OpenTranscode/CHANGELOG.md

Changelog

All notable changes to OpenTranscode. Versions follow semantic versioning.

4.5.0 — 2026-07-26 (master)

Overview

Master release consolidating the v4.4.4 large-file fix with all prior v4.4.x stability work. Targets the "every large file fails" symptom reported on files from 1.1GB to 20GB, where the lossless pre-scale intermediate was exhausting the temp partition and presenting as cryptic ffmpeg error (rc=234) messages (the rc=234 was a truncated 300-char stderr snippet — the real error was "No space left on device").

Fixed — "ffmpeg error (rc=234)" on 10GB+ source files with scaling

• Pre-scale intermediate changed from CRF 0 to CRF 16. The old CRF-0 (mathematically lossless) libx265 intermediate produced 2-4× source size temp files: a 20GB BluRay rip generated a 60-80GB intermediate, exhausted the temp partition, and crashed. CRF 16 is visually lossless for archival purposes and produces 0.5-0.8× source size intermediates (a 20GB source → ~10-15GB intermediate instead of 60GB). The single 1.6GB→768MB file that succeeded in the user's batch was the only one small enough that the lossless intermediate fit on disk.
• New --inline-scale flag skips the pre-scale intermediate entirely. The scale/pad filter chain is passed directly to av1an via --ffmpeg-filter-args. Zero intermediate file, one fewer encode pass. Toggleable via the new "Inline scale (no intermediate)" checkbox in the UI options row. Default OFF — the intermediate path is more robust against av1an/VapourSynth filter-arg quirks on older builds. Enable when scaling large files (≥10GB) to save disk and time.
• The disk-space pre-check (_check_disk_space) now correctly handles the inline-scale path: no intermediate is created, so the 2-3× source temp-space warning is suppressed.

Carried forward from v4.4.x

• v4.4.3: AttributeError: 'EncoderWorker' object has no attribute 'verbose' crash on START in the launcher script. Added UI toggle for av1an (checkbox in the options row, equivalent to --use-av1an).
• v4.4.2: Live tail of av1an/ffmpeg stderr was spamming the log in quiet mode. "FAIL: av1an exit code 1" appeared even when the ffmpeg fallback succeeded (confusing "FAIL then OK" double-status).
• v4.4.1: Default log output reduced to two lines per file (start banner + finish status). Heartbeat and disk-space warnings require --verbose.
• v4.4.0: Per-file timeout raised from 2h to 24h (configurable via --timeout). 5%-of-source integrity check replaced with absolute 1KB minimum (false-positived on high-bitrate BluRay sources). Disk- space pre-check warns (not aborts) when free space < source size.

Tests added

• tests/test_inline_scale.py (13 tests): verifies the CLI flag, the launch_gui signature, the EncoderWorker.inline_scale attribute flow, the _prepare_input gating, the _encode_one --ffmpeg-filter-args injection, the CRF-16 (not CRF-0) intermediate, and that the launcher script mirror stays in sync.

Files touched in v4.4.4 (carried into 4.5.0)

• opentranscode/encoder_worker.py — CRF 16 + inline_scale gate + --ffmpeg-filter-args injection in av1an cmd.
• open-transcode.py — mirror of all the above (launcher script).
• opentranscode/cli.py — --inline-scale flag.
• opentranscode/ui_window.py — UI checkbox + launch_gui signature + state plumbing through env.av1an_flags["inline_scale"].
• opentranscode/__init__.py — launch_gui wrapper signature updated.

Upgrade notes

• Default behavior for files without a target resolution is unchanged — no intermediate is created either way.
• Default behavior for files with a target resolution is now CRF-16 intermediate (was CRF-0). Output quality is unchanged for archival purposes; intermediate size drops ~60-75%.
• For maximum speed on large files with scaling, enable --inline-scale or check the "Inline scale (no intermediate)" box in the UI. Test on a small file first if you're on an older av1an build (pre-0.5.2) to confirm --ffmpeg-filter-args is accepted.

4.4.4 — 2026-07-26

Fixed — "ffmpeg error (rc=234)" on 10GB+ source files with scaling

• Pre-scale intermediate changed from CRF 0 to CRF 16. The old CRF-0 (mathematically lossless) libx265 intermediate produced 2-4× source size temp files: a 20GB BluRay rip generated a 60-80GB intermediate, exhausted the temp partition, and crashed with cryptic ffmpeg error (rc=234) messages (the rc=234 came from a truncated 300-char stderr snippet — the real error was "No space left on device"). CRF 16 is visually lossless for archival purposes and produces 0.5-0.8× source size intermediates (a 20GB source → ~10-15GB intermediate instead of 60GB).
• New --inline-scale flag skips the pre-scale intermediate entirely. The scale/pad filter chain is passed directly to av1an via --ffmpeg-filter-args. Zero intermediate file, one fewer encode pass. Toggleable via the new "Inline scale (no intermediate)" checkbox in the UI options row. Default OFF — the intermediate path is more robust against av1an/VapourSynth filter-arg quirks on older builds. Enable when scaling large files (≥10GB) to save disk and time.
• The disk-space pre-check (_check_disk_space) now correctly handles the inline-scale path: no intermediate is created, so the 2-3× source temp-space warning is suppressed.

Tests added

• tests/test_inline_scale.py (13 tests): verifies the CLI flag, the launch_gui signature, the EncoderWorker.inline_scale attribute flow, the _prepare_input gating, the _encode_one --ffmpeg-filter-args injection, the CRF-16 (not CRF-0) intermediate, and that the launcher script mirror stays in sync.

4.4.3 — 2026-07-25

Fixed

• AttributeError: 'EncoderWorker' object has no attribute 'verbose' crash on START in the launcher script's EncoderWorker.__init__. The launcher script now sets self.verbose from env.av1an_flags["verbose"], matching the package's behavior.

Added

• UI toggle for av1an: a new "av1an (chunk-parallel)" checkbox in the options row. Default OFF = ffmpeg-only. The CLI flag --use-av1an still works; the UI toggle takes precedence when set.

Changed

• Documentation terminology: open-transcode.py is consistently called "the launcher script" (not "single-file script"). It mirrors the 16-module opentranscode/ package; calling it "single-file" was misleading.

4.4.2 — 2026-07-25

Fixed

• Live tail of av1an/ffmpeg stderr (│ Encoding: 1373/1376 Frames @ 51.70 fps...) was spamming the log in quiet mode in the launcher script. The package had this gated behind --verbose since v4.1.1; the launcher script now matches.
• "FAIL: av1an exit code 1" appeared in the log even when the ffmpeg fallback succeeded, producing a confusing "FAIL then OK" double-status. The av1an failure line now goes to _vlog (verbose only); the user sees only the final outcome (OK or FAIL: av1an + ffmpeg both failed).

4.4.1 — 2026-07-25

Changed

• Default log output reduced to two lines per file: start banner + finish status. Heartbeat (... 30s elapsed) and disk-space warnings now require --verbose. The user asked for "start + finish, nothing else"; this delivers exactly that.

4.4.0 — 2026-07-25

Added — massive-file support (30GB+ BluRay rips)

• Per-file timeout raised from 2h to 24h, configurable via --timeout SECONDS. A 30GB 1080p BluRay rip at SVT-AV1 preset 6 takes 4-10 hours; the old 2h timeout killed massive-file encodes partway through.
• 5%-of-source integrity check replaced with absolute 1KB minimum. The old check false-positived on high-bitrate sources (50GB BluRay → 5% = 2.5GB, but valid AV1 at CRF 32 produces 1-2GB for a 2-hour movie). The real integrity gate is the duration check (≥95% of source).
• Disk-space pre-check warns (not aborts) if free space < source size. When scaling, also checks the temp partition (lossless intermediate can be 2-3x source size).

Changed — log noise reduction

• Combined [N/total] filename banner + status into a single line: [1/180] filename.mkv — OK: 1.6MB -> 1.3MB (81%) (was two lines).
• Disk-space warnings no longer fire for skipped files (the check now runs after the skip-existing check).

4.3.0 — 2026-07-25

Added — skip-existing detection

• Probes the output file with ffprobe before encoding. If the output exists with a matching video+audio codec (and matching resolution when scaling is requested), the file is skipped. Default ON; use --force-reencode to disable.
• Added ffprobe_codec_name field to VideoCodecProfile and AudioProfile (av1/vp9/hevc, opus/vorbis/flac/iamf).
• Final summary now includes Skipped: N count.

Fixed — heartbeat regression

• v4.2.1 gated the 30-second heartbeat behind --verbose, causing the "hangs on first transcode, forever timer" symptom in quiet mode. The heartbeat is now always user-facing (one line per 30 seconds during long encodes). The live tail of frame= 67 fps= 12... stays gated.

4.2.1 — 2026-07-25

Changed — quiet mode by default

• Tech-detail log lines gated behind --verbose. Default output is two lines per file: start banner + finish status.
• Gated: CMD: lines, live tail of av1an/ffmpeg stderr, DIAGNOSIS blocks, resolution map, pre-flight validation table, heartbeat, disk-space warnings, RETRY messages, file-type detection details.

4.2.0 — 2026-07-25

Changed — ffmpeg is the default encode path

• av1an chunk-parallel was too fragile across distros (y4m pipe breaks, SvtAv1EncApp CLI rejects --threads, VapourSynth plugin issues, output buffering making it look hung). The default encode path is now ffmpeg-only. av1an is opt-in via --use-av1an.
• The av1an pre-flight smoke test is skipped entirely when av1an is not requested. _on_run_clicked sets use_ffmpeg_fallback = True directly, short-circuiting the av1an code path.

4.1.2 — 2026-07-25

Fixed

• Removed the --threads N injection into av1an's --video-params string (introduced in v4.1.0). SvtAv1EncApp (the standalone CLI av1an invokes per-chunk) does not accept --threads — only --lp (logical processors). The result was Unprocessed tokens: --threads → every chunk failed 3x → no av1an output. Thread capping now lives in av1an's --workers flag (chunk-parallel count) and in -threads for the ffmpeg fallback path (where libsvtav1 is a library).
• params_fn signature returned to (crf, preset) -> str (v4.0.0 form).

4.1.1 — 2026-07-25

Added

• Live progress tail — av1an's stdout/stderr emits to the GUI log as it arrives (handles both \n log lines and \r progress bar updates as line boundaries).
• 30-second heartbeat — ... still encoding (Xs elapsed) every 30 seconds so the user knows the encode is alive.

Changed

• IDEAL_THREADS_PER_WORKER raised from 4 to 6 for better per-chunk SVT-AV1 throughput. On a 28-thread Xeon, the split changed from 6×4=24 to 4×6=24 (same total, better per-chunk latency).

4.1.0 — 2026-07-25

Added — intelligent chunking

• _compute_intelligent_worker_count() computes (worker_count, threads_per_worker) such that worker_count * threads_per_worker <= logical_threads - 1. Prevents thread oversubscription on high-core- count machines (13 workers × 28 threads = 364 active on 28 logical CPUs → kernel scheduler drowned → hard lock).
• Per-encoder --threads N cap injected into --video-params.
• CLI flags --max-workers N and --threads-per-worker N for overrides.

4.0.0 — 2026-07-25

Fixed — "works up until near the end, never saves chunks into a full file"

• av1an auto-selects the Hybrid chunk method when no VapourSynth source plugins are installed. Hybrid fails on phone-recorded MP4s with sparse keyframes (scene boundaries rarely align with I-frames → segment muxer splits mid-GOP → decoder errors → y4m pipe breaks → encoder reads EOF → every chunk fails after 3 retries → no output file).
• env_probe now probes for VapourSynth source plugins (lsmash, ffms2, bestsource, dgdecnv). When none are found, pre-sets chunk_method_override = "select" to avoid the wasted first attempt.
• _encode_one accepts a chunk_method parameter for retry. When av1an fails with the y4m break pattern, it recursively retries with --chunk-method select and caches that choice for subsequent files.
• --chunk-method {auto,select,hybrid,segment,ffms2,lsmash,bestsource,dgdecnv} CLI flag for forcing a specific chunk method.

Package split

• Refactored the monolithic open-transcode.py into a 16-module opentranscode/ package. The launcher script is preserved for backwards compatibility and as the test target for mocked tests.
• pyproject.toml for pip install -e . and python -m build.

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