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demuxer fails when corrupted PES packet advertises incorrect length #35

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tmm1 opened this issue Jan 21, 2022 · 2 comments
Open

demuxer fails when corrupted PES packet advertises incorrect length #35

tmm1 opened this issue Jan 21, 2022 · 2 comments

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@tmm1
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tmm1 commented Jan 21, 2022

I have a sample that looks like this:

$ ./astits-probe packets -i id3.ts
2022/01/21 12:07:04 Fetching packets...
2022/01/21 12:07:04 PKT: 0
2022/01/21 12:07:04   Continuity Counter: 4
2022/01/21 12:07:04   Payload Unit Start Indicator: true
2022/01/21 12:07:04   Has Payload: true
2022/01/21 12:07:04   Has Adaptation Field: false
2022/01/21 12:07:04   Transport Error Indicator: false
2022/01/21 12:07:04   Transport Priority: false
2022/01/21 12:07:04   Transport Scrambling Control: 0
2022/01/21 12:07:04 PKT: 480
2022/01/21 12:07:04   Continuity Counter: 4
2022/01/21 12:07:04   Payload Unit Start Indicator: true
2022/01/21 12:07:04   Has Payload: true
2022/01/21 12:07:04   Has Adaptation Field: false
2022/01/21 12:07:04   Transport Error Indicator: false
2022/01/21 12:07:04   Transport Priority: false
2022/01/21 12:07:04   Transport Scrambling Control: 0
2022/01/21 12:07:04 PKT: 502
2022/01/21 12:07:04   Continuity Counter: 13
2022/01/21 12:07:04   Payload Unit Start Indicator: true
2022/01/21 12:07:04   Has Payload: true
2022/01/21 12:07:04   Has Adaptation Field: false
2022/01/21 12:07:04   Transport Error Indicator: false
2022/01/21 12:07:04   Transport Priority: false
2022/01/21 12:07:04   Transport Scrambling Control: 0
2022/01/21 12:07:04 PKT: 502
2022/01/21 12:07:04   Continuity Counter: 14
2022/01/21 12:07:04   Payload Unit Start Indicator: true
2022/01/21 12:07:04   Has Payload: true
2022/01/21 12:07:04   Has Adaptation Field: true
2022/01/21 12:07:04   Transport Error Indicator: false
2022/01/21 12:07:04   Transport Priority: false
2022/01/21 12:07:04   Transport Scrambling Control: 0
2022/01/21 12:07:04   Adaptation Field: &{AdaptationExtensionField:<nil> DiscontinuityIndicator:false ElementaryStreamPriorityIndicator:false HasAdaptationExtensionField:false HasOPCR:false HasPCR:false HasTransportPrivateData:false HasSplicingCountdown:false Length:80 IsOneByteStuffing:false StuffingLength:79 OPCR:<nil> PCR:<nil> RandomAccessIndicator:false SpliceCountdown:0 TransportPrivateDataLength:0 TransportPrivateData:[]}
2022/01/21 12:07:04 PKT: 502
2022/01/21 12:07:04   Continuity Counter: 15
2022/01/21 12:07:04   Payload Unit Start Indicator: false
2022/01/21 12:07:04   Has Payload: true
2022/01/21 12:07:04   Has Adaptation Field: true
2022/01/21 12:07:04   Transport Error Indicator: false
2022/01/21 12:07:04   Transport Priority: false
2022/01/21 12:07:04   Transport Scrambling Control: 0
2022/01/21 12:07:04   Adaptation Field: &{AdaptationExtensionField:<nil> DiscontinuityIndicator:false ElementaryStreamPriorityIndicator:false HasAdaptationExtensionField:false HasOPCR:false HasPCR:false HasTransportPrivateData:false HasSplicingCountdown:false Length:82 IsOneByteStuffing:false StuffingLength:81 OPCR:<nil> PCR:<nil> RandomAccessIndicator:false SpliceCountdown:0 TransportPrivateDataLength:0 TransportPrivateData:[]}

which fails to demux with this error:

$ ./astits-probe data -i id3.ts
2022/01/21 12:09:22 Fetching data...
2022/01/21 12:09:22 astits: fetching data failed: astits: getting next data failed: astits: building new data failed: astits: parsing PES data failed: astits: fetching next bytes failed: astikit: slice length is 184, offset 285 is invalid

http://0x0.st/oo1F.bin
@tmm1
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tmm1 commented Jan 21, 2022

I ran the same sample through ffmpeg, and noticed:

[mpegts @ 0x7fd14b815000] PES packet size mismatch
[mpegts @ 0x7fd14b815000] Packet corrupt (stream = 3, dts = 466149000).

Then I tried DVBInspector, and it appears the first packet advertises a length of 279 bytes, but the rest of the data never appears.

Screen Shot 2022-01-21 at 12 34 17 PM

Ideally astits would detect and ignore this corruption.

@tmm1 tmm1 changed the title demuxer fails on metadata PES split across two packets demuxer fails when corrupted PES packet advertises incorrect length Jan 21, 2022
@tmm1
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tmm1 commented Jan 21, 2022

Ideally astits would detect and ignore this corruption.

If we implemented the CorruptedPacketHandler described in #22 (comment), these packets could be sent there instead of being silently ignored.

@tmm1 tmm1 mentioned this issue Jan 21, 2022
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