I’m building a project for streaming audio/video from a network webcam. I’ve successfully managed to get h264 stream data after modifying the built in Transport. I believe my next goal is to set it up to be a a Membrane Source, but i can’t find any existing documentation in the hexdocs for this. Ha…

Hi @ConnorRigby , you’re totally right - source is the way to pass the stream into a Membrane pipeline. The docs you’re looking for are here: Membrane.Source . As described there, sources should implement Membrane.Element.Base and Membrane.Element.WithOutputPads behaviours. Various source implementati…

There’s no straightforward way to ‘skip stages’ in membrane. Imho the best option would be to make disector send SPS/PPS via notification to the pipeline, store them in the state and pass to the decoder via options upon spawning . It would require the decoder to support passing SPS/PPS via options, b…

Thanks. I’ll try that out. I hacked some things together and i ran into a different error, but let me try building it out the “correct” way first.

@mat-hek should should pix_fmt be automatically detected somehow? i’ve tried sending the SPS and PPS values to the decoder before the frames come in, but i’m still getting a send_pkt error. Update: i’ve managed to get by the send_pkt error, but it looks like my camera’s pixel format is unsupported…

another update: Finally got some video from the camera with some modifications to the ffmpeg element. I’m still getting tons of: [h264 @ 0x7f2f5c02e080] non-existing PPS 0 referenced even though i’ve sent (what i believe to be) the pps frame. The video renders and runs smooth, but that message is…

Just jumping in to say I’m really enjoying the thread and even more the tenacity by both of your to get this thing going!

That error may be printed out by the h264 parser, that is also based on FFmpeg (pure elixir implementation in progress). This can be fixed by passing parameter sets to the parser instead of the decoder.

Tried that and it at least changed the messages. [h264 @ 0x7f78d002a7c0] Frame num change from 0 to 1 [h264 @ 0x7f78d002a7c0] decode_slice_header error [h264 @ 0x7f78d002a7c0] error while decoding MB 15 1, bytestream -20 [h264 @ 0x7f78d002a7c0] concealing 8074 DC, 8074 AC, 8074 MV errors in P frame…

Are you sure that parameter sets are still passed to the decoder also?

yes they are passed to both in the same order, sps first, pps second. The decoder will error and fail completely if i don’t send both sps and pps. The parser seems to be okay without either, but sends that non-existing PPS 0 referenced error on every frame. Adding the sps and pps to the parser resu…

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ConnorRigby January 28, 2020, 4:33pm 32

ah i see. I’ll have to add that to another PR