# If we want to access frame at index 10, frame = vr[9] print(frame.shape) ################################################################ # For deep learning, usually we want to get multiple frames at once. Now you can use ``get_batch`` function, # Suppose we want to get a 32-frame video clip by skipping one frame in between, frame_id_list = range(0, 64, 2) frames = vr.get_batch(frame_id_list).asnumpy() print(frames.shape) ################################################################ # There is another advanced functionality, you can get all the key frames as below, key_indices = vr.get_key_indices() key_frames = vr.get_batch(key_indices) print(key_frames.shape) ################################################################ # Pretty flexible, right? Try it on your videos. ################################################################ # Speed comparison # ---------------- ################################################################ # Now we want to compare its speed with Opencv VideoCapture to demonstrate its efficiency. # Let's load the same video and get all the frames randomly using both decoders to compare their performance. # We will run the loading for 11 times: use the first one as warming up, and average the rest 10 runs as the average speed.
def video_legal(video_path, remove_illegal=True):
# 检查切出来的视频是否可读
try:
cv_wrong = False
cap = cv2.VideoCapture(str(video_path))
flag, f = cap.read()
if not flag:
cv_wrong = True
cap.release()
if cv_wrong:
# opencv检测出视频不正常，删掉
print("opencv remove", video_path, flush=True)
if remove_illegal:
os.remove(str(video_path))
return False
vr = VideoReader(str(video_path))
last_timestamp = [-100, -100]
video_wrong = False if (len(vr) > 1
and len(vr.get_key_indices()) > 1) else True
if video_wrong:
print("len vr {} and len(vr.get_key_indices()) {}".format(
len(vr), len(vr.get_key_indices())),
video_path,
flush=True)
if remove_illegal:
os.remove(str(video_path))
return False
for i in range(len(vr)):
# 解决卡住
tmp = vr.get_frame_timestamp(i)
if last_timestamp[0] == tmp[0] and last_timestamp[1] <= tmp[1]:
print("last_timestamp",
i,
video_path,
last_timestamp[0],
tmp[0],
last_timestamp[1],
tmp[1],
flush=True)
video_wrong = True
break
last_timestamp = tmp
if video_wrong:
print("timestamp error", video_path, flush=True)
if remove_illegal:
os.remove(str(video_path))
return False
for i in range(len(vr)):
# 解决decord._ffi.base.DECORDError: [18:09:55] /io/decord/src/video/ffmpeg -loglevel quiet/threaded_decoder.cc:288: [18:08:29] /io/decord/src/video/ffmpeg -loglevel quiet/threaded_decoder.cc:216: Check failed: avcodec_send_packet(dec_ctx_.get(), pkt.get()) >= 0 (-1094995529 vs. 0) Thread worker: Error sending packet.
try:
_t = vr[i]
except Exception as e:
print("DECORDError", e, i, video_path, flush=True)
if remove_illegal:
os.remove(str(video_path))
return False
except:
print("remove video format exception", video_path, flush=True)
if remove_illegal:
os.remove(str(video_path))
return False
return True
