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scottlamb / retina

High-level RTSP multimedia streaming library, in Rust
https://crates.io/crates/retina
Apache License 2.0
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Add ability to parse Annex B stream in FU-A. #99

Closed thatdevsherry closed 3 months ago

thatdevsherry commented 3 months ago

Summary

Add ability to break apart an Annex B stream sent in a FU-A. Fixes #68. Deleted original branch hence this one is opened up. Original at #71.

Details

My V380 cam would send a FU-A after establishing RTSP connection. The FU-A was not conformant to spec.

FU-A (start) => [ sps header - sps - boundary - pps header - pps - boundary - idr header - idr ] # Annex B stream
FU-A (...) => [ sps header - idr ]
FU-A (end) => [ sps header - idr ]

Notice how all the frags have the same header (as they should be), but the start has an Annex B stream, meaning the last NAL picked from that packet is an IDR. This means the last NAL saved from first packet will be an IDR, but the next fragment will have... the header for SPS, but data for IDR, which is wrong.

It appears that the camera only does this for FU-A that has SPS & PPS. FU-As & single NAL units for other NAL types are conformant to spec.

I have only modified this logic for the FU-A flow. We can however use the start_rtp_nal, append_rtp_nal and end_rtp_nal to handle all NAL types.

Camera details

Name: V380 (It's a generic V380 outdoor camera) Firmware: HwV380E31_WF8_PTZ_WIFI_20201218 (I had asked them for a firmware update file to enable RTSP support)

thatdevsherry commented 3 months ago

Better to have context in a single PR, sorry for spam.