# 本文公开核验脚本：仅验证随附原创文件及声明的有限条件。
import json, csv, hashlib, re, struct, subprocess, sys, zlib
from fractions import Fraction
from pathlib import Path
P = Path(__file__).resolve().parent
def read(name): return json.loads((P/name).read_text(encoding='utf-8-sig'))
def digest(name): return hashlib.sha256((P/name).read_bytes()).hexdigest()
def probe(name, *args):
    command = ['ffprobe','-v','error',*args,'-of','json',str(P/name)]
    run = subprocess.run(command,capture_output=True,text=True,encoding='utf-8',timeout=25)
    assert run.returncode == 0, run.stderr
    return json.loads(run.stdout)
def decode(name):
    command=['ffmpeg','-v','error','-xerror','-i',str(P/name),'-map','0:v?','-map','0:a?','-f','null','-']
    run=subprocess.run(command,capture_output=True,text=True,encoding='utf-8',timeout=25)
    assert run.returncode == 0, run.stderr
    assert not run.stderr.strip(), run.stderr
    return {'file':name,'exit_code':run.returncode,'stderr':run.stderr}
def packets(name, select='v:0'):
    return probe(name,'-select_streams',select,'-show_packets')['packets']
def streams(name): return probe(name,'-show_streams','-show_format')
def stamp(v,base): return Fraction(int(v))*Fraction(base)
def framehash(name):
    run=subprocess.run(['ffmpeg','-v','error','-i',str(P/name),'-map','0:V:0','-f','framemd5','-'],capture_output=True,text=True,encoding='utf-8',timeout=25)
    assert run.returncode==0,run.stderr
    return [x.split(',')[-1].strip() for x in run.stdout.splitlines() if x and not x.startswith('#')]
def emit(value): print(json.dumps(value,ensure_ascii=False,indent=2))

result={}
for f in ['source.mp4','copy-cut.mp4','exact-cut.mp4']:
 x=packets(f);result[f]={'first_packet_pts':x[0]['pts_time'],'first_packet_dts':x[0]['dts_time'],'packet_count':len(x),'frame_count':len(framehash(f)),'decode':decode(f)}
assert Fraction(result['copy-cut.mp4']['first_packet_pts'])<0;assert result['exact-cut.mp4']['frame_count']==10
emit({'files':result,'note':'流复制副本含目标点前包；首个显示帧另受容器edit list和播放器处理影响。'})