Expose `OutputContainer._started`?

[oakaigh]

Currently it's impossible to determine if encoding has started on an arbitrary container. Exposing the _started property should make it possible.

[WyattBlue]

Check the size of the bytes/file?

[oakaigh]

Check the size of the bytes/file?

That's one way to do it; not trivial to implement though (since you need to get the underlying io, which pyav does not expose).

[WyattBlue]

It is very trivial to get the size:

import av
import io
import numpy as np

b = io.BytesIO()
c = av.open(b, "w", format="wav")

stream = c.add_stream("pcm_s16le", rate=44100, layout="mono")

samples = np.array([[100, 200, 300, 400]], dtype=np.int16)

print(f"Size: {b.getbuffer().nbytes} bytes") # 0 bytes

frame = av.AudioFrame.from_ndarray(samples, format="s16", layout="mono")
frame.sample_rate = 44100
frame.pts = 0

for packet in stream.encode(frame):
    c.mux(packet)
for packet in stream.encode(None):   # flush encoder
    c.mux(packet)

c.close()

print(f"Size: {b.getbuffer().nbytes} bytes")  # 86 bytes

[oakaigh]

I do not have control over the lifecycle of containers; Containers must be passed externally to my helper function.

[WyattBlue]

I do not have control over the lifecycle of containers;

I recommend not doing that, although if you really need it, I welcome you to make a PR.