From 494d3f247e003bfd68147922d0525e553cb59ff8 Mon Sep 17 00:00:00 2001
From: skbeh <60107333+skbeh@users.noreply.github.com>
Date: Sun, 3 Aug 2025 13:25:00 +0000
Subject: [PATCH] feat: Improve codec selection

Refactors the video codec selection logic to be more robust. It now sorts streams by quality, codec preference, bandwidth,
and then by the full codec version string to ensure the best quality is chosen.
---
 biliarchiver/archive_bvid.py | 69 ++++++++++++++++++++++++++++--------
 1 file changed, 54 insertions(+), 15 deletions(-)

diff --git a/biliarchiver/archive_bvid.py b/biliarchiver/archive_bvid.py
index 7d2fd46..26a6470 100644
--- a/biliarchiver/archive_bvid.py
+++ b/biliarchiver/archive_bvid.py
@@ -2,7 +2,9 @@
 import os
 from pathlib import Path
 import re
+import string
 import traceback
+from typing import cast
 
 import aiofiles
 import httpx
@@ -93,6 +95,9 @@ async def archive_bvid(
     logined: bool = False,
     semaphore: asyncio.Semaphore,
 ):
+    def get_codec_version(codec: str) -> tuple[int, ...]:
+        return tuple(int("".join(char for char in ver if char in string.hexdigits), base=16) for ver in codec.split("."))
+
     async with semaphore:
         assert d.hierarchy is True, _("hierarchy 必须为 True")  # 为保持后续目录结构、文件命名的一致性
         assert d.client.cookies.get("SESSDATA") is not None, _(
@@ -168,21 +173,55 @@ def delete_cache(reason: str = ""):
             codec = None
             quality = None
             if video_info.dash:
-                # 选择编码 dvh->hev->avc
-                # 不选 av0 ，毕竟目前没几个设备能拖得动
-                codec_candidates = ["dvh", "hev", "avc"]
-                for codec_candidate in codec_candidates:
-                    for media in video_info.dash.videos:
-                        if media.codec.startswith(codec_candidate):
-                            codec = media.codec
-                            quality = media.quality
-                            print(f'{file_basename}: "{codec}" "{media.quality}" ...')
-                            break
-                    if codec is not None:
-                        break
-                assert (
-                    codec is not None and quality is not None
-                ), f"{file_basename}: " + _("没有 dvh、avc 或 hevc 编码的视频")
+                assert video_info.dash.videos, "Dash video streams not found"
+                assert all(media.codec and media.quality_id and media.bandwidth for media in video_info.dash.videos), (
+                    "All video streams must have codec, quality, and bandwidth information"
+                )
+
+                high_quality_codec_candidates = {"dvh", "hvc"}
+                all_codecs = {cast(str, media.codec)[:3] for media in video_info.dash.videos}
+                known_codecs = high_quality_codec_candidates.union({"avc", "hev", "av0"})
+                assert all_codecs.issubset(known_codecs), f"Unknown codecs found: {all_codecs - known_codecs}"
+
+                # First sort by quality, then codec preference, then bandwidth.
+                sorted_videos = sorted(
+                    [media for media in video_info.dash.videos if media.codec and media.quality_id and media.bandwidth],
+                    key=lambda m: (
+                        m.quality_id,
+                        cast(str, m.codec)[:3] in high_quality_codec_candidates,
+                        m.bandwidth,
+                    ),
+                    reverse=True,
+                )
+
+                if not sorted_videos:
+                    raise APIError(f"{file_basename}: " + _("没有可用的 dash 视频"), page.p_url)
+
+                # Get the properties of the best video after the initial sort.
+                top_candidate = sorted_videos[0]
+                target_codec_prefix = cast(str, top_candidate.codec)[:3]
+                target_quality = top_candidate.quality_id
+
+                # Filter videos to only those with the same quality and codec type.
+                candidates = [
+                    m
+                    for m in sorted_videos
+                    if m.quality_id == target_quality and cast(str, m.codec)[:3] == target_codec_prefix
+                ]
+
+                # Second sort by full codec version.
+                final_candidates = sorted(
+                    candidates,
+                    key=lambda m: get_codec_version(cast(str, m.codec)),
+                    reverse=True,
+                )
+
+                best_video = final_candidates[0]
+                codec = best_video.codec
+                quality = best_video.quality_id
+                assert codec is not None and quality is not None, f"{file_basename}: " + _("无法确定最佳视频编码与画质")
+
+                print(f'{file_basename}: "{codec}" "{best_video.quality}" ...')
             elif video_info.other:
                 # print(f"{file_basename}: 未解析到 dash 资源，交给 bilix 处理 ...")
                 print("{file_basename}: " + _("未解析到 dash 资源，交给 bilix 处理 ..."))