211 lines
13 KiB
Markdown
211 lines
13 KiB
Markdown
# Pre-Compact Handoff — Session 2026-05-14 (FINAL post iter38)
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Use this doc to resume the fresnel-fourier campaign after Claude context compaction. **Campaign at definitive close: 5/5 codecs PASS in a single libva session, no env-override required.**
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## TL;DR
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| Bug / Item | Status | Fix iter |
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|---|---|---|
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| Bug 4 (H.264 keyframe-partial) | **FIXED** | iter25 α-25 (rkvdec image_fmt pre-seed via synthetic SPS at CreateContext) |
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| Bug 5 (HEVC libva all-zero CAPTURE) | **FIXED** | iter25 α-25 (frame 1) + iter31 α-29 (frames 2+: slice_params.short_term_ref_pic_set_size from VAAPI st_rps_bits) |
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| VP8 wrong output through libva | **FIXED** | iter33 α-30 (prepend 10/3 byte VP8 uncompressed header to OUTPUT — ffmpeg-vaapi strips it) |
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| MPEG-2 HW differs from SW | **NOT A BUG** | hantro IDCT precision (≤3 LSB / pixel, SSIM > 0.9999); libva == kdirect bit-exact |
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| Kernel diagnostic printks | **CLEANED** | iter32 (7.0-11) + iter34 (7.0-14) |
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| Env-gated DIAG probes (iter29/30/33/35) | **CLEANED** | iter36 (-131 / +7 LOC) |
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| α-26 mis-routed cosmetic | **REVERTED** | iter37 (1-line; rkvdec never read that field) |
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| Libva multi-device probe | **DONE** | iter38 (single session serves all 5 codecs; no env override needed) |
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| Codec | libva 10F sha | kdirect 10F sha | SW 10F sha | L==K | L==SW |
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|---|---|---|---|---|---|
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| H.264 | dd4f5f2d552c07bc | same | same | ✓ | ✓ |
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| HEVC | 108f925bb6cbb6c9 | same | same | ✓ | ✓ |
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| VP9 | cf35908ae0f9ab60 | same | same | ✓ | ✓ |
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| VP8 | d3231e5b6c0ee10b | same | same | ✓ | ✓ |
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| MPEG-2| 95c5905890c937d4 | same | 933b744134e47ba4 | ✓ | ~ (≤3 LSB IDCT precision) |
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**5/5 PASS** the libva-vs-kdirect bit-exact correctness contract. 4/5 also bit-equal SW.
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`vainfo` with NO env override enumerates the union of profiles from rkvdec + hantro:
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```
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v4l2-request: auto-selected codec device: /dev/video3 + /dev/media1
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v4l2-request: iter38: also opened hantro-vpu decoder at /dev/video2 + /dev/media0
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vainfo: Supported profile and entrypoints
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VAProfileMPEG2Simple : VAEntrypointVLD
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VAProfileMPEG2Main : VAEntrypointVLD
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VAProfileH264Main : VAEntrypointVLD
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VAProfileH264High : VAEntrypointVLD
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VAProfileH264ConstrainedBaseline: VAEntrypointVLD
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VAProfileH264MultiviewHigh : VAEntrypointVLD
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VAProfileH264StereoHigh : VAEntrypointVLD
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VAProfileHEVCMain : VAEntrypointVLD
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VAProfileVP8Version0_3 : VAEntrypointVLD
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VAProfileVP9Profile0 : VAEntrypointVLD
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```
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## Substrate state
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| Component | Location | Tip |
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|---|---|---|
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| Campaign repo (this) | `/home/mfritsche/src/fresnel-fourier/` | `ba4b6fd` on gitea master |
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| Libva backend fork (noether) | `/home/mfritsche/src/libva-multiplanar/libva-v4l2-request-fourier/` | `7ac934e` on gitea master |
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| Libva backend (fresnel deploy) | `/home/mfritsche/src/libva-v4l2-request-fourier/` | sync to gitea master, `ninja -C build` |
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| Kernel source (boltzmann) | `~/src/kernel-agent-bootstrap/build/marfrit-packages/arch/linux-fresnel-fourier/` | pkgrel=14 clean |
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| Kernel running on fresnel | `linux-fresnel-fourier 7.0-14` | clean shipping kernel, no diagnostic printks |
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| Test fixtures (fresnel) | `/home/mfritsche/fourier-test/bbb_*.{mp4,ts,webm}` | 5 codecs at 720p10s or 1080p30 |
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| Memory | `~/.claude/projects/-home-mfritsche-src-fresnel-fourier/memory/` | see entries below |
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## Identity for gitea pushes
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All `git.reauktion.de` interactions use the `claude-noether` identity (per memory `feedback_gitea_as_claude_noether.md`). Backend remote URL: `ssh://gitea@git.reauktion.de.claude-noether/marfrit/libva-v4l2-request-fourier.git`.
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## Device map on 7.0-14
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`/dev/video*` and `/dev/media*` numbers SHIFT between kernel boots based on probe order. On the current 7.0-14 boot:
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| Driver | /dev/videoN | /dev/mediaN |
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|---|---|---|
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| rockchip-rga | video0 | n/a |
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| rk3399-vpu-enc | video1 | (shared) |
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| rk3399-vpu-dec (hantro) | **video2** | **media0** |
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| rkvdec | **video3** | **media1** |
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`v4l2-ctl --info` + `media-ctl -p` if mapping uncertain on a fresh boot. Iter38 makes this irrelevant for typical use — libva auto-probes both.
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## Backend commits delivered (chronological, this campaign day)
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```
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7ac934e iter38b: bounds check uses MAX_PROFILES (11), not MAX_CONFIG_ATTRIBUTES (10)
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c56a77b iter38: multi-device probe — single libva session serves all 5 codecs ← architectural close
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25d3e5f iter37: revert α-26 — decode_params.short_term_ref_pic_set_size back to 0
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7db15a5 iter36: remove env-gated DIAG probes (iter29/30/33/35)
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48fd028 iter35 DIAG: env-gated dump of v4l2_ctrl_mpeg2_* contents (removed iter36)
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7e0848d iter33 α-30: prepend VP8 uncompressed frame header to OUTPUT buffer ← VP8 fix
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bf3e3d8 iter33: extend VP8 DIAG to dump VAAPI probability struct directly (removed iter36)
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4b3c21b iter33 DIAG: env-gated dump of v4l2_ctrl_vp8_frame contents (removed iter36)
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23eb1bd iter31 α-29: slice_params.short_term_ref_pic_set_size = picture->st_rps_bits ← HEVC fix
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68dbbdd iter30 DIAG: LIBVA_TS_SCALE env-gated timestamp multiplier (removed iter36)
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0eca3ff iter29 DIAG: env-gated dump of HEVC slice_data trailing 80 bytes (removed iter36)
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6646b16 Revert iter28b DIAG: trim=40 universal-trim broke IDR frame 1
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cd286d9 iter28 α-28: bit_size = (slice_data_size - data_byte_offset) * 8 for HEVC
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754be1d iter27 diag: env-gated VAAPI slice fields dump
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719d813 iter27 α-27: populate slice_params.num_entry_point_offsets (no-op)
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66ef848 iter26 α-26: decode_params.short_term_ref_pic_set_size from VAAPI (reverted iter37)
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d062fec iter25 α-25 fix: FRAME_MBS_ONLY flag for H264 dummy SPS
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db0b7f9 iter25 α-25: inject synthetic SPS before cap_pool_init to seed image_fmt ← H264+HEVC frame 1 fix
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```
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Load-bearing commits: `db0b7f9 + d062fec` (α-25), `23eb1bd` (α-29), `7e0848d` (α-30), `c56a77b + 7ac934e` (iter38 multi-device).
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## Campaign repo commits delivered (today's arc)
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```
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ba4b6fd iter38 close: multi-device probe — 5/5 codecs in one libva session
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7e3eadf iter36 close: env-gated DIAG removed, 5/5 PASS retained
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7c06c51 iter35 close: MPEG-2 verified libva-correct; HW IDCT precision intrinsic
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70ddbd6 iter34 close: kernel 7.0-14 CLEAN ship — 5/5 codecs PASS
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cd2d077 iter33: MPEG-2 closed (libva==kdirect bit-exact) — 5/5 codecs PASS
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51eee19 iter33 α-30 close: VP8 FIXED — 4/5 codecs PASS
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acacf3d iter32 close: kernel substrate cleanup landed → 7.0-11 SHIPPING
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85cc178 Update campaign session doc: full-day arc closes at 3/3 PASS
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fde8a25 Update handoff doc: HEVC Bug 5 fully fixed (3/3 PASS)
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c1f9738 iter31 α-29 close: HEVC Bug 5 remainder FIXED — 3/3 PASS
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422ecaf Add pre-compact handoff doc for session resumption
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… earlier in day: c15fc6c, 8b17bf7, 02c4192, bf67900 (iter20-28 chain)
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```
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## How to verify the current state
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Run on fresnel (post-7.0-14 boot, no env override needed):
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```bash
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for codec in h264:bbb_1080p30_h264.mp4 hevc:bbb_720p10s_hevc.mp4 vp9:bbb_720p10s_vp9.webm vp8:bbb_720p10s_vp8.webm mpeg2:bbb_720p10s_mpeg2.ts; do
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name="${codec%%:*}"; fixture="${codec#*:}"
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env LIBVA_DRIVER_NAME=v4l2_request \
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LIBVA_DRIVERS_PATH=/home/mfritsche/src/libva-v4l2-request-fourier/build/src \
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ffmpeg -hide_banner -loglevel error -y \
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-hwaccel vaapi -hwaccel_output_format vaapi \
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-i "/home/mfritsche/fourier-test/$fixture" \
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-vf "hwdownload,format=nv12" -frames:v 10 \
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-f rawvideo -pix_fmt nv12 "/tmp/L_${name}.yuv"
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ffmpeg -hide_banner -loglevel error -y -hwaccel v4l2request -hwaccel_output_format drm_prime \
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-i "/home/mfritsche/fourier-test/$fixture" -vf "hwdownload,format=nv12" \
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-frames:v 10 -f rawvideo -pix_fmt nv12 "/tmp/K_${name}.yuv"
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L=$(sha256sum "/tmp/L_${name}.yuv" | cut -c1-16)
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K=$(sha256sum "/tmp/K_${name}.yuv" | cut -c1-16)
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[ "$L" = "$K" ] && echo "$name: PASS" || echo "$name: FAIL"
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done
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```
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Expect: 5× PASS.
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## Root cause summary
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**Bug 4 + Bug 5 frame 1 (iter25 α-25)**: `rkvdec_s_ctrl` returns -EBUSY when first SPS triggers image_fmt reset on a busy CAPTURE queue. libva pre-allocated 24 CAPTURE buffers at CreateContext (iter5b-β design) before per-frame S_EXT_CTRLS. Fix: inject synthetic SPS at CreateContext, pre-cap_pool_init, while CAPTURE is still empty.
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**Bug 5 frame 2+ (iter31 α-29)**: libva backend set `slice_params->short_term_ref_pic_set_size = 0` (stale "VAAPI doesn't expose" comment). rkvdec's `assemble_sw_rps` (rkvdec-hevc.c:386-389) reads this; when zero with `num_short_term_ref_pic_sets <= 1`, falls back to 0 → entropy decoder consumes slice-header bits as long-term-RPS → garbage for every non-IDR slice. IDR is gated by `!IDR_PIC` so frame 1 was unaffected. Fix: `slice_params->short_term_ref_pic_set_size = picture->st_rps_bits` (VAAPI's field IS the slice-header bit count, per `va_dec_hevc.h` doc). α-26 had mis-routed this value into `decode_params` (same field name in V4L2, different semantics — SPS-side bit count) — reverted in iter37.
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**VP8 (iter33 α-30)**: ffmpeg-vaapi strips the VP8 uncompressed frame header (3 bytes interframe / 10 bytes keyframe) before submitting via VAAPI. ffmpeg-v4l2request keeps it. Hantro hard-codes `first_part_offset = V4L2_VP8_FRAME_IS_KEY_FRAME(hdr) ? 10 : 3` and uses it for both `mb_offset_bits` and `dct_part_offset`. Without the prepended header in libva's OUTPUT, hantro's offset arithmetic lands inside the compressed bitstream and the entropy decoder produces garbage. Fix: in `codec_store_buffer`, prepend `header_size` zero bytes to OUTPUT for VP8 profile (hantro skips these bytes for actual parsing, uses ctrl-struct values).
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**Multi-device probe (iter38)**: VA_DRIVER_INIT opens BOTH rkvdec + hantro fds. `RequestCreateConfig` retargets `driver_data->{video,media}_fd` to the right device per profile (tearing down pools on switch). `RequestQueryConfigProfiles` unions across all open fds. iter38b fixed a latent off-by-one: bounds checks used `MAX_CONFIG_ATTRIBUTES` (10) but profile array is sized by `MAX_PROFILES` (11) — pre-iter38 never returned more than 9 profiles so the bug never bit.
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## Open items (low priority, optional polish)
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1. **Multi-context simultaneously** — current design supports only one decode context at a time across devices (device switch tears down pools). Could be expanded to per-context pools to support simultaneous mixed-codec decode. Not requested.
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2. **Sub-profile support** — H264 Hi10P, HEVC Main10, VP9 Profile 2 are HW-supported on RK3399 but the libva backend has no entries in `pixelformat_for_profile` and elsewhere. Out of scope for this campaign.
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## Memory entries (full campaign set)
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- `feedback_rkvdec_image_fmt_pre_seed.md` — α-25 (Bug 4 + Bug 5 frame 1)
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- `feedback_va_st_rps_bits_is_slice_field.md` — α-29 (Bug 5 frame 2+)
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- `feedback_vaapi_strips_vp8_uncompressed_header.md` — α-30 (VP8)
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- `feedback_mpeg2_hw_sw_idct_precision.md` — MPEG-2 PASS criterion = libva==kdirect (HW vs SW gap intrinsic per spec)
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- `feedback_multi_device_probe_design.md` — iter38 dual-fd architecture + MAX_PROFILES bounds gotcha
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- `feedback_libva_byte_correct_kernel_bug.md` — **FULLY OVERTURNED** (both Bug 4 + Bug 5 are libva-side fixes)
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- `reference_fresnel_kernel_substrate.md` — 7.0-14 clean, device-enumeration-shift caveat
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- MEMORY.md index updated
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## Key commands quickreference
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```bash
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# Sync backend on fresnel + rebuild
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ssh fresnel 'cd ~/src/libva-v4l2-request-fourier && git fetch && git reset --hard origin/master && ninja -C build'
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# 5-codec smoke (above script). Each codec ~5s.
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# Identify which video device is rkvdec vs hantro after a fresh boot
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ssh fresnel 'for v in /dev/video*; do v4l2-ctl -d $v --info 2>/dev/null | grep -E "^Card type" | head -1 | awk -v dev=$v "{print dev,\$0}"; done'
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# vainfo (auto-detects + opens both decoders since iter38)
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ssh fresnel 'env LIBVA_DRIVER_NAME=v4l2_request \
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LIBVA_DRIVERS_PATH=/home/mfritsche/src/libva-v4l2-request-fourier/build/src \
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vainfo'
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# kdirect reference (works for any codec; hwaccel auto-routes)
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ssh fresnel 'ffmpeg -hide_banner -loglevel error -y -hwaccel v4l2request -hwaccel_output_format drm_prime \
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-i /home/mfritsche/fourier-test/bbb_720p10s_hevc.mp4 \
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-vf "hwdownload,format=nv12" -frames:v 10 -f rawvideo -pix_fmt nv12 /tmp/y.yuv'
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# Force single-device mode (skip iter38 alt-probe)
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env LIBVA_V4L2_REQUEST_VIDEO_PATH=/dev/video3 LIBVA_V4L2_REQUEST_MEDIA_PATH=/dev/media1 ...
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# Reboot fresnel (sddm autologin reseats mfritsche)
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ssh fresnel 'sudo systemctl reboot'; sleep 60
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```
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## Safe vs needs-confirmation actions
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**Safe (no confirmation needed)**:
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- Read/grep on noether, boltzmann, fresnel
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- Push to gitea (claude-noether identity)
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- Reboot fresnel (sddm autologin restores session)
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- Build kernel on boltzmann via `makepkg -ef --skipinteg --noconfirm`
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- Deploy kernel via `scp` + `sudo pacman -U`
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- Run ffmpeg/cmp tests on fresnel
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**Needs confirmation**:
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- Significant rebuild (~25-30 min CPU on boltzmann, e.g. ffmpeg full rebuild or fresh kernel build)
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- Per-context pool refactor (item 1 — would allow simultaneous mixed-codec decode but is invasive)
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- Sub-profile rollout (item 2)
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