update bitstream-io 2.2->4.9, BitRead trait

* update the `bitstream-io` dependency. This produces a ~10% improvement
  on some of the annexb and nal benchmarks. Besides needing a few
  internal changes, this is a breaking API change because
  `crate::bitstream_io` and `crate::rbsp::{Numeric, Primitive}` were
  exposed.

* update MSRV 1.81->1.83 to match. (Arguable whether this is a breaking
  change. Many crates seem to say no. `h264-reader` doesn't have an
  explicit policy.)

* update `BitRead` to match its `read` vs `read_var` change in
  <tuffy/bitstream-io@d45beee>.
  The same rationale there applies here.

* `BitRead::read_bool` -> `BitRead::read_bit`, matching the upstream
  trait's name. The old name `read_bool` came from the `bitreader` crate
  we haven't used since 7a02a3b. I previously tried to match upstream
  in 7ffae81 but apparently missed this one.

* rename `BitReaderError::ReadErrorFor` to `BitReaderError::ReadError`.
  This variant was introduced alongside `BitReaderError::ReadError` in
  e0d5ad0. After 7ffae81, callers finished migrated from the old
  methods that didn't take a syntax element name to the new ones that
  do and the old variant was removed. The `For` suffix is just puzzling
  now, and the `ExpGolombTooLarge` variant doesn't have it.

* remove the unused and unexplained `BitReaderError::Unaligned` variant.

* update a few comments. `read` previously said it was for unsigned
  values, but it actually supported either, and one field
  (`nal::sei::pic_timing::CountingType::time_offset`) took advantage of
  this.

Author: scottlamb

CHANGELOG.md

@@ -4,8 +4,11 @@
 
 ### Changed
 
+*   BREAKING CHANGE: Updated `bitstream-io` dependency from 2.2 to 4.9 and altered `rbsp::BitRead` trait to
+    match its conventions.
 *   BREAKING CHANGE: `Profile::from_profile_idc()` now accepts `ConstraintFlags` to distinguish constrained/intra profile variants. Add `Profile` enum variants: `ConstrainedBaseline`, `ProgressiveHigh`, `ConstrainedHigh`, `High10Intra`, `High422Intra`, `High444Intra`, `ScalableConstrainedBaseline`, `ScalableConstrainedHigh`, `ScalableHighIntra`.
 *   BREAKING CHANGE: `SliceHeader::from_bits()` now takes an additional `header_extension: Option<&NalHeaderExtension>` parameter. Pass `None` for standard AVC NAL types (1/5). For MVC NAL types (20/21), pass the parsed extension to enable correct `idr_pic_flag` derivation and MVC ref pic list modification parsing.
+*   Update minimum supported Rust version from 1.81 to 1.83.
 
 ### Added
 

Cargo.toml

@@ -10,9 +10,10 @@ readme = "README.md"
 repository = "https://github.com/dholroyd/h264-reader"
 edition = "2018"
 exclude = ["/*.h264"]
+rust-version = "1.83"
 
 [dependencies]
-bitstream-io = "2.2"
+bitstream-io = "4.9"
 hex-slice = "0.1.4"
 memchr = "2.1.1"
 rfc6381-codec = "0.2"

benches/bench.rs

@@ -108,7 +108,7 @@ fn h264_reader(c: &mut Criterion) {
                     nal.header().unwrap(),
                     None,
                 ) {
-                    Err(SliceHeaderError::RbspError(BitReaderError::ReaderErrorFor(_, e))) => {
+                    Err(SliceHeaderError::RbspError(BitReaderError::ReaderError(_, e))) => {
                         assert_eq!(e.kind(), ErrorKind::WouldBlock);
                     }
                     Err(e) => panic!("{:?}", e),

rust-toolchain.toml

@@ -1,2 +1,2 @@
 [toolchain]
-channel = "1.81"
+channel = "1.83"

src/lib.rs

@@ -5,8 +5,6 @@
 
 use std::fmt::Debug;
 
-pub use bitstream_io;
-
 pub mod annexb;
 pub mod avcc;
 pub mod nal;

src/nal/aud.rs

@@ -63,7 +63,7 @@ pub struct AccessUnitDelimiter {
 
 impl AccessUnitDelimiter {
     pub fn from_bits<R: BitRead>(mut r: R) -> Result<AccessUnitDelimiter, AudError> {
-        let val: u8 = r.read(3, "primary_pic_type")?;
+        let val: u8 = r.read::<3, _>("primary_pic_type")?;
         let primary_pic_type =
             PrimaryPicType::from_id(val).map_err(AudError::InvalidPrimaryPicType)?;
         r.finish_rbsp()?;

src/nal/mod.rs

@@ -350,9 +350,9 @@ pub fn extended_rbsp_bytes<N: Nal>(nal: &N) -> rbsp::ByteReader<N::BufRead> {
 ///
 /// // Reading RBSP as a bit sequence:
 /// let mut r = nal.rbsp_bits();
-/// assert_eq!(r.read::<u8>(4, "first nibble").unwrap(), 0x1);
-/// assert_eq!(r.read::<u8>(4, "second nibble").unwrap(), 0x2);
-/// assert_eq!(r.read::<u32>(23, "23 bits at a time").unwrap(), 0x1a_00_00);
+/// assert_eq!(r.read::<4, u8>("first nibble").unwrap(), 0x1);
+/// assert_eq!(r.read::<4, u8>("second nibble").unwrap(), 0x2);
+/// assert_eq!(r.read::<23, u32>("23 bits at a time").unwrap(), 0x1a_00_00);
 /// assert!(r.has_more_rbsp_data("more left").unwrap());
 /// ```
 pub trait Nal {

src/nal/pps.rs

@@ -113,7 +113,7 @@ impl SliceGroup {
             }),
             3 | 4 | 5 => {
                 let slice_group_change_direction_flag =
-                    r.read_bool("slice_group_change_direction_flag")?;
+                    r.read_bit("slice_group_change_direction_flag")?;
                 let slice_group_change_rate_minus1 = r.read_ue("slice_group_change_rate_minus1")?;
                 if slice_group_change_rate_minus1 > sps.pic_size_in_map_units() - 1 {
                     return Err(PpsError::InvalidSliceGroupChangeRateMinus1(
@@ -180,7 +180,7 @@ impl SliceGroup {
         let size = (1f64 + f64::from(num_slice_groups_minus1)).log2().ceil() as u32;
         let mut run_length_minus1 = Vec::with_capacity(num_slice_groups_minus1 as usize + 1);
         for _ in 0..pic_size_in_map_units_minus1 + 1 {
-            run_length_minus1.push(r.read(size, "slice_group_id")?);
+            run_length_minus1.push(r.read_var(size, "slice_group_id")?);
         }
         Ok(run_length_minus1)
     }
@@ -199,7 +199,7 @@ impl PicScalingMatrix {
         sps: &sps::SeqParameterSet,
         transform_8x8_mode_flag: bool,
     ) -> Result<Option<PicScalingMatrix>, PpsError> {
-        let pic_scaling_matrix_present_flag = r.read_bool("pic_scaling_matrix_present_flag")?;
+        let pic_scaling_matrix_present_flag = r.read_bit("pic_scaling_matrix_present_flag")?;
 
         if !pic_scaling_matrix_present_flag {
             return Ok(None);
@@ -219,7 +219,7 @@ impl PicScalingMatrix {
         let mut scaling_list8x8 = Vec::with_capacity(count);
 
         for i in 0..6 + count {
-            let seq_scaling_list_present_flag = r.read_bool("seq_scaling_list_present_flag")?;
+            let seq_scaling_list_present_flag = r.read_bit("seq_scaling_list_present_flag")?;
             if i < 6 {
                 scaling_list4x4.push(
                     sps::ScalingList::<16>::read(r, seq_scaling_list_present_flag)
@@ -258,7 +258,7 @@ impl PicParameterSetExtra {
         sps: &sps::SeqParameterSet,
     ) -> Result<Option<PicParameterSetExtra>, PpsError> {
         Ok(if r.has_more_rbsp_data("transform_8x8_mode_flag")? {
-            let transform_8x8_mode_flag = r.read_bool("transform_8x8_mode_flag")?;
+            let transform_8x8_mode_flag = r.read_bit("transform_8x8_mode_flag")?;
             let extra = PicParameterSetExtra {
                 transform_8x8_mode_flag,
                 pic_scaling_matrix: PicScalingMatrix::read(r, sps, transform_8x8_mode_flag)?,
@@ -328,9 +328,9 @@ impl PicParameterSet {
         let pps = PicParameterSet {
             pic_parameter_set_id,
             seq_parameter_set_id,
-            entropy_coding_mode_flag: r.read_bool("entropy_coding_mode_flag")?,
+            entropy_coding_mode_flag: r.read_bit("entropy_coding_mode_flag")?,
             bottom_field_pic_order_in_frame_present_flag: r
-                .read_bool("bottom_field_pic_order_in_frame_present_flag")?,
+                .read_bit("bottom_field_pic_order_in_frame_present_flag")?,
             slice_groups: Self::read_slice_groups(&mut r, seq_parameter_set)?,
             num_ref_idx_l0_default_active_minus1: read_num_ref_idx(
                 &mut r,
@@ -340,15 +340,15 @@ impl PicParameterSet {
                 &mut r,
                 "num_ref_idx_l1_default_active_minus1",
             )?,
-            weighted_pred_flag: r.read_bool("weighted_pred_flag")?,
-            weighted_bipred_idc: r.read(2, "weighted_bipred_idc")?,
+            weighted_pred_flag: r.read_bit("weighted_pred_flag")?,
+            weighted_bipred_idc: r.read::<2, _>("weighted_bipred_idc")?,
             pic_init_qp_minus26: r.read_se("pic_init_qp_minus26")?,
             pic_init_qs_minus26: r.read_se("pic_init_qs_minus26")?,
             chroma_qp_index_offset: r.read_se("chroma_qp_index_offset")?,
             deblocking_filter_control_present_flag: r
-                .read_bool("deblocking_filter_control_present_flag")?,
-            constrained_intra_pred_flag: r.read_bool("constrained_intra_pred_flag")?,
-            redundant_pic_cnt_present_flag: r.read_bool("redundant_pic_cnt_present_flag")?,
+                .read_bit("deblocking_filter_control_present_flag")?,
+            constrained_intra_pred_flag: r.read_bit("constrained_intra_pred_flag")?,
+            redundant_pic_cnt_present_flag: r.read_bit("redundant_pic_cnt_present_flag")?,
             extension: PicParameterSetExtra::read(&mut r, seq_parameter_set)?,
         };
         let qp_bd_offset_y = 6 * seq_parameter_set.chroma_info.bit_depth_luma_minus8;

src/nal/prefix.rs

@@ -83,14 +83,14 @@ impl PrefixNalUnit {
             NalHeaderExtension::Svc(_) => {
                 // SVC prefix NAL: parse prefix_nal_unit_svc() per F.7.3.2.12.1
                 if header.nal_ref_idc() != 0 {
-                    let store_ref_base_pic_flag = r.read_bool("store_ref_base_pic_flag")?;
+                    let store_ref_base_pic_flag = r.read_bit("store_ref_base_pic_flag")?;
                     let dec_ref_base_pic_marking = if store_ref_base_pic_flag {
                         Some(read_dec_ref_base_pic_marking(&mut r)?)
                     } else {
                         None
                     };
                     let additional_prefix_nal_unit_extension_flag =
-                        r.read_bool("additional_prefix_nal_unit_extension_flag")?;
+                        r.read_bit("additional_prefix_nal_unit_extension_flag")?;
                     Some(PrefixNalUnitRef {
                         store_ref_base_pic_flag,
                         dec_ref_base_pic_marking,

src/nal/sei/buffering_period.rs

@@ -36,8 +36,9 @@ fn read_cpb_removal_delay_list<R: BitRead>(
     let mut res = vec![];
     for _ in 0..count {
         res.push(InitialCpbRemoval {
-            initial_cpb_removal_delay: r.read(length, "initial_cpb_removal_delay")?,
-            initial_cpb_removal_delay_offset: r.read(length, "initial_cpb_removal_delay_offset")?,
+            initial_cpb_removal_delay: r.read_var(length, "initial_cpb_removal_delay")?,
+            initial_cpb_removal_delay_offset: r
+                .read_var(length, "initial_cpb_removal_delay_offset")?,
         });
     }
     Ok(res)