January 2011 - ffmpeg-user - lists.ffmpeg.org

Audio channel mapping from ac3 to aac
by news＠achim-hofmann.com 29 Apr '11

29 Apr '11

Hi folks, I'm trying to encode an ac3 audio source file with 6 channels (surround51) into an equivalent aac audio file using this command line: ffmpeg -i test.ac3 -acodec libfaac -ac 6 -ar 48000 -ab 448k test.m4a Unfortunately the channel mapping gets completely disordered. The channel mapping of the so encoded aac audio file looks like this: FL => FR FR => C SL => LFE SR => SL C => FL LFE => SR What do I have to keep the channel mapping used in the source ac3 audio file in the encoded aac audio file? I think I'll have to use one or both of these AVCodecContext AVOptions: -channel_layout <int64> ED.A. -request_channel_layout <int64> .D.A. But I don't have any idea how to use them to get my desired result. Any help would be appreciated. Regards Achim Hofmann

4 3

m2ts to DNxHD convert
by luismanolo＠gmail.com 24 Apr '11

24 Apr '11

Hello. Sorry about my english. I`m a new user of ffmpeg, and I have a sony hd camera. And I want to convert the MTS files of my camera to the codec of Apple Pro Res called dnxhd. I know that this codecs are supported for ffmpeg but I don`t know command to convert the video. I`m a ubuntu linux user. And I use cinelerra to edit the files. Many Thanks. -- http://vimeo.com/luismanolo http://delasonsierra.blogspot.com http://www.logrobomberos.com

6 5

MJPG: Estimating duration from bitrate, this may be inaccurate
by kazakevichilya＠gmail.com 23 Feb '11

23 Feb '11

Hello. While saving mjpg from real-time IP cam I got: [mjpeg @ 01cfd4e0] max_analyze_duration reached [mjpeg @ 01cfd4e0] Estimating duration from bitrate, this may be inaccurate I do not want ffmpeg to estimate anything: I'll stop it using Q when I need. And I really hate that delay before start. So, I did -analyzeduration 0 Delay almost disapppeared, but message still appears. How do I get rid of this message? Can I pass duration from command line? Ilya.

3 2

convert flv to vob
by waldbauernbub＠gmx.at 20 Feb '11

20 Feb '11

Hi, I want to convert a recorder flv-video to a vob-video. I am not very familiar with flv and vob files, yet. But I promised a friend to help him with this christmas present. I am looking for a conversion which leaves as many settings/codecs/bitrate as possible unchanged. The conversion should not create additional artefacts. I studied the man pages of ffmpeg a little bit and came up with this command. But I think this command can be improved, any ffmpeg-expert willing to help? I am still unsure about how to specify the bitrate.. ffmpeg -i test.flv -s 720x404 -target dvd -ar 44100 -aspect 4:3 test.mpg Below is the output of rtmpdump (which I used to record the video stream INFO: duration 3113.03 INFO: moovPosition 32.00 INFO: audiocodecid mp4a INFO: width 720.00 INFO: height 540.00 INFO: videocodecid avc1 INFO: avcprofile 77.00 INFO: avclevel 30.00 INFO: aacaot 2.00 INFO: audiosamplerate 44100.00 INFO: audiochannels 2.00 INFO: videoframerate 25.00 INFO: trackinfo: INFO: length 137284608.00 INFO: timescale 44100.00 INFO: language eng INFO: sampledescription: INFO: sampletype mp4a INFO: length 77813000.00 INFO: timescale 25000.00 INFO: language eng INFO: sampledescription: INFO: sampletype avc1 INFO: length 137288704.00 INFO: timescale 44100.00 INFO: language und INFO: sampledescription: INFO: length 280126800.00 INFO: timescale 90000.00 INFO: language und more info on the input flv-file (output of ffmpeg): Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 25.00 (25/1) Input #0, flv, from 'test.flv': Duration: 01:18:18.55, start: 0.000000, bitrate: N/A Stream #0.0: Video: h264, yuv420p, 720x404 [PAR 1:1 DAR 180:101], 25 tbr, 1k tbn, 50 tbc Stream #0.1: Audio: aac, 44100 Hz, stereo, s16 Thanks for any help. Franz

3 3

How to shift entire frame up or down by 1 pixel?
by dev＠rarevision.com 04 Feb '11

04 Feb '11

Is there a way I can use a -vf option to shift the entire frame up or down by one pixel? I have some interlaced material that VLC will not deinterlace correctly because it seems to expect the field order to be top field first. Unfortunately, this is with container formats that don't have any way of flagging the frame TFF. I've tried the crop and pad options, but they seem to only work with values that are a multiple of two.

5 10

852x480 vs 854x480
by d.reade＠ReadesGroupServices.com 02 Feb '11

02 Feb '11

I have a video recorded at 1920x1080. I want to change the resolution to 480p, but I've read the X should be 853.333 pixels. FFMPEG uses 852 when I specify "hd480" but if I open Fireworks and create a canvas of 1920x1080 then change the resolution (keeping the constraints) to 480 high, the X value is 854. In FFMPEG if I try to use 852x480, the aspect ratio of the output video is "PAR 1:1, DAR 71:40". However using 854x480 the aspect is "PAR 1:1 DAR 427:240". So which resolution should I be using or doesn't it matter?

4 3

Calculate output bitrate to have the same quality as input
by leo.izen＠gmail.com 31 Jan '11

31 Jan '11

Is there an option to automatically calculate the correct bitrate of the output video codec to have the same quality as the input video?

4 8

MKV tags ...
by jahugo＠jacqueshugo.com 31 Jan '11

31 Jan '11

2 2

convert a sequence of images to a video file
by philip＠turmel.org 31 Jan '11

31 Jan '11

[Top-posting repaired. Please don't do that on this list.] On 01/31/2011 10:07 AM, Andrew Jones wrote: > On 31 Jan 2011 22:00, "Phil Turmel" <philip at turmel.org> wrote: [cut] >> Yes, and here's a couple things to try: >> >> ffmpeg -f image2 -r 06 -i %d.JPG output.mp4 >> >> I moved the -r, so it applies to you input images, and dropped the sameq > for test purposes. You can play with quality or bit-rate settings after you > get some output. >> >> If the above doesn't work, try renaming your input files to three digits > (001.JPG, 002.JPG ...) and use this: >> >> ffmpeg -f image2 -r 06 -i %03d.JPG output.mp4 > Tried both methods doesn't work > Is that %03d > Jpg or %o3d.jpg? The o threw a could not find codec error. Digit, not the letter. Please cut-n-paste the complete console output of the above commands so we can see what's going on. Phil

1 0

Converting WPV2 wmv TO FLV
by tankchintan＠gmail.com 31 Jan '11

31 Jan '11

Guys, I am trying to convert a WPV2 file, generated by Windows Photostory to .flv. But I am getting errors when attempting it. Here is the pastebin for it http://ffmpeg.pastebin.com/Dnm3yHPY On IRC I was informed that currently there are no open source decoders for WPV2, if so, is there a fix for this going to be made available soon-ish OR is there any other alternative for resolving? Thanks!

3 3