I know I can play audio with MediaElement on wp7/8.
I'm looking for a way to grab audio samples.
By audio samples I mean decoded samples not the raw mp3 stream for example.
How can I do that ?
The short answer is no.
The longer answer is that would of course be possible if you implemented an audio decoder (e.g. MP3) as part of your app.
Related
I'm trying to make sense of something YouTube has listed on their recommended upload encoding settings for the best possible quality. Here's the link: https://support.google.com/youtube/answer/1722171#zippy=%2Caudio-codec-aac-lc
Specifically this line:
Channels: Stereo or Stereo + 5.1
I'm Googling for "Stereo + 5.1" and anything to do with ffmpeg but I can't seem to find much of anything.
I have trailers with surround audio I need to export for a client for YouTube.
You need to create a stereo downmix. (5.1 to stereo).
See https://trac.ffmpeg.org/wiki/AudioChannelManipulation#a5.1stereo
Then you combine your
video
audio (stereo) and
audio (5.1)
into one file with a total of 3 tracks.
We have a DirectShow application where we capture video input from USB, multiplex with audio from a WAV file (backing music), overlay audio and video effects, compress and write to an MP4 file.
Originally we were using an audio input source (microphone) and mixing our backing music and sound effects over the top but the decision was made to not capture live audio, and so I thought it would make more sense to use the backing music WAV file itself as the audio source.
Here is the filter graph we have:
backing.wav is a simple WAV file (stored locally), and was added to the graph using IFilterGraph::AddSourceFilter.
The problem is that when the graph is run, no audio samples are delivered from the WAV file. The video part of the graph runs as normal, but it's as if the audio part of the graph simply isn't running.
If I stop the graph in GraphEdit, add the Default DirectSound Device audio renderer and hook that up in place of the AAC Encoder filter and then run the graph again, the audio plays as you would expect.
Additionally, if backing.wav is replaced with an audio capture source like a microphone, audio data flows through as normal.
Does anyone have any ideas why the above graph, using a WAV file as the audio source, would fail to produce any audio samples?
I suppose the title is incorrectly identifying/summarizing the problem. There is nothing to tell for the fact that audio is not produced. It is likely that it is produced equally well with DirectSound Renderer and with AAC Encoder, specifically the data is reaching output pin of Mixing Transform Filter (is this your filter? You should be able to trace its flow and see media samples passing though).
With the information given, I would say it's likely that custom AAC encoder somehow does not like the feed and somehow either drops data or switches to erroneous state. You should be able to debug this further by inserting a Sample Grabber (or alike) filter¹ before the AAC encoder and tracing the media samples. Also comparing them to data from another source. The encoder might be sensitive to small details like media sample duration or discontinuity flag on the first sample streamed.
¹ With GraphStudioNext (GraphEdit makes no longer sense compared to) you can use internal Analyzer Filter and review media sample flow interactively using filter property page.
I have to record videos for a project I'm doing. Two of these are USB cameras and another is a n IP overhead camera.All three are connected to a laptop computer. After recording the videos I need to be able to open them in an editor (not for editing particularly but for modeling stuff in them for which I need a timeline). I have chosen Sony Vegas Pro for my editor. I have been able to record the uncompressed avi using gstreamer with this command:
gst-launch v4l2src device=/dev/video0 ! 'video/x-rawyuv,width=640,height=480,framerate=10/1' ! mux. avimux name=mux ! filesink location=temp.avi
I had to set the framerate to 10 because I was using two USB cameras and a framerate of 30 on both could not be accomodated in the bandwidth of the USB controller. I do not care about audio in my file so I don't grab audio. Similary, while encoding I wouldn't care about audio as well. This is raw uncompressed avi. I was not able to open this in Sony Vegas Pro. I believe I need to encode this uncompressed avi using a codec that will be opened by Sony Vegas Pro (I don't know which codecs Sony likes, so I'll probably try different ones until one of them opens).
For encoding this video, I have several options: mencoder, ffmpeg, gstreamer. But I am not able to figure out how to use these tools to get what I want. Ideally, I would like just to sort of "insert" a codec with other settings remaining the same. I don't really care about the how much space the resulting video takes since the length of the videos are not going to be more than 3 minutes and I have space available, so lossless codecs also work. I believe Sony reads mpeg avi's so if I can get that, it'll be great.
Thanks for reading and I appreciate all the help.
I was able to figure this out after some searching. It is based on the information here. I found that Sony Vegas pro seems to open avi videos encoded with the xvid codec.
I've been writing an audio conversion application in OSX meant for use in podcasting, and I've run into an issue. I can access the QTTrack for the audio I want, but it has two very different audio channels on the left speaker and on the right speaker. Is there any way I can create two new audio files and/or play them inside the program - one for the sounds coming from the left speaker, and one for the sounds coming from the right speaker, separately from each other?
I am looking for some sites where I can download some short clips (5-20seconds) for testing purposes of video import routines.
Does anyone has some data sources for wmv, mpeg, mov, etc. ?
Thanks!
http://www.open-video.org/
http://www.archive.org/
http://reefvid.org/
Or just take some short vids with a digital video camera (or digital camera), import them onto your computer.
You can convert video files at http://www.zamzar.com/ to any format from any format.
Youtube, and convert it with ffmpeg
Or film trailers are often in mov (imdb: http://www.imdb.com/Sections/Trailers/ )
Or game trailers, gamershell / gamespot / ...
I was searching for this few days ago and here is best one I found:
http://www.jhepple.com/support/sample_movies1.htm
16 different files (two original samples), rather small sizes, covering most of popular formats.
MetaCafe allows you to download videos. I have some clips that I use for testing which are downloaded from there.
Some HD clips:
http://www.microsoft.com/windows/windowsmedia/musicandvideo/hdvideo/contentshowcase.aspx - Windows Media Audio and Video 9 Series, 1080p WMV files
http://www.apple.com/quicktime/guide/hd/ - H.264 in Quicktime containers
http://www.w6rz.net/ MPEG-2 Transport Stream Test Patterns