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FFMPEG tweaks (#321)
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* ffmpeg: allow more control over ffmpeg params (#294)

* Refactor ffmpeg info parsing a bit, so we can test it easier

* fixes for getting ffmpeg fps

* ffmpeg: new fps param for reading, to overload files fps
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@almarklein
almarklein committed Mar 13, 2018
1 parent a22145a commit 1d4e4fc
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Showing 4 changed files with 306 additions and 133 deletions.
219 changes: 135 additions & 84 deletions imageio/plugins/ffmpeg.py
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Expand Up @@ -174,6 +174,11 @@ class FfmpegFormat(Format):
Parameters for reading
----------------------
fps : scalar
The number of frames per second to read the data at. Default None (i.e.
read at the file's own fps). One can use this for files with a
variable fps, or in cases where imageio is unable to correctly detect
the fps.
loop : bool
If True, the video will rewind as soon as a frame is requested
beyond the last frame. Otherwise, IndexError is raised. Default False.
Expand All @@ -187,10 +192,14 @@ class FfmpegFormat(Format):
"gray"). The camera needs to support the format in order for
this to take effect. Note that the images produced by this
reader are always rgb8.
ffmpeg_params: list
input_params : list
List additional arguments to ffmpeg for input file options.
(Can also be provided as ``ffmpeg_params`` for backwards compatibility)
Example ffmpeg arguments to use aggressive error handling:
['-err_detect', 'aggressive']
output_params : list
List additional arguments to ffmpeg for output file options (i.e. the
stream being read by imageio).
print_info : bool
Print information about the video file as reported by ffmpeg.
Expand All @@ -205,7 +214,7 @@ class FfmpegFormat(Format):
quality : float | None
Video output quality. Default is 5. Uses variable bit rate. Highest
quality is 10, lowest is 0. Set to None to prevent variable bitrate
flags to FFMPEG so you can manually specify them using ffmpeg_params
flags to FFMPEG so you can manually specify them using output_params
instead. Specifying a fixed bitrate using 'bitrate' disables this
parameter.
bitrate : int | None
Expand All @@ -217,8 +226,12 @@ class FfmpegFormat(Format):
pixelformat: str
The output video pixel format. Default is 'yuv420p' which most widely
supported by video players.
ffmpeg_params: list
input_params : list
List additional arguments to ffmpeg for input file options (i.e. the
stream that imageio provides).
output_params : list
List additional arguments to ffmpeg for output file options.
(Can also be provided as ``ffmpeg_params`` for backwards compatibility)
Example ffmpeg arguments to use only intra frames and set aspect ratio:
['-intra', '-aspect', '16:9']
ffmpeg_log_level: str
Expand Down Expand Up @@ -285,7 +298,7 @@ def _get_cam_inputname(self, index):
infos = proc.stderr.read().decode('utf-8')
# Return device name at index
try:
name = self._parse_device_names(infos)[index]
name = parse_device_names(infos)[index]
except IndexError:
raise IndexError('No ffdshow camera at index %i.' % index)
return 'video=%s' % name
Expand All @@ -299,26 +312,9 @@ def _get_cam_inputname(self, index):
else: # pragma: no cover
return '??'

@staticmethod
def _parse_device_names(ffmpeg_output):
""" Parse the output of the ffmpeg -list-devices command"""
device_names = []
in_video_devices = False
for line in ffmpeg_output.splitlines():
if line.startswith('[dshow'):
logging.debug(line)
line = line.split(']', 1)[1].strip()
if in_video_devices and line.startswith('"'):
device_names.append(line[1:-1])
elif 'video devices' in line:
in_video_devices = True
elif 'devices' in line:
# set False for subsequent "devices" sections
in_video_devices = False
return device_names

def _open(self, loop=False, size=None, pixelformat=None,
ffmpeg_params=None, print_info=False):
print_info=False, ffmpeg_params=None,
input_params=None, output_params=None, fps=None):
# Get exe
self._exe = self._get_exe()
# Process input args
Expand All @@ -336,7 +332,9 @@ def _open(self, loop=False, size=None, pixelformat=None,
elif not isinstance(pixelformat, string_types):
raise ValueError('FFMPEG pixelformat must be str')
self._arg_pixelformat = pixelformat
self._arg_ffmpeg_params = ffmpeg_params if ffmpeg_params else []
self._arg_input_params = input_params or []
self._arg_output_params = output_params or []
self._arg_input_params += ffmpeg_params or [] # backward compat
# Write "_video"_arg
self.request._video = None
if self.request.filename in ['<video%i>' % i for i in range(10)]:
Expand Down Expand Up @@ -418,9 +416,13 @@ def _initialize(self):
'-pix_fmt', self._pix_fmt,
'-vcodec', 'rawvideo']
oargs.extend(['-s', self._arg_size] if self._arg_size else [])
if self.request.kwargs.get('fps', None):
fps = float(self.request.kwargs['fps'])
oargs += ['-r', "%.02f" % fps]
# Create process
cmd = [self._exe] + self._arg_ffmpeg_params
cmd += iargs + ['-i', self._filename] + oargs + ['-']
cmd = [self._exe] + self._arg_input_params
cmd += iargs + ['-i', self._filename]
cmd += oargs + self._arg_output_params + ['-']
# For Windows, set `shell=True` in sp.Popen to prevent popup
# of a command line window in frozen applications.
self._proc = sp.Popen(cmd, stdin=sp.PIPE,
Expand All @@ -447,19 +449,21 @@ def _reinitialize(self, index=0):
# Also appears this epsilon below is needed to ensure frame
# accurate seeking in some cases
epsilon = -1/self._meta['fps']*0.1
iargs = ['-ss', "%.06f" % (starttime+epsilon),
'-i', self._filename,
]
iargs = ['-ss', "%.06f" % (starttime+epsilon)]
iargs += ['-i', self._filename]

# Output args, for writing to pipe
oargs = ['-f', 'image2pipe',
'-pix_fmt', self._pix_fmt,
'-vcodec', 'rawvideo']
oargs.extend(['-s', self._arg_size] if self._arg_size else [])

if self.request.kwargs.get('fps', None):
fps = float(self.request.kwargs['fps'])
oargs += ['-r', "%.02f" % fps]

# Create process
cmd = [self._exe] + self._arg_ffmpeg_params
cmd += iargs + oargs + ['-']
cmd = [self._exe] + self._arg_input_params + iargs
cmd += oargs + self._arg_output_params + ['-']
# For Windows, set `shell=True` in sp.Popen to prevent popup
# of a command line window in frozen applications.
self._proc = sp.Popen(cmd, stdin=sp.PIPE,
Expand All @@ -481,7 +485,7 @@ def _terminate(self):
# Using kill since self._proc.terminate() does not seem
# to work for ffmpeg, leaves processes hanging
self._proc.kill()

# Tell threads to stop when they have a chance. They are probably
# blocked on reading from their file, but let's play it safe.
if self._stderr_catcher:
Expand Down Expand Up @@ -528,51 +532,20 @@ def _load_infos(self):
raise IOError("Could not open steam %s." % self._filename)
else: # pragma: no cover - this is checked by Request
raise IOError("%s not found! Wrong path?" % self._filename)

# Get version
ver = lines[0].split('version', 1)[-1].split('Copyright')[0]
self._meta['ffmpeg_version'] = ver.strip() + ' ' + lines[1].strip()

# get the output line that speaks about video
videolines = [l for l in lines if l.lstrip().startswith('Stream ')
and ' Video: ' in l]
line = videolines[0]

# get the frame rate
matches = re.findall(" ([0-9]+\.?[0-9]*) (tbr|fps)", line)
fps = 0
if matches: # Can be empty, see #171, assume nframes = inf
fps = float(matches[0][0].strip())
self._meta['fps'] = fps

# get the size of the original stream, of the form 460x320 (w x h)
match = re.search(" [0-9]*x[0-9]*(,| )", line)
parts = line[match.start():match.end()-1].split('x')
self._meta['source_size'] = tuple(map(int, parts))

# get the size of what we receive, of the form 460x320 (w x h)
line = videolines[-1] # Pipe output
match = re.search(" [0-9]*x[0-9]*(,| )", line)
parts = line[match.start():match.end()-1].split('x')
self._meta['size'] = tuple(map(int, parts))

# Check the two sizes
if self._meta['source_size'] != self._meta['size']:
logging.warning('Warning: the frame size for reading %s is '
'different from the source frame size %s.' %
(self._meta['size'],
self._meta['source_size']))

# get duration (in seconds)
line = [l for l in lines if 'Duration: ' in l][0]
match = re.search(" [0-9][0-9]:[0-9][0-9]:[0-9][0-9].[0-9][0-9]",
line)
if match is not None:
hms = map(float, line[match.start()+1:match.end()].split(':'))
self._meta['duration'] = duration = cvsecs(*hms)
if fps:
self._meta['nframes'] = int(round(duration*fps))

# Go!
self._meta.update(parse_ffmpeg_info(lines))

# Update with fps with user-value?
if self.request.kwargs.get('fps', None):
self._meta['fps'] = float(self.request.kwargs['fps'])

# Estimate nframes
self._meta['nframes'] = np.inf
if self._meta['fps'] > 0 and 'duration' in self._meta:
n = int(round(self._meta['duration'] * self._meta['fps']))
self._meta['nframes'] = n

def _read_frame_data(self):
# Init and check
w, h = self._meta['size']
Expand Down Expand Up @@ -632,6 +605,7 @@ def _get_exe(cls):

def _open(self, fps=10, codec='libx264', bitrate=None,
pixelformat='yuv420p', ffmpeg_params=None,
input_params=None, output_params=None,
ffmpeg_log_level="quiet", quality=5,
macro_block_size=16):
self._exe = self._get_exe()
Expand Down Expand Up @@ -714,7 +688,9 @@ def _initialize(self):
quality = self.request.kwargs.get('quality', 5)
ffmpeg_log_level = self.request.kwargs.get('ffmpeg_log_level',
'warning')
extra_ffmpeg_params = self.request.kwargs.get('ffmpeg_params', [])
input_params = self.request.kwargs.get('input_params') or []
output_params = self.request.kwargs.get('output_params') or []
output_params += self.request.kwargs.get('ffmpeg_params') or []
# You may need to use -pix_fmt yuv420p for your output to work in
# QuickTime and most other players. These players only supports
# the YUV planar color space with 4:2:0 chroma subsampling for
Expand All @@ -730,11 +706,12 @@ def _initialize(self):
"-vcodec", "rawvideo",
'-s', sizestr,
'-pix_fmt', self._pix_fmt,
'-r', "%.02f" % fps,
'-i', '-', '-an',
'-vcodec', codec,
'-pix_fmt', pixelformat,
]
'-r', "%.02f" % fps] + input_params
cmd += ['-i', '-']
cmd += ['-an',
'-vcodec', codec,
'-pix_fmt', pixelformat,
]
# Add fixed bitrate or variable bitrate compression flags
if bitrate is not None:
cmd += ['-b:v', str(bitrate)]
Expand Down Expand Up @@ -789,7 +766,7 @@ def _initialize(self):
# output from ffmpeg by default. That way if there are warnings
# the user will see them.
cmd += ['-v', ffmpeg_log_level]
cmd += extra_ffmpeg_params
cmd += output_params
cmd.append(self._filename)
self._cmd = " ".join(cmd) # For showing command if needed
if any([level in ffmpeg_log_level for level in
Expand Down Expand Up @@ -956,6 +933,80 @@ def run(self):
self._lines = limit_lines_local(self._lines)


def parse_device_names(ffmpeg_output):
""" Parse the output of the ffmpeg -list-devices command"""
device_names = []
in_video_devices = False
for line in ffmpeg_output.splitlines():
if line.startswith('[dshow'):
logging.debug(line)
line = line.split(']', 1)[1].strip()
if in_video_devices and line.startswith('"'):
device_names.append(line[1:-1])
elif 'video devices' in line:
in_video_devices = True
elif 'devices' in line:
# set False for subsequent "devices" sections
in_video_devices = False
return device_names


def parse_ffmpeg_info(text):
meta = {}

if isinstance(text, list):
lines = text
else:
lines = text.splitlines()

# Get version
ver = lines[0].split('version', 1)[-1].split('Copyright')[0]
meta['ffmpeg_version'] = ver.strip() + ' ' + lines[1].strip()

# get the output line that speaks about video
videolines = [l for l in lines if l.lstrip().startswith('Stream ')
and ' Video: ' in l]
line = videolines[0]

# get the frame rate.
# matches can be empty, see #171, assume nframes = inf
# the regexp omits values of "1k tbr" which seems a specific edge-case #262
# it seems that tbr is generally to be preferred #262
matches = re.findall(" ([0-9]+\.?[0-9]*) (tbr|fps)", line)
fps = 0
matches.sort(key=lambda x: x[1] == 'tbr', reverse=True)
if matches:
fps = float(matches[0][0].strip())
meta['fps'] = fps

# get the size of the original stream, of the form 460x320 (w x h)
match = re.search(" [0-9]*x[0-9]*(,| )", line)
parts = line[match.start():match.end()-1].split('x')
meta['source_size'] = tuple(map(int, parts))

# get the size of what we receive, of the form 460x320 (w x h)
line = videolines[-1] # Pipe output
match = re.search(" [0-9]*x[0-9]*(,| )", line)
parts = line[match.start():match.end()-1].split('x')
meta['size'] = tuple(map(int, parts))

# Check the two sizes
if meta['source_size'] != meta['size']:
logging.warning('Warning: the frame size for reading %s is '
'different from the source frame size %s.' %
(meta['size'], meta['source_size']))

# get duration (in seconds)
line = [l for l in lines if 'Duration: ' in l][0]
match = re.search(" [0-9][0-9]:[0-9][0-9]:[0-9][0-9].[0-9][0-9]",
line)
if match is not None:
hms = map(float, line[match.start()+1:match.end()].split(':'))
meta['duration'] = cvsecs(*hms)

return meta


def get_output_video_line(lines):
"""Get the line that defines the video stream that ffmpeg outputs,
and which we read.
Expand Down
6 changes: 6 additions & 0 deletions tests/test_dicom.py
View file
Expand Up @@ -58,6 +58,12 @@ def test_read_empty_dir():
assert imageio.formats.search_read_format(request) is None


def test_dcmtk():
# This should not crach, we make no assumptions on whether its
# available or not
imageio.plugins.dicom.get_dcmdjpeg_exe()


def test_selection():

dname1, dname2, fname1, fname2 = _prepare()
Expand Down

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