def cache_inner(fn, *args, **kwargs):
cache_prefix = kwargs.pop('cache_prefix', None)
cache_path = cache_path_for_file_path(fn, cache_prefix)
if cache_path and os.path.exists(cache_path):
with open(cache_path, "rb") as cache_file:
cache_value = pickle.load(cache_file)
else:
cache_value = func(fn, *args, **kwargs)
if cache_path:
with atomic_write_in_dir(cache_path, mode="wb", overwrite=True) as cache_file:
pickle.dump(cache_value, cache_file, -1)
return cache_value
def index_pstream(fns, typ, cache_prefix=None):
if typ != "h264":
raise NotImplementedError(typ)
if not fns:
raise DataUnreadableError("chffr h264 requires contiguous files")
out_fns = [cache_path_for_file_path(fn, cache_prefix) for fn in fns]
out_exists = map(os.path.exists, out_fns)
if all(out_exists): return
# load existing index files to avoid re-doing work
existing_indexes = []
for out_fn, exists in zip(out_fns, out_exists):
existing = None
if exists:
with open(out_fn, "rb") as cache_file:
existing = pickle.load(cache_file)
existing_indexes.append(existing)
# probe the first file
if existing_indexes[0]:
probe = existing_indexes[0]['probe']
else:
with FileReader(fns[0]) as f:
probe = ffprobe(f.name, typ)
global_prefix = None
# get the video index of all the segments in this stream
indexes = []
for i, fn in enumerate(fns):
if existing_indexes[i]:
index = existing_indexes[i]['index']
prefix = existing_indexes[i]['global_prefix']
else:
with FileReader(fn) as f:
index, prefix = vidindex(f.name, typ)
if i == 0:
# assert prefix
if not prefix:
raise DataUnreadableError("vidindex failed for %s" % fn)
global_prefix = prefix
indexes.append(index)
assert global_prefix
if np.sum(indexes[0][:, 0] == H264_SLICE_I) <= 1:
print(
"pstream %s is unseekable. pre-decompressing all the segments..." %
(fns[0]))
pstream_predecompress(fns, probe, indexes, global_prefix, cache_prefix)
return
# generate what's required to make each segment self-contained
# (the partial GOP from the end of each segments are put asside to add
# to the start of the following segment)
prefix_data = ["" for _ in fns]
prefix_index = [[] for _ in fns]
for i in xrange(len(fns) - 1):
if indexes[i + 1][0, 0] == H264_SLICE_I and indexes[i + 1][0, 1] <= 1:
# next file happens to start with a i-frame, dont need use this file's end
continue
index = indexes[i]
if i == 0 and np.sum(index[:, 0] == H264_SLICE_I) <= 1:
raise NotImplementedError("No I-frames in pstream.")
# find the last GOP in the index
frame_b = len(index) - 1
while frame_b > 0 and index[frame_b, 0] != H264_SLICE_I:
frame_b -= 1
assert frame_b >= 0
assert index[frame_b, 0] == H264_SLICE_I
end_len = len(index) - frame_b
with FileReader(fns[i]) as vid:
vid.seek(index[frame_b, 1])
end_data = vid.read()
prefix_data[i + 1] = end_data
prefix_index[i + 1] = index[frame_b:-1]
# indexes[i] = index[:frame_b]
for i, fn in enumerate(fns):
cache_path = out_fns[i]
if os.path.exists(cache_path):
continue
segment_index = {
'index': indexes[i],
'global_prefix': global_prefix,
'probe': probe,
'prefix_frame_data':
prefix_data[i], # data to prefix the first GOP with
'num_prefix_frames':
len(prefix_index[i]), # number of frames to skip in the first GOP
}
with atomic_write_in_dir(cache_path, mode="wb",
overwrite=True) as cache_file:
pickle.dump(segment_index, cache_file, -1)
def pstream_predecompress(fns,
probe,
indexes,
global_prefix,
cache_prefix,
multithreaded=False):
assert len(fns) == len(indexes)
out_fns = [
cache_path_for_file_path(fn, cache_prefix, extension=".predecom.mkv")
for fn in fns
]
out_exists = map(os.path.exists, out_fns)
if all(out_exists):
return
w = probe['streams'][0]['width']
h = probe['streams'][0]['height']
frame_size = w * h * 3 / 2 # yuv420p
decompress_proc = subprocess.Popen([
"ffmpeg", "-threads", "0" if multithreaded else "1", "-vsync", "0",
"-f", "h264", "-i", "pipe:0", "-threads",
"0" if multithreaded else "1", "-f", "rawvideo", "-pix_fmt", "yuv420p",
"pipe:1"
],
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=open("/dev/null", "wb"))
def write_thread():
for fn in fns:
with FileReader(fn) as f:
decompress_proc.stdin.write(f.read())
decompress_proc.stdin.close()
def read_frame():
frame = None
try:
frame = decompress_proc.stdout.read(frame_size)
except (IOError, ValueError):
pass
if frame is None or frame == "" or len(frame) != frame_size:
raise DataUnreadableError("pre-decompression failed for %s" % fn)
return frame
t = threading.Thread(target=write_thread)
t.daemon = True
t.start()
try:
for fn, out_fn, out_exist, index in zip(fns, out_fns, out_exists,
indexes):
if out_exist:
for fi in xrange(index.shape[0] - 1):
read_frame()
continue
with atomic_write_in_dir(out_fn, mode="w+b",
overwrite=True) as out_tmp:
compress_proc = subprocess.Popen([
"ffmpeg", "-threads", "0" if multithreaded else "1", "-y",
"-vsync", "0", "-f", "rawvideo", "-pix_fmt", "yuv420p",
"-s",
"%dx%d" % (w, h), "-i", "pipe:0", "-threads",
"0" if multithreaded else "1", "-f", "matroska", "-vcodec",
"ffv1", "-g", "0", out_tmp.name
],
stdin=subprocess.PIPE,
stderr=open(
"/dev/null", "wb"))
try:
for fi in xrange(index.shape[0] - 1):
frame = read_frame()
compress_proc.stdin.write(frame)
compress_proc.stdin.close()
except:
compress_proc.kill()
raise
assert compress_proc.wait() == 0
cache_path = cache_path_for_file_path(fn, cache_prefix)
with atomic_write_in_dir(cache_path, mode="wb",
overwrite=True) as cache_file:
pickle.dump(
{
'predecom': os.path.basename(out_fn),
'index': index,
'probe': probe,
'global_prefix': global_prefix,
}, cache_file, -1)
except:
decompress_proc.kill()
raise
finally:
t.join()
rc = decompress_proc.wait()
if rc != 0:
raise DataUnreadableError(fns[0])