Refine seller store implementation

2026-08-31 14:37:28 +08:00
parent 957289f717
commit 2a667b4f3b
27 changed files with 1650 additions and 624 deletions
@@ -0,0 +1,187 @@
+"""用 FFmpeg 合成平台兼容的无音轨商品轮播视频。"""
+from __future__ import annotations
+
+import asyncio
+import json
+import os
+import tempfile
+from collections.abc import Awaitable, Callable
+from dataclasses import dataclass
+from pathlib import Path
+
+from config import get_settings
+from services.storage import (
+    ResourceSizeLimitError,
+    download_bytes,
+    image_extension,
+    local_path,
+    normalize_image_bytes,
+    read_local_bytes,
+)
+
+
+class VideoRenderError(RuntimeError):
+    """FFmpeg 无法生成符合预设的商品视频。"""
+
+
+class VideoRenderCancelled(VideoRenderError):
+    """任务在 FFmpeg 运行期间被用户取消。"""
+
+
+@dataclass(frozen=True)
+class RenderedVideo:
+    data: bytes
+    duration_seconds: float
+    width: int
+    height: int
+
+
+def slide_seconds_for(count: int) -> float:
+    """按图片数量维持约 9–13 秒成片，并确保两图时也不会过短。"""
+    by_count = {2: 4.5, 3: 3.5, 4: 3.0, 5: 2.8}
+    try:
+        return by_count[count]
+    except KeyError as exc:
+        raise VideoRenderError("轮播视频只支持 2–5 张图片") from exc
+
+
+async def _read_image(url: str) -> tuple[bytes, str]:
+    path = local_path(url)
+    if path is not None:
+        return read_local_bytes(path), ""
+    return await download_bytes(url, max_bytes=get_settings().image_download_max_bytes)
+
+
+async def _run_process(
+    args: list[str],
+    *,
+    should_cancel: Callable[[], Awaitable[bool]],
+    timeout_seconds: int,
+) -> None:
+    process = await asyncio.create_subprocess_exec(
+        *args,
+        stdout=asyncio.subprocess.DEVNULL,
+        stderr=asyncio.subprocess.PIPE,
+    )
+    try:
+        waited = 0.0
+        while process.returncode is None:
+            if await should_cancel():
+                process.terminate()
+                try:
+                    await asyncio.wait_for(process.wait(), timeout=5)
+                except TimeoutError:
+                    process.kill()
+                    await process.wait()
+                raise VideoRenderCancelled("视频任务已取消")
+            await asyncio.sleep(0.25)
+            waited += 0.25
+            if waited > timeout_seconds:
+                process.kill()
+                await process.wait()
+                raise VideoRenderError(f"视频渲染超过 {timeout_seconds} 秒，请减少图片后重试")
+        stderr = (await process.stderr.read()).decode("utf-8", errors="replace") if process.stderr else ""
+        if process.returncode != 0:
+            raise VideoRenderError(f"FFmpeg 渲染失败：{stderr[-800:] or '未知错误'}")
+    finally:
+        if process.returncode is None:
+            process.kill()
+            await process.wait()
+
+
+async def _probe(path: Path) -> dict:
+    settings = get_settings()
+    process = await asyncio.create_subprocess_exec(
+        settings.video_ffprobe_path,
+        "-v", "error", "-show_entries", "format=duration,size:stream=codec_name,width,height,pix_fmt",
+        "-of", "json", str(path),
+        stdout=asyncio.subprocess.PIPE,
+        stderr=asyncio.subprocess.PIPE,
+    )
+    stdout, stderr = await process.communicate()
+    if process.returncode != 0:
+        raise VideoRenderError(f"无法校验视频输出：{stderr.decode('utf-8', errors='replace')[-400:]}")
+    try:
+        return json.loads(stdout)
+    except json.JSONDecodeError as exc:
+        raise VideoRenderError("FFprobe 未返回可解析的视频信息") from exc
+
+
+async def render_slideshow(
+    source_urls: list[str],
+    *,
+    should_cancel: Callable[[], Awaitable[bool]],
+) -> RenderedVideo:
+    """将已入库图片缩放留白后串为 MP4，严禁接收调用方任意命令参数。"""
+    settings = get_settings()
+    if not settings.video_ffmpeg_path or not settings.video_ffprobe_path:
+        raise VideoRenderError("未配置 FFmpeg 或 FFprobe 可执行路径")
+    count = len(source_urls)
+    seconds = slide_seconds_for(count)
+    transition = settings.video_transition_seconds
+
+    with tempfile.TemporaryDirectory(prefix="osk-video-") as temp_dir:
+        workdir = Path(temp_dir)
+        inputs: list[Path] = []
+        for index, url in enumerate(source_urls):
+            if await should_cancel():
+                raise VideoRenderCancelled("视频任务已取消")
+            data, content_type = await _read_image(url)
+            normalized = normalize_image_bytes(data, max_bytes=settings.image_download_max_bytes)
+            suffix = image_extension(normalized.data, content_type or normalized.content_type)
+            image_path = workdir / f"input-{index}{suffix}"
+            image_path.write_bytes(normalized.data)
+            inputs.append(image_path)
+
+        output_path = workdir / "result.mp4"
+        args = [settings.video_ffmpeg_path, "-y", "-hide_banner", "-loglevel", "error"]
+        for image_path in inputs:
+            args.extend(["-loop", "1", "-framerate", str(settings.video_fps), "-t", str(seconds), "-i", str(image_path)])
+
+        filters: list[str] = []
+        for index in range(count):
+            filters.append(
+                f"[{index}:v]scale={settings.video_width}:{settings.video_height}:"
+                "force_original_aspect_ratio=decrease,"
+                f"pad={settings.video_width}:{settings.video_height}:(ow-iw)/2:(oh-ih):color=white,"
+                "setsar=1,format=yuv420p"
+                f"[slide{index}]"
+            )
+        previous = "slide0"
+        accumulated = seconds
+        for index in range(1, count):
+            output = f"fade{index}"
+            filters.append(
+                f"[{previous}][slide{index}]xfade=transition=fade:duration={transition}:"
+                f"offset={accumulated - transition:.3f}[{output}]"
+            )
+            previous = output
+            accumulated += seconds - transition
+        filters.append(f"[{previous}]fps={settings.video_fps},format=yuv420p[video]")
+        args.extend([
+            "-filter_complex", ";".join(filters), "-map", "[video]",
+            "-an", "-c:v", "libx264", "-profile:v", "high", "-pix_fmt", "yuv420p",
+            "-preset", "medium", "-crf", str(settings.video_crf),
+            "-maxrate", settings.video_max_rate, "-bufsize", settings.video_buffer_size,
+            "-movflags", "+faststart", str(output_path),
+        ])
+        await _run_process(args, should_cancel=should_cancel, timeout_seconds=settings.video_render_timeout_seconds)
+        if not output_path.is_file():
+            raise VideoRenderError("FFmpeg 未生成视频文件")
+        file_size = output_path.stat().st_size
+        if file_size > settings.video_max_bytes:
+            raise ResourceSizeLimitError(settings.video_max_bytes, file_size)
+        probe = await _probe(output_path)
+        stream = next((item for item in probe.get("streams", []) if item.get("codec_name") == "h264"), None)
+        if stream is None:
+            raise VideoRenderError("输出视频不是 H.264 编码")
+        width, height = int(stream.get("width", 0)), int(stream.get("height", 0))
+        duration = float((probe.get("format") or {}).get("duration", 0))
+        if (width, height) != (settings.video_width, settings.video_height):
+            raise VideoRenderError(f"输出分辨率异常：{width} × {height}")
+        if not 0 < duration <= settings.video_max_duration_seconds:
+            raise VideoRenderError(f"输出视频时长异常：{duration:.1f} 秒")
+        data = output_path.read_bytes()
+        if len(data) != file_size:
+            raise VideoRenderError("读取视频输出失败")
+        return RenderedVideo(data=data, duration_seconds=duration, width=width, height=height)