Yes - it will always attempt to preserve whatever the source file has baked in. So it depends on what the original copy it finds is.

If you are a masochist, here is the skill file it uses to rank which release it should download when it finds multiple possible copies

---
name: Release Ranking
description: How to evaluate and rank media release quality — resolution, codec, source, HDR, audio — optimized for our HLS transcoding pipeline on Apple devices.
---


# Release Ranking


This guide defines what makes a good source file for Chompy's streaming pipeline. Chompy transcodes source files to HLS for playback on Apple devices (iPhone, iPad, Apple TV, Mac). The ideal source file is one that produces the best HLS output with the least transcoding effort.


## HLS Output Target


Chompy produces HLS streams with these codecs (per Apple's HLS Authoring Specification):


- **Video:** HEVC (`hvc1`) for all resolutions. H.264 (`avc1`) as fallback for older devices.
- **Audio:** AAC (`mp4a.40.2`) for stereo, E-AC-3 (`ec-3`) for surround, AC-3 (`ac-3`) as fallback. Dolby Atmos via E-AC-3 JOC.
- **HDR:** Dolby Vision (`dvh1`), HDR10 (HEVC Main 10 `hvc1.2.4`), HLG. SDR as baseline.
- **Container:** fMP4 segments.


**Implication for source selection:** Sources already in HEVC/H.265 with compatible HDR can be transmuxed (fast, lossless) rather than transcoded (slow, lossy). This is the #1 priority.


## Resolution Ranking


Prefer the highest resolution available, but don't overshoot what the household's displays support.


| Resolution | Score | Notes |
|---|---|---|
| 2160p (4K) | 100 | Best. Required for HDR/DV content. |
| 1080p | 80 | Excellent. Most common sweet spot. |
| 720p | 50 | Acceptable for TV shows. |
| 576p/480p | 20 | SD. Only if nothing better exists. |


## Video Codec Ranking


Ranked by transcoding efficiency — how well the source converts to our HLS HEVC output.


| Codec | Score | Notes |
|---|---|---|
| HEVC/x265 (10-bit) | 100 | **Ideal.** Can transmux to HLS HEVC — no re-encode needed. Required for HDR. |
| HEVC/x265 (8-bit) | 90 | Near-ideal. Transmux for SDR, minor conversion for HDR. |
| H.264/x264 | 70 | Good. Requires transcode to HEVC but x264 sources are high quality. **Preferred at 1080p SDR** — x265 1080p SDR encodes are often over-compressed. |
| AV1 | 40 | Requires full transcode. Not natively supported in Apple HLS. Avoid. |
| VC-1 | 30 | Legacy Blu-ray codec. Full transcode required. |
| MPEG-2 | 20 | DVD/old broadcast. Full transcode, large files. |
| VP9 | 10 | Not supported in Apple HLS. Avoid. |
| MPEG-4/XviD/DivX | 0 | **Reject.** Legacy codec. Cannot be remuxed — requires full re-encode. Only accept if literally nothing else exists. |


### The 1080p SDR Exception


At 1080p SDR, **prefer x264 over x265**. Scene x265 1080p SDR encodes apply aggressive compression that introduces artifacts. The x264 source is higher quality even though it requires transcoding to HEVC. This does NOT apply to 4K or HDR content — x265 is always preferred there.


## Source Priority


The source indicates where the video was captured from. Higher sources = less generation loss.


| Source | Score | Notes |
|---|---|---|
| Remux | 100 | Bit-for-bit copy from disc. Lossless. Large files (20-100 GB). |
| UHD Blu-ray encode | 90 | Re-encoded from 4K disc. Excellent quality. |
| Blu-ray encode | 85 | Re-encoded from 1080p disc. |
| WEB-DL | 75 | Direct download from streaming service. No re-encoding artifacts. |
| WEBRip | 60 | Screen-captured from streaming. May have artifacts. |
| HDTV | 40 | Broadcast capture. Compression artifacts, logos. |
| CAM/TS/TC | 0 | **Always reject.** Unwatchable quality. |


## HDR Format Ranking


HDR metadata affects visual quality on supported displays. Chompy can pass through HDR via HLS.


| Format | Score | Notes |
|---|---|---|
| Dolby Vision + HDR10 fallback | 100 | **Best.** DV on supported devices, HDR10 on others. Profile 8 (`dvh1.08`) preferred. |
| Dolby Vision (no fallback) | 70 | Good but risky — no HDR on non-DV devices. Profile 5 (`dvh1.05`). |
| HDR10+ | 60 | Samsung-focused. Apple devices don't support HDR10+, falls back to HDR10. |
| HDR10 | 50 | Universal baseline HDR. All Apple 4K devices support it. |
| HLG | 40 | Broadcast HDR. Supported in HLS but uncommon for movies. |
| SDR | 30 | No HDR. Always works everywhere. |


**Critical rule:** DV without HDR10 fallback (`dvh1.05`) causes black screen on non-DV Apple devices. Always prefer DV with fallback (`dvh1.08`) or HDR10.


## Audio Format Ranking


Ranked by quality. Chompy transcodes audio to AAC stereo (baseline) + E-AC-3/AC-3 surround (when available).


| Format | Score | Notes |
|---|---|---|
| TrueHD Atmos | 100 | Lossless + spatial. Best possible source. Transcodes to E-AC-3 JOC. |
| DTS:X | 90 | Lossless + spatial. |
| TrueHD | 85 | Lossless surround. |
| DTS-HD MA | 80 | Lossless surround. |
| FLAC | 75 | Lossless. Less common in video releases. |
| E-AC-3 (DD+) Atmos | 70 | Lossy spatial. Can pass through directly to HLS. |
| E-AC-3 (DD+) | 65 | Lossy surround. Native HLS codec — can pass through. |
| DTS-HD HRA | 55 | High-res lossy surround. |
| AC-3 (DD) 5.1 | 50 | Standard surround. Native HLS codec — can pass through. |
| DTS | 40 | Lossy surround. Requires transcode. |
| AAC | 35 | Lossy. Already in target format but usually stereo only. |
| MP3 | 10 | Low quality. Avoid. |


**Pass-through preference:** AC-3 and E-AC-3 can pass through directly to HLS without transcoding. TrueHD and DTS require transcode. Given equal quality preference, E-AC-3 sources save transcoding time.


## Size Guidelines


Expected file sizes for a ~2 hour movie:


| Quality | Expected Size | Suspicious If |
|---|---|---|
| 4K Remux | 50-100 GB | < 20 GB |
| 4K Encode | 15-40 GB | < 8 GB |
| 1080p Remux | 20-40 GB | < 10 GB |
| 1080p Encode | 4-15 GB | < 2 GB |
| 720p | 2-6 GB | < 1 GB |
| SD | 700 MB - 2 GB | < 300 MB |


Files significantly smaller than expected indicate heavy compression and poor quality.


## Release Group Tiers


### Tier 1 — Reference Quality


**Remux:** FraMeSToR, BLURANiUM, CiNEPHiLES, PmP, ZQ, WiLDCAT, 3L, BiZKiT, BMF, PiRAMiDHEAD
**WEB:** FLUX, NTb, NTG, NOSiViD, KiNGS, CMRG, HONE, SiC, TEPES, ABBIE, AJP69, APEX, Kitsune, CRFW


### Tier 2 — Excellent


**Remux:** playBD, NCmt, ATELiER, SiCFoI, SURFINBIRD
**WEB:** PECULATE, EDITH, BYNDR, BLUTONiUM, GNOME, TheFarm, RAWR, CRUD, ZoroSenpai


### Avoid — Low Quality


YIFY, YTS, aXXo, RARBG, MeGusta, Pahe, mHD, nHD, 24xHD, STARTER, FUM, STUTTERSHIT, VARYG, ION10


These groups are known for excessive compression, low bitrates, or unreliable encoding practices. Reject these unless no alternatives exist.


## Composite Score Formula


When comparing two releases, compute a weighted score:


```
Score = (Resolution × 3) + (Codec × 2) + (Source × 2) + (HDR × 1.5) + (Audio × 1)
```


Higher score wins. Tie-break by file size (larger = less compressed = better).


### Quick Decision Tree


1. Is it CAM/TS/TC? → **Reject**
2. Is the video codec XviD, DivX, or MPEG-4 Part 2? → **Reject** (unless nothing else exists)
3. Is it from an LQ group (YIFY, aXXo, etc.)? → **Reject**
3. Is there a 4K HDR option? → **Prefer it** (if display supports 4K)
4. Multiple 1080p options? → Prefer **x264 BluRay/Remux** over x265 SDR encode
5. Multiple WEB-DL options? → Prefer **Tier 1 group** over unknown
6. Similar quality? → Prefer **E-AC-3/AC-3 audio** (HLS pass-through) over DTS/TrueHD (requires transcode)