Sound and Formats

Sorry if this has already been asked somewhere, but I haven’t been able to find a solution for two days now.

I am trying to get all my movies in AVI Codec, but I want to add audio to the movie as well. I’ve tried following the manuals at but to no avail, my movies are still silent.

And another thing is that the finished product needs to be in .flv format. As far as I know, Blender doesnt support this file type correct? I was just going to use a converter, but I don’t want to risk quality if I dont have too.

Thanks in advance :slight_smile:

#1. I assume that you use 2.5x
#2. audio issue: make sure that you set an audio codec in the encoding panel together with the appropriate sampling and bit rates. Note that none is enabled by default.
#3. flash output: Blender does fully support flv. Choose MPEG as a file format and then choose flash video. If you want more control, render out to a losseless format (e.g. huffy) and then use an external app such as ffmpeg to transcode the video to flv.

Some more info:

AVI is not a codec, but a container format for video and audio streams, both usually compressed by codecs. For codecs you have a number of choices that can be used for video & audio – which to pick often depends on where the final video will end up for viewing, and which codecs you have on your system.

FLV is a proprietary format, Flash video, which is in essence both a video codec and a container format. AFAIK you can’t do FLV into an AVI container.

I’ve had some success using 2.57 (no a or b) to run some tests of the FLV option, both silent and muxed with audio. Using the raw PNG image sequence output for my movie Kata, I’ve been able to produce good-quality FLV-format files with the AAC audio codec that are comparable in size to AVI with Xvid & mp3 compression. Personally I prefer AVI/Xvid’s quality for the video but the FLV is acceptable when that format is required.

The biggest questions regarding using these options are about the settings for bitrate and GOP size, and similar settings for the audio codecs. There are no defaults in Blender except some that are used in the presets, so experimentation is in order.

Just FYI, my FLV test outputs produced the best results with the Kata footage using these specs:

Output – MPEG (required for audio/video multiplexing, aka “muxing,” in Blender)
Encoding – Format: Flash; Bitrate = 3000 ; GOP Size: 18-72 depending on the subject matter – generally, lower numbers = better quality = larger file size; Rate: Min = 0, Max = 9000, Buffer = 1792; Mux: Rate = 1008000, Packet Size = 2048; Audio Codec = AAC; Bitrate = 224, Sample Rate = 48000, Volume = 1.0

I have to admit some of these specs are opaque to me, I basically copied them from one of the presets to start with, but they seem to work OK. My PNG image sequence was loaded into the VSE along with the pre-mixed audio track in WAV format. My image size was only 768 x 432, so the VSE ran it out pretty fast, about 0.15sec/frame for 7160 frames. YMMV.

The .flv movie that resulted played well in VLC, and using an Open Source javascript player I found on the web (JWPlayer), I’ve been able to embed some small silent FLV movies in my recently-updated website (link below if you’re interested – see the Kata & Othello pages). I find this a good alternative to Quicktime, since the only decent video codec for that container is MPEG-4, which as Blender implements it seems to generate a lot of artifacts on playback both in the QT player and via the QT web plug-in.

Mucho gracious senor. I thought I was going to miss my deadline because of this problem but your suggested audio/video settings work perfectly for my needs. Thanks again :slight_smile:

Oh no he hath speaketh the name of the beast! “MUXING” quick everyone run for the hills!!!

Maybe we should start a thread for usefull ffmpeg presets in Blender?
Who will follow me to slay the beast?

"And he came upon a man speaking in tongues as if possessed, and asked ‘What is your name?’ And thus he spake, ‘My name is Jargon, for we are many words and acronyms, and lo, abbreviations also, and confusion incarnate, and we spread uncertainty and discord among the users!’ "
– from The Gospels of Bob, translated from the original Geek

Sure, I think a “Book of the Mux” would be cool.

Yae verily!