 +529,31 @@ respectively.
 **grain_scale_shift** specifies how much the Gaussian random numbers should be scaled down during
 the grain synthesis process.
 
-**cb_mult** represents a multiplier for the cb component used in the derivation of the input
+**cb_mult** specifies the multiplier for the cb component used in the derivation of the input
 index to the cb component scaling function.
 
-**cb_luma_mult** represents a multiplier for the average luma component used in the
+**cb_luma_mult** specifies the multiplier for the average luma component used in the
 derivation of the input index to the cb component scaling function.
 
-**cb_offset** represents an offset used in the derivation of the input index to the cb component
+**cb_offset** specifies the offset used in the derivation of the input index to the cb component
 scaling function.
 
-**cr_mult** represents a multiplier for the cr component used in the derivation of the input index
+**cr_mult** specifies the multiplier for the cr component used in the derivation of the input index
 to the cr component scaling function.
 
-**cr_luma_mult** represents a multiplier for the average luma component used in the
+**cr_luma_mult** specifies the multiplier for the average luma component used in the
 derivation of the input index to the cr component scaling function.
 
-**cr_offset** represents an offset used in the derivation of the input index to the cr component
+**cr_offset** specifies the offset used in the derivation of the input index to the cr component
 scaling function.
 
-**overlap_flag** equal to 1 indicates that the overlap between film grain blocks shall be
-applied. overlap_flag equal to 0 indicates that the overlap between film grain blocks shall
+**overlap_flag** equal to 1 specifies that the overlap between film grain blocks shall be
+applied. overlap_flag equal to 0 specifies that the overlap between film grain blocks shall
 not be applied.
 
-**clip_to_restricted_range_flag** equal to 1 indicates that clipping to the restricted (studio)
+**clip_to_restricted_range_flag** equal to 1 specifies that clipping to the restricted (studio)
 range is applied to the sample values after adding the film grain (see the semantics for color_range for an explanation of studio swing).
-clip_to_restricted_range_flag equal to 0 indicates that clipping to the full range shall be
+clip_to_restricted_range_flag equal to 0 specifies that clipping to the full range shall be
 applied to the sample values after adding the film grain.
 
 ### Padding bits semantics