68 lines
2.3 KiB
Python
68 lines
2.3 KiB
Python
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import sys,time,struct,os
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BODY=bytes([6,14,43,52,2,5,1,1,13,1,2,1,1,3])
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ITS=bytes([6,14,43,52,2,83,1,1,13,1,2,1,1,16,1,0])
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def get_frames(p):
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try:
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sz=os.path.getsize(p)
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if sz<50000:return 0
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with open(p,"rb") as f:
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f.seek(max(0,sz-3000000));d=f.read()
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pos=len(d)
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while True:
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i=d.rfind(BODY,0,pos)
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if i<0:break
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pos=i;bs=i+16;b0=d[bs]
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if b0==0x83:bl,bv=4,struct.unpack(">I",b"\x00"+d[bs+1:bs+4])[0]
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elif b0==0x82:bl,bv=3,struct.unpack(">H",d[bs+1:bs+3])[0]
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else:bl,bv=1,b0
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if len(d)<bs+bl+48:break
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ibc=struct.unpack(">Q",d[bs+bl+40:bs+bl+48])[0]
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if not ibc:continue
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itd=d[i+16+bl+bv:i+16+bl+bv+ibc]
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ii=itd.find(ITS)
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if ii<0:break
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ib0=itd[ii+16]
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if ib0==0x83:ivl,ivv=4,struct.unpack(">I",b"\x00"+itd[ii+17:ii+20])[0]
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elif ib0==0x82:ivl,ivv=3,struct.unpack(">H",itd[ii+17:ii+19])[0]
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else:ivl,ivv=1,ib0
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sd=itd[ii+16+ivl:ii+16+ivl+ivv];p2=isp=dur=0
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while p2<len(sd)-3:
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t=struct.unpack(">H",sd[p2:p2+2])[0];l=struct.unpack(">H",sd[p2+2:p2+4])[0]
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if p2+4+l>len(sd):break
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v=sd[p2+4:p2+4+l]
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if t==0x3F0C and l==8:isp=struct.unpack(">q",v)[0]
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elif t==0x3F0D and l==8:dur=struct.unpack(">q",v)[0]
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p2+=4+l
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return max(0,isp+dur)
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except:return 0
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return 0
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mxf=sys.argv[1]
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while not os.path.exists(mxf) or os.path.getsize(mxf)<20000:time.sleep(0.3)
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with open(mxf,"rb") as f:hdr=f.read(200000)
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offs=[]
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for pat in [b"\x02\x02\x00\x08\xff\xff\xff\xff\xff\xff\xff\xff",b"\x30\x02\x00\x08\xff\xff\xff\xff\xff\xff\xff\xff"]:
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p=0
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while True:
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i=hdr.find(pat,p)
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if i<0:break
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offs.append(i+4);p=i+1
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print("[dur-patch] %d Duration fields"%len(offs),flush=True)
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def patch(val):
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if not offs:return
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try:
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with open(mxf,"r+b") as f:
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for o in offs:f.seek(o);f.write(struct.pack(">q",val))
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except Exception as e:print("[dur-patch] err:",e,flush=True)
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# Premiere rejects a growing OP1a/RDD9 whose header Duration is -1 on import
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# (bmx thread 87ac5750: Premiere prefers 0). raw2bmx writes -1 at clip-open, so
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# overwrite every -1 with 0 immediately, BEFORE any frames exist, then track the
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# live frame count every 3s.
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patch(0)
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print("[dur-patch] Duration=0 (initial)",flush=True)
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while True:
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time.sleep(3)
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fc=get_frames(mxf)
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if fc>0:
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patch(fc)
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print("[dur-patch] Duration=%d"%fc,flush=True)
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