The components needing delayed frames (sc_screen and sc_v4l2_sink)
managed a sc_video_buffer instance, which itself embedded a
sc_frame_buffer instance (to keep only the most recent frame).
In theory, these components should not be aware of delaying: they should
just receive AVFrames later, and only handle a sc_frame_buffer.
Therefore, refactor sc_delay_buffer as a frame source (it consumes)
frames) and a frame sink (it produces frames, after some delay), and
plug an instance in the pipeline only when a delay is requested.
This also removes the need for a specific sc_video_buffer.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
There was a frame sink trait, implemented by components able to receive
AVFrames, but each frame source had to manually send frame to sinks.
In order to mutualise sink management, add a frame sink trait.
There was a packet sink trait, implemented by components able to
receive AVPackets, but each packet source had to manually send packets
to sinks.
In order to mutualise sink management, add a packet source trait.
A video buffer had 2 responsibilities:
- handle the frame delaying mechanism (queuing packets and pushing them
after the expected delay);
- keep only the most recent frame (using a sc_frame_buffer).
In order to be able to reuse only the frame delaying mechanism, extract
it to a separate component, sc_delay_buffer.
The video_buffer thread clears the queue once it is stopped, but new
frames might still be pushed asynchronously.
To avoid the problem, do not push any frame once the video_buffer is
stopped.
The packets queued for buffering were wrapped in a dynamically allocated
structure with a "next" field.
To avoid this additional layer of allocation and indirection, use a
VecDeque.
The packets queued for recording were wrapped in a dynamically allocated
structure with a "next" field.
To avoid this additional layer of allocation and indirection, use a
VecDeque.
Since in scrcpy a video packet passed to avcodec_send_packet() is always
a complete video frame, it is sufficient to call avcodec_receive_frame()
exactly once.
In practice, it also works for audio packets: the decoder produces
exactly 1 frame for 1 input packet.
In theory, it is an implementation detail though, so
avcodec_receive_frame() should be called in a loop.
By default, scrcpy mirrors only the video when audio capture fails on
the device. Add an option to force scrcpy to fail if audio is enabled
but does not work.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
If there is exactly one producer, then it can assume that the remaining
space in the buffer will only increase until it writes something.
This assumption may allow the producer to write to the buffer (up to a
known safe size) without any synchronization mechanism, thus allowing
to read and write different parts of the buffer in parallel.
The producer can then commit the write with a lock held, and update its
knowledge of the safe empty remaining space.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
When audio capture fails on the device, scrcpy continues mirroring the
video stream. This allows to enable audio by default only when
supported.
However, if an audio configuration occurs (for example the user
explicitly selected an unknown audio encoder), this must be treated as
an error and scrcpy must exit.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
If no bit-rate is passed, let the server use the default value (8Mbps).
This avoids to define a default value on both sides, and to pass the
default bit-rate as an argument when starting the server.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
By default, audio is enabled (--no-audio must be explicitly passed to
disable it).
However, some devices may not support audio capture (typically devices
below Android 11, or Android 11 when the shell application is not
foreground on start).
In that case, make the server notify the client to dynamically disable
audio forwarding so that it does not wait indefinitely for an audio
stream.
Also disable audio on unknown codec or missing decoder on the
client-side, for the same reasons.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
For video streams (at least H.264 and H.265), the config packet
containing SPS/PPS must be prepended to the next packet (the following
keyframe).
For audio streams (at least OPUS), they must not be merged.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
The client does not use the audio stream if there is no display and no
recording (i.e. only V4L2), so disable audio so that the device does not
attempt to capture it.
PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>
