feat(iori): support discontinued parts

[Yesterday17]

No description provided.

[Copilot]

Pull request overview

This PR adds support for discontinued parts in HLS streaming by introducing a part_index field to track segments across discontinuity boundaries. This enables proper handling of streams that have been split into multiple parts due to stream discontinuities.

Key changes:

• Added part_index field to SegmentInfo and related structures to track segment parts
• Updated HLS parsers to calculate part_index based on discontinuity markers
• Modified merge implementations (proxy, pipe, concat, auto) to handle multi-part outputs

Reviewed changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
flake.lock	Updated nixpkgs and rust-overlay dependencies
crates/iori/src/lib.rs	Added part_index() method to StreamingSegment trait with default value of 0
crates/iori/src/segment.rs	Added part_index field to SegmentInfo struct and implemented forwarding in trait implementations
crates/iori/src/hls/segment.rs	Added part_index field to M3u8Segment and implemented part_index() method
crates/iori/src/hls/source.rs	Populated part_index field when creating segments from playlist
crates/iori-hls/src/parse.rs	Implemented logic to track and increment current_part_index based on discontinuity tags
crates/iori-hls/src/models.rs	Added part_index field to MediaSegment and discontinuity_sequence to MediaPlaylist
crates/iori-hls/src/m3u8_rs.rs	Updated conversion from m3u8_rs types to track part_index based on discontinuity markers
crates/iori/src/merge/proxy.rs	Modified playlist generation to insert discontinuity markers based on part_index changes
crates/iori/src/merge/pipe.rs	Updated message passing to include part_index and handle part transitions in file output
crates/iori/src/merge/concat.rs	Refactored to sort by part_index and create separate output files per part
crates/iori/src/merge/auto.rs	Restructured to process segments grouped by part_index and generate multiple output files
crates/iori-hls/tests/fixtures/archive_02.m3u8	Added test fixture for playlist with discontinuity
crates/iori-hls/tests/cases.rs	Added test case for archive_02 fixture and renamed existing test

Comments suppressed due to low confidence (1)

crates/iori/src/merge/proxy.rs:219

• The discontinuity sequence calculation is incorrect. The EXT-X-DISCONTINUITY-SEQUENCE tag should indicate the discontinuity sequence number of the first media segment in the playlist. However, this code is calculating the total number of discontinuities encountered and inserting it as the discontinuity sequence value.

In HLS, the discontinuity sequence should represent the sequence number of the discontinuity that applies at the start of the playlist. Since discontinuities are being added inline as segments are iterated, the initial discontinuity sequence should be based on the first segment's part_index, not the count of discontinuities. If you're tracking parts with a part_index starting at the discontinuity_sequence value, the first segment's part_index should be used as the discontinuity sequence value.

    // Add discontinuity sequence at the beginning if there were any discontinuities
    if discontinuity_sequence > 0 {
        let header = format!("#EXT-X-DISCONTINUITY-SEQUENCE:{}\n", discontinuity_sequence);
        // Insert after version line
        let parts: Vec<&str> = playlist.split("#EXT-X-VERSION:3\n").collect();
        playlist = format!("{}#EXT-X-VERSION:3\n{}{}", parts[0], header, parts[1]);
    }

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[Copilot]

The variable output is declared but never used after initialization. It's set to None at line 101 and never read or written to again in the function. This appears to be dead code that should be removed.

Suggested change

let mut output: Option<File> = None;

[Copilot]

The discontinuity detection logic updates prev_part_index even when a segment has failed and is skipped from the playlist. This means that if a failed segment causes a part_index change, the discontinuity marker won't be inserted before the next successful segment with a different part_index. The prev_part_index should only be updated when the segment is actually included in the playlist (i.e., when !current_failed).

[Copilot]

Pull request overview

Copilot reviewed 13 out of 14 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

crates/iori/src/merge/proxy.rs:218

• The logic for adding the EXT-X-DISCONTINUITY-SEQUENCE tag is incorrect. According to the HLS specification, EXT-X-DISCONTINUITY-SEQUENCE should indicate the discontinuity sequence number of the first media segment in the playlist, not the total count of discontinuities. The current implementation counts the total number of discontinuities and inserts that count, which would be incorrect if the playlist doesn't start from the beginning. The discontinuity_sequence should track the starting value, not be incremented for each discontinuity encountered.

    // Add discontinuity sequence at the beginning if there were any discontinuities
    if discontinuity_sequence > 0 {
        let header = format!("#EXT-X-DISCONTINUITY-SEQUENCE:{}\n", discontinuity_sequence);
        // Insert after version line
        let parts: Vec<&str> = playlist.split("#EXT-X-VERSION:3\n").collect();
        playlist = format!("{}#EXT-X-VERSION:3\n{}{}", parts[0], header, parts[1]);

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