def _create_resizer(self, width, height):
self.resizer = ct.POINTER(mmal.MMAL_COMPONENT_T)()
mmal_check(mmal.mmal_component_create(
mmal.MMAL_COMPONENT_DEFAULT_RESIZER, self.resizer),
prefix="Failed to create resizer component")
if not self.resizer[0].input_num:
raise PiCameraError("No input ports on resizer component")
if not self.resizer[0].output_num:
raise PiCameraError("No output ports on resizer component")
# Copy the original input port's format to the resizer's input,
# then the resizer's input format to the output, and configure it
mmal.mmal_format_copy(self.resizer[0].input[0][0].format,
self.input_port[0].format)
mmal_check(mmal.mmal_port_format_commit(self.resizer[0].input[0]),
prefix="Failed to set resizer input port format")
mmal.mmal_format_copy(self.resizer[0].output[0][0].format,
self.resizer[0].input[0][0].format)
fmt = self.resizer[0].output[0][0].format
fmt[0].es[0].video.width = width
fmt[0].es[0].video.height = height
fmt[0].es[0].video.crop.x = 0
fmt[0].es[0].video.crop.y = 0
fmt[0].es[0].video.crop.width = width
fmt[0].es[0].video.crop.height = height
mmal_check(mmal.mmal_port_format_commit(self.resizer[0].output[0]),
prefix="Failed to set resizer output port format")
def _create_encoder(self):
"""
Creates and configures the encoder itself
"""
assert not self.encoder
self.encoder = ct.POINTER(mmal.MMAL_COMPONENT_T)()
mmal_check(mmal.mmal_component_create(self.encoder_type, self.encoder),
prefix="Failed to create encoder component")
if not self.encoder[0].input_num:
raise PiCameraError("No input ports on encoder component")
if not self.encoder[0].output_num:
raise PiCameraError("No output ports on encoder component")
# Ensure output format is the same as the input
self.output_port = self.encoder[0].output[0]
if self.resizer:
mmal.mmal_format_copy(self.encoder[0].input[0][0].format,
self.resizer[0].output[0][0].format)
else:
mmal.mmal_format_copy(self.encoder[0].input[0][0].format,
self.input_port[0].format)
mmal_check(mmal.mmal_port_format_commit(self.encoder[0].input[0]),
prefix="Failed to set encoder input port format")
mmal.mmal_format_copy(self.output_port[0].format,
self.encoder[0].input[0][0].format)
# Set buffer size and number to appropriate values
self.output_port[0].buffer_size = max(
self.output_port[0].buffer_size_recommended,
self.output_port[0].buffer_size_min)
self.output_port[0].buffer_num = max(
self.output_port[0].buffer_num_recommended,
self.output_port[0].buffer_num_min)
def _callback_recycle(self, port, buf):
"""
Recycles the buffer on behalf of the encoder callback function
"""
new_buf = mmal.mmal_queue_get(self.pool[0].queue)
if not new_buf:
raise PiCameraError(
"Unable to get a buffer to return to the encoder port")
mmal_check(mmal.mmal_port_send_buffer(port, new_buf),
prefix="Unable to return a buffer to the encoder port")
def _create_pool(self):
"""
Allocates a pool of buffers for the encoder
"""
assert not self.pool
self.pool = mmal.mmal_port_pool_create(self.output_port,
self.output_port[0].buffer_num,
self.output_port[0].buffer_size)
if not self.pool:
raise PiCameraError(
"Failed to create buffer header pool for encoder component")
def _callback_write(self, buf):
"""
Performs output writing on behalf of the encoder callback function;
return value determines whether writing has completed.
"""
if buf[0].length:
mmal_check(mmal.mmal_buffer_header_mem_lock(buf),
prefix="Unable to lock buffer header memory")
try:
with self.lock:
if self.output:
written = self.output.write(
ct.string_at(buf[0].data, buf[0].length))
# Ignore None return value; most Python 2 streams have
# no return value for write()
if (written
is not None) and (written != buf[0].length):
raise PiCameraError(
"Unable to write buffer to file - aborting")
finally:
mmal.mmal_buffer_header_mem_unlock(buf)
return bool(buf[0].flags & mmal.MMAL_BUFFER_HEADER_FLAG_EOS)
def _callback_write(self, buf):
# Overridden to strip alpha bytes when necessary, and manually
# calculate the frame end
if buf[0].length and self._image_size:
mmal_check(mmal.mmal_buffer_header_mem_lock(buf),
prefix="Unable to lock buffer header memory")
try:
s = ct.string_at(buf[0].data, buf[0].length)
if self._strip_alpha:
s = b''.join(s[i:i + 3] for i in range(0, len(s), 4))
with self.lock:
if self.output:
written = self.output.write(s)
# Ignore None return value; most Python 2 streams have
# no return value for write()
if (written is not None) and (written != len(s)):
raise PiCameraError(
"Unable to write buffer to file - aborting")
self._image_size -= len(s)
assert self._image_size >= 0
finally:
mmal.mmal_buffer_header_mem_unlock(buf)
return self._image_size <= 0
