Michael Rampe
Forum Replies Created
-
[Ankuj Gupta] “I am trying to decode a H263 4CIF(704×576) resolution file with ffmpeg, but it is detected as mp3 file and fails to get decoded. I tried with lower resolution H263 files they get decoded easily. I am using ffmpeg version 0.6.1”
I created a file to replicate your issue and it decoded properly:
Stream #0.0(eng): Video: h263, yuv420p, 704×576 [PAR 12:11 DAR 4:3], 780 kb/s, 25 fps, 25 tbr, 25 tbn, 29.97 tbc
Can you give me some more information. What container are you using, framerate and can you post the ffmpeg command line and output?
Michael
-
[Alex Pavlov] “Thank you Michael. But what if I set maxrate = 2000K instead of 9000K?
And then calculate total size like
sz:=((VideoBitrate/1000)/8)*totalsec+((AudioBitrate/1000)/8)*totalsec;
(where VideoBitrate = 2000K and AudioBitrate=448000. totalsec is a length of the movie). What do you think?”2000k seems a bit low. do some tests to find a good quality/size setting.
Also, maxrate requires bufsize to be set.
not sure of your equation. video bitrate is in Kbits, audio bitrate is only in bits in your example (assuming 48000 instead of 448000) Do you want the output in Megabytes? If so with video at 2000K and audio at 48K I guess it would read ((2000+48)/1024/8)*totalsec
Michael
-
you will find the x264 presets in the ffpresets folder. Try some different ones and then limit to main profile as a second vpre option.
eg “-vpre fast -vpre main”
Michael
-
Try using the -b bitrate setting on two pass encoding. This will produce a file very close to the specified bitrate. For dvd you may need to use -maxrate, -minrate and -bufsize as well to ensure the stream is compliant.
Michael
-
[Guillermo Carrion] “Could that command be optimized for better results?”
Most definitely. Which version of FFmpeg and Wowza are you using for this project? seems quite old due to lack of a -vpre for x264. Funnily enough, I am also currently doing work on getting wowza to stream to iphones and other mobile devices.
Anyway, I think you could achieve much better quality using a main profile, higher bitrate and larger size.
Michael
-
The distribution should be in /opt/local/var/macports/distfiles/ffmpeg/
You can build that yourself.
Why not just grab the latest git repository without macports?
Michael
-
[derek winnicki] “I installed FFMpeg successfully with this method but Im trying to compile a program that needs libavformat, do you know which directory macports puts in?”
For me it goes to:
/opt/local/var/macports/software/ffmpeg/….Michael
-
[Joseph Thompson] “I’ve been to that site numerous times but it does not explain how to create your own presets. I tried using Notepad and when I called it from FFMpeg it errored out, “invalid characters””
Is notepad writing rich text instead of plain text?
I use simpletext on the Mac (sometimes) and you have to force it to plain text for it to work.
Michael
-
[Joseph Thompson] ” Can I create presets using notepad and saving it with a .ffpreset extension?”
Check this:
https://www.ffmpeg.org/ffmpeg.html#SEC13
It is well documented. Have a look at one of the existing ones for an example.
Which library/codec are you intending this for?
Michael
-
Not sure about Visualhub but take a look at iFFmpeg on OSX. Looks promising….
Michael