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"""
ffprobe wrapper shared by stream-time codec detection (transport/webrtc_server.py)
and index-time technical-field enrichment (indexer/enrich.py).
Split out of webrtc_server.py so the indexer package (which webrtc_server.py
already imports from) can call it too without a circular import.
"""
import asyncio
import json
_H264_PROFILES = {"Baseline": "42", "Main": "4d", "High": "64", "High 10": "6e"}
# Source video codecs whose MSE codec string is real but which no mainstream
# browser can actually decode via MediaSource on most desktop platforms — HEVC
# has no royalty-free decoder in Chrome/Firefox on Linux (and is spotty even
# on platforms with one). Found live: a real HEVC/EAC3 WEB-DL reported
# "Codec not supported for streaming: hev1.1.6.L93.B0,mp4a.40.2" from
# MediaSource.isTypeSupported, even though ffprobe/VLC play it fine. VP9/AV1
# are not in this set — those decode natively in every mainstream browser.
BROWSER_INCOMPATIBLE_VIDEO_CODECS = frozenset({"hevc"})
async def probe_video(
path: str,
) -> tuple[str | None, float, bool, int | None, int | None, str | None]:
"""
Probe video file with ffprobe, return (MSE codec string, duration,
has_audio, width, height, raw video codec name).
The audio half of the codec string is always "mp4a.40.2" (AAC-LC) or
absent — never the source's real audio codec — because the streaming
path always transcodes audio to AAC and never copies it: MSE in every
mainstream browser only decodes AAC/Opus, and a source codec outside
that (AC-3, E-AC-3, DTS, ...) is at best silently unplayable and at
worst, for E-AC-3 at least, makes ffmpeg itself refuse to write the
fragmented MP4 header ("Cannot write moov atom before EAC3 packets
parsed" — reproduced against a real 5.1 E-AC-3 WEB-DL). Video is copied
whenever the browser can decode it directly; the raw codec name is
returned alongside the MSE string so the caller can decide whether this
source needs a real re-encode instead (BROWSER_INCOMPATIBLE_VIDEO_CODECS
above) — the MSE string alone can't drive that decision, since it still
faithfully reports "hev1..." for a source this pipeline cannot actually
deliver copied.
width/height come from the same ffprobe call (one extra `-show_entries`
field, no second process spawn) — resolution is deliberately never
guessed from the filename (docs/mediacenter.md §3.5).
"""
from meshbay_node.platform import ffprobe_cmd
proc = await asyncio.create_subprocess_exec(
ffprobe_cmd(), "-v", "error",
"-show_entries", "stream=codec_name,profile,level,codec_type,width,height",
"-show_entries", "format=duration",
"-of", "json", path,
stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE,
)
stdout, _ = await proc.communicate()
info = json.loads(stdout)
duration = float(info.get("format", {}).get("duration", 0))
v_codec = ""
raw_codec_name: str | None = None
has_audio = False
width: int | None = None
height: int | None = None
for s in info.get("streams", []):
if s.get("codec_type") == "video" and not v_codec:
cn = s.get("codec_name", "")
raw_codec_name = cn or None
if cn == "h264":
p = _H264_PROFILES.get(s.get("profile", "High"), "64")
lvl = int(s.get("level", 40))
v_codec = f"avc1.{p}00{lvl:02x}"
elif cn == "hevc":
v_codec = "hev1.1.6.L93.B0"
elif cn == "vp9":
v_codec = "vp09.00.10.08"
elif cn == "av1":
v_codec = "av01.0.01M.08"
width = s.get("width")
height = s.get("height")
elif s.get("codec_type") == "audio":
has_audio = True
if not v_codec:
return None, duration, has_audio, width, height, raw_codec_name
codec = f"{v_codec},mp4a.40.2" if has_audio else v_codec
return codec, duration, has_audio, width, height, raw_codec_name
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