I want to play an MP4 file showing a reaching task for an experiment. I am not sure how to formulate the syntax. So far I have:
moviefile = 'GOPR0056.MP4';
screenNum = 0;
[window, rect] = Screen('OpenWindow', screenNum, 1);
moviePtr = Screen('OpenMovie', window, moviefile);
Screen('PlayMovie', moviePtr, 1);
But I'm getting an issue:
PTB-ERROR: Could not open movie file [GOPR0056.MP4] for playback! No such moviefile with the given path and filename.
PTB-ERROR: The specific file URI of the missing movie was: file:///GOPR0056.MP4.
The file is located in the directory. May I be getting a video drivers error because this is a MP4 file. Thanks.
When playing videos with Psychtoolbox, always provide the full path, even if the video is in the current directory. Try this:
moviefile = [pwd filesep 'GOPR0056.MP4'];
Related
I'm editing all frames of an existing mp4 video in MATLAB (doing it in a for loop).
After I'm done editing, I want to save the new set of frames to a new output video file, but in mp4 rather than .avi (that seems to be the default).
I thought changing the filename extension is sufficient, but apparently it's not.
Any ideas?
newVid = VideoWriter(outputfilename);
newVid.FrameRate = fps;
newVid.Quality = 100;
open(newVid)
for...
writeVideo(newVid,imgs{i})%within the for loop saving one frame at a time
end
close(newVid)
Renaming the file is not sufficient. You also need to specify the codec you want. In your case, you need to include an additional parameter into the VideoWriter constructor that consists of the codec you want to use as a MATLAB
string. In your case, specify 'MPEG-4':
newVid = VideoWriter(outputfilename, 'MPEG-4'); % New
newVid.FrameRate = fps;
newVid.Quality = 100;
open(newVid);
for ...
% Rest of your code here
BTW, have a look at the documentation in the future. It clearly shows you what to do if you want to save to a new format, and not AVI: https://www.mathworks.com/help/matlab/ref/videowriter.html#input_argument_d0e1094625
You need to pass a profile argument to matlab's videowriter.
From Matlab Help, VideoWriter(filename,profile) creates a VideoWriter object and applies a set of properties tailored to a specific file format (such as 'MPEG-4' or 'Uncompressed AVI').
In your case, you need to pass the string MPEG-4 to the profile argument.
I have a weird problem... I want to create a video with the extension .tif with a lot of frames. My script is running well 2 times over 3 but it crashes randomly sometimes...
I have a loop which has the length of the total of frames in the video and at each turn I add a tif to my multipage tif.
There is my code to create the new video :
% --- Create the new frame
newVid.cData = iL(y0:y0end, x0:x0end);
% --- Create the new video
if nbrFrames == 1
imwrite(newVid.cData,dataOutVid);
else
imwrite(newVid.cData,dataOutVid,'WriteMode','append');
end
Each turn I change the value of "newVid.cData". in fact the new video is a portion of an original video in which I focused on a specific object (a mouse for me). "dataOutVid" is the path where I store the new video and the extension of the path is .tif.
How I obtain the path:
disp('Where do you want to save the new video and under which name ?');
[name, path] = uiputfile({'.tif'}, 'Save Video');
dataOutVid = strcat(path,name);
There is the mistake I can possibly have randomly:
Error using imwrite (line 454)
Unable to open file "D:\Matlab\Traitement Vidéo\test.tif" for writing. You might not have write permission.
Error in mouseExtraction(line 164)
imwrite(newVid.cData,dataOutVid,'WriteMode','append');
Well I don't understand why this error appears randomly (one time at the frame 270, another time at the frame 1250, etc...). How is it possible I suddendly loose the right to overwrite my file...
Edit : I already checked if I didn't have a RAM problem but I only use 20% of it during the execution of the script...
I'm trying to play an http live stream to iphone, it looks like i have looked every example, mistakes and everything that i could found on the internet and apple docs about http live stream, and i think i'm in a dead end now.. I'm using MPMoviePlayer as in most of examples. Also i have to add the i can see the stream if i open the url from vlc player.
I succeeded in playing the apple BipBop stream on my iPhone that is here but can't play my stream. I figured that my url shows not in the m3u8 file so i found this terminal command, and successfully used it.
/Applications/VLC.app/Contents/MacOS/VLC --intf=rc rtp://#239.35.86.11:10000
'--sout=#transcode{fps=25,vcodec=h264,venc=x264{aud,profile=baseline,level=30, keyint=30,bframes=0,ref=1,nocabac},acodec=mp3,ab=56,audio-sync,deinterlace}:standard{mux=ts,dst=-,access=file}' | mediastreamsegmenter -b http://192.168.1.16/~Jonas/streaming/ -f
/users/jonas/sites/streaming/ -D
Now i have a playlist m3u8 file locally on my machine. As i understand with the command i download stream divide it into smaller ts files and generate m3u8 file that is like a reference to those ts files. So i've tried to load this, but still no luck. For some reasons i can't even open the m3u8 file in vlc or itunes, it throws me errors. So i guess it is something wrong with the playlist file?
Maybe some of you can see what am i doing wrong here or have some suggestions how to find my problem? I would really appreciate it.
It looks like your iOS code is just fine and that it is your server-side code that is causing issues, primarily with regards to generating the m3u8 playlist and possibly with how you're hosting the ts files that it references.
Unfortunately my example code is a bit noisy as I wrote it a year ago (it is in python) and it does a bit more than you're asking for (it live-transcodes a video into the correct m3u8/ts stuff) but it is tested and functional.
You can take a look at the code here: https://github.com/DFTi/ScribbeoServer/blob/python/transcode.py
I will paste some of the relevant methods here for your convenience; I hope it helps you:
def start_transcoding(self, videoPath):
if DISABLE_LIVE_TRANSCODE:
print "Live transcoding is currently disabled! There is a problem with your configuration."
return
print "Initiating transcode for asset at path: "+videoPath
videoPath = unquote(videoPath)
video_md5 = md5.new(videoPath).hexdigest()
if self.sessions.has_key(video_md5): # Session already exists?
return self.m3u8_bitrates_for(video_md5)
transcodingSession = TranscodeSession(self, videoPath)
if transcodingSession.can_be_decoded():
self.sessions[transcodingSession.md5] = transcodingSession
return self.m3u8_bitrates_for(transcodingSession.md5)
else:
return "Cannot decode this file."
def m3u8_segments_for(self, md5_hash, video_bitrate):
segment = string.Template("#EXTINF:$length,\n$md5hash-$bitrate-$segment.ts\n")
partCount = math.floor(self.sessions[md5_hash].duration / 10)
m3u8_segment_file = "#EXTM3U\n#EXT-X-TARGETDURATION:10\n"
for i in range(0, int(partCount)):
m3u8_segment_file += segment.substitute(length=10, md5hash=md5_hash, bitrate=video_bitrate, segment=i)
last_segment_length = math.ceil((self.sessions[md5_hash].duration - (partCount * 10)))
m3u8_segment_file += segment.substitute(length=last_segment_length, md5hash=md5_hash, bitrate=video_bitrate, segment=i)
m3u8_segment_file += "#EXT-X-ENDLIST"
return m3u8_segment_file
def m3u8_bitrates_for(self, md5_hash):
m3u8_fudge = string.Template(
"#EXTM3U\n"
# "#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=384000\n"
# "$hash-384-segments.m3u8\n"
# "#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=512000\n"
# "$hash-512-segments.m3u8\n"
"#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=768000\n"
"$hash-768-segments.m3u8\n"
# "#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1024000\n"
# "$hash-1024-segments.m3u8\n"
)
return m3u8_fudge.substitute(hash=md5_hash)
def segment_path(self, md5_hash, the_bitrate, segment_number):
# A segment was requested.
path = self.sessions[md5_hash].transcode(segment_number, the_bitrate)
if path:
return path
else:
raise "Segment path not found"
That project is all open source now and can be found here: https://github.com/DFTi/ScribbeoServer/tree/python
Binaries can be found here: http://scribbeo.com/server
Good luck!
I am having a problem when creating an avi file using Matlab. My aim is to use an edge filter on an entire video and save the file as an avi. The filter works fine, my problem is the writing of the avi file.
My code:
vidFile = VideoReader('video.avi');
edgeMov = avifile('edges','fps',30);
for i = 1:vidFile.numberofframes
frameI = read(vidFile,i);
frameIgray = rgb2gray(frameI);
edgeI = edge(frameIgray,'canny',0.6);
edgeIuint8 = im2uint8(edgeI);
edgeIuint8(:,:,2) = edgeIuint8(:,:,1);
edgeIuint8(:,:,3) = edgeIuint8(:,:,1);
edgeMov = addframe(edgeMov,edgeIuint8);
end
edgeMov = close(edgeMov)
When the loop finishes and the avifile is closed, I go to play the video and it says "Windows Media Player encountered a problem while playing this file". I've also tried, without success, Media Player Classic and VLC which lead me to believe that the problem must be the file itself. Using GSpot I checked the file and it said that the AVI header is corrupt.
Retrying the loop again returned exactly the same problem. What's confusing me is when I run the loop for a smaller number of frames, 30 for example, the video writes fine and I can watch it. The size of the video I am trying to convert is in excess of 1000 frames so I don't know if size is a problem?
Any help would be greatly appreciated, thank you.
I've used the following to create AVI
edgeMov = avifile('video.avi','compression','Indeo5','fps',15,'quality',95);
Give it a try.
No matter what I try (build -> content, NSUrl, filename) I get a 'null exception': file not found when I try to play a .caf sound file in monotouch.
//var path = NSBundle.MainBundle.PathForResource("MatchGame", "caf");
//var gameSong = SystemSound.FromFile( new NSUrl(path, false));
var gameSong = SystemSound.FromFile("MatchGame.caf");
gameSong.PlaySystemSound();
I also try combinations using the folder name "images/MatchGame.caf" and moving MatchGame.caf into the root folder.
What am I missing? Thanks a lot.
Here is a link to a video of adding the sound in monotouch. http://www.screencast.com/t/MmE0ZmFh What is wrong?
Bryan,
From looking at your screencast - you are trying to play a mp3 file and not a caf file. Mp3 files are encoded differently and will not play with the SystemSound class that's there (I can't remember if you can do this in Obj-C or not.)
You'll want to use the AVFoundation Namespace and AVAudioPlayer class.
using Monotouch.AVFoundation;
var mediaFile = NSUrl.FromFilename("myMp3.mp3");
var audioPlayer = AVAudioPlayer.FromUrl(mediaFile);
audioPlayer.FinishedPlaying += delegate { audioPlayer.Dispose(); };
audioPlayer.Play();
You might need to tweak the code above - I don't have MonoDevelop to hand but that should help you a little further.
Cheers,
ChrisNTR
You need the first line:
var path = NSBundle.MainBundle.PathForResource("MatchGame", "caf");
Then make sure that your audio file is included in the application by making sure that your CAF file is flagged as "Content" in the Properties pane, otherwise the file is not copied to the resulting application package (your .app)
You can follow the steps documented here (they are for images, but apply the same to audio files):
http://wiki.monotouch.net/HowTo/Images/Add_an_Image_to_your_Project
Additionally, this is a good resource for where you should store files:
http://wiki.monotouch.net/HowTo/Files/HowTo%3a_Store_Files