Posted by admin on January 21, 2015 under Tech Tips | 
Here’s a quick tip on using Mencoder profiles that serve as shortcuts for all of your favorite settings. This can save you a lot of time, especially when your encoding syntax is lengthy and difficult to remember.
Profiles are stored in the mencoder.conf file located in the appropriate place for your operating system. For Linux users, you can create a personalized file in your own home directory, ~/.mplayer/mencoder.conf.
Here’s the syntax you might use on a single-pass XviD project without using profiles.
mencoder -oac mp3lame -lameopts aq=0:q=0 -ovc xvid -xvidencopts
fixed_quant=2:max_key_interval=25:vhq=2:bvhq=1:chroma_opt:quant_type=mpeg
input.avi -o output.avi
Compare that with the following examples of some of my favorite profiles, and how easy it is to use them.
XviD Single-pass Profile Example
[xvid]
profile-desc="MPEG4/MP3 encoding"
ovc=xvid=1
xvidencopts=fixed_quant=2:max_key_interval=25:vhq=2:bvhq=1:chroma_opt=1:quant_type=mpeg
oac=mp3lame=1
lameopts=aq=0:q=0
mencoder -profile xvid input.avi -o output.avi
XviD 2-pass Profile Examples
[xvid-pass1]
profile-desc="MPEG4/MP3 encoding - PASS 1"
ovc=xvid=1
xvidencopts=pass=1:max_key_interval=25:turbo=1:vhq=0
nosound=1
o=/dev/null
passlogfile=xvid-pass1.log
[xvid-pass2]
profile-desc="MPEG4/MP3 encoding - PASS 2"
ovc=xvid=1
xvidencopts=pass=2:max_key_interval=25:vhq=2:bvhq=1:chroma_opt=1:quant_type=mpeg:bitrate=2000
oac=mp3lame=1
lameopts=aq=0:q=0
passlogfile=xvid-pass1.log
mencoder -profile xvid-pass1 input.avi
mencoder -profile xvid-pass2 input.avi -o output.avi
x264 2-pass Profile Examples
[x264-pass1]
profile-desc="x264 encoding - PASS 1"
ovc=x264=1
x264encopts=pass=1:threads=0:subq=1:frameref=1:bframes=3:b_pyramid=normal:weight_b=1:keyint=25
nosound=1
o=/dev/null
passlogfile=x264-pass1.log
[x264-pass2]
profile-desc="x264 encoding - PASS 2"
ovc=x264=1
x264encopts=pass=2:threads=0:subq=6:frameref=5:partitions=all:8x8dct=1:me=umh:bframes=3:b_pyramid=normal:weight_b=1:keyint=25:bitrate=2000
oac=mp3lame=1
lameopts=aq=0:q=0
passlogfile=x264-pass1.log
mencoder -profile x264-pass1 input.avi
mencoder -profile x264-pass2 input.avi -o output.avi
x264 Single-pass Profile Example
[x264]
profile-desc="x264 encoding"
ovc=x264=1
x264encopts=crf=20:threads=0:subq=6:frameref=5:partitions=all:8x8dct=1:me=umh:bframes=3:b_pyramid=normal:weight_b=1:keyint=25
aspect=16/9
oac=mp3lame=1
lameopts=aq=0:q=0
mencoder -profile x264 input.avi -o output.avi
Posted by admin on November 4, 2014 under Tech Tips |
If you would like to add chapters to your video files, such as XviD, x264, OGG, etc., simply use the Matroska multimedia container format.
For those of you that have never created Matroska files, visit the Matroska website to find the right software for your platform. If you’re using Ubuntu Linux, install the mkvtoolnix package from the repositories. It contains all the tools you need to start working with MKV files.
sudo apt-get-install mkvtoolnix
The easiest method of creating your chapter definitions is with any text editor, using the following format. Feel free to change the name and time values accordingly. Save the file anywhere you can remember, e.g. chapter.txt.
CHAPTER01=00:00:00.000
CHAPTER01NAME=Chapter 01
CHAPTER02=00:05:00.000
CHAPTER02NAME=Chapter 02
CHAPTER03=00:10:00.000
CHAPTER03NAME=Chapter 03
CHAPTER04=00:15:00.000
CHAPTER04NAME=Chapter 04
CHAPTER05=00:20:00.000
CHAPTER05NAME=Chapter 05
If you want to create a chapter file from an existing DVD, dvdxchap is a great tool for the job if you’re using Linux. It’s part of the ogmtools package. For more info, check out the OGMtools project web site.
Installation and three examples of how to use the tool are below.
sudo apt-get install ogmtools
dvdxchap /dev/dvd > chapter.txt
dvdxchap ./VIDEO_TS/ > chapter.txt
dvdxchap video.iso > chapter.txt
mkvmerge is the only tool you need to create an MKV file. In the following examples, your source video file is called video.avi, and your destination file is video.mkv.
A simplified version of the mkvmerge syntax is as follows.
mkvmerge video.avi --chapters chapter.txt -o video.mkv
I typically like to set my default language to English, and also turn off header compression for all tracks since some players don’t play nicely with compression enabled. The syntax and example output is displayed below.
mkvmerge video.avi --default-language eng
--compression -1:none --chapters chapter.txt -o video.mkv
mkvmerge v4.2.0 ('No Talking') built on Jul 28 2010 16:47:39
'video.avi': Using the AVI demultiplexer. Opening file. This may take some time depending on the file's size.
'video.avi' track 0: Using the MPEG-4 part 2 video output module.
'video.avi' track 1: Using the MPEG audio output module.
The file 'video.mkv' has been opened for writing.
'video.avi' track 0: Extracted the aspect ratio information from the MPEG4 layer 2 video data and set the display dimensions to 712/416.
Progress: 100%
The cue entries (the index) are being written...
Muxing took 30 seconds.
That’s really all there is to it. Now any media player that supports MKV chapters will allow you to navigate them. My favorites are VLC, Mplayer, and my Western Digital media player, the WD TV Live Plus.
Verify the contents of your MKV using mkvmerge or mkvinfo.
mkvmerge -i video.mkv
File 'video.mkv': container: Matroska
Track ID 1: video (V_MS/VFW/FOURCC, XVID)
Track ID 2: audio (A_MPEG/L3)
Chapters: 13 entries
mkvinfo video.mkv
+ EBML head
|+ EBML version: 1
|+ EBML read version: 1
|+ EBML maximum ID length: 4
|+ EBML maximum size length: 8
|+ Doc type: matroska
|+ Doc type version: 2
|+ Doc type read version: 2
+ Segment, size 1325519138
|+ Seek head (subentries will be skipped)
|+ EbmlVoid (size: 4029)
|+ Segment information
| + Timecode scale: 1000000
| + Muxing application: libebml v1.0.0 + libmatroska v1.0.0
| + Writing application: mkvmerge v4.2.0 ('No Talking') built on Jul 28 2010 16:47:39
| + Duration: 5004.680s (01:23:24.680)
| + Date: Thu Aug 5 00:26:03 2010 UTC
| + Segment UID: 0x81 0x4b 0xc4 0xf1 0xf4 0x5b 0x6d 0xda 0xc5 0x40 0xc1 0x03 0x3f 0x36 0x0f 0xd9
|+ Segment tracks
| + A track
| + Track number: 1
| + Track UID: 1318207700
| + Track type: video
| + Lacing flag: 0
| + MinCache: 1
| + Codec ID: V_MS/VFW/FOURCC
| + CodecPrivate, length 40 (FourCC: XVID, 0x44495658)
| + Default duration: 40.000ms (25.000 fps for a video track)
| + Video track
| + Pixel width: 480
| + Pixel height: 416
| + Display width: 712
| + Display height: 416
| + A track
| + Track number: 2
| + Track UID: 3206714560
| + Track type: audio
| + Codec ID: A_MPEG/L3
| + Default duration: 24.000ms (41.667 fps for a video track)
| + Audio track
| + Sampling frequency: 48000
| + Channels: 2
|+ EbmlVoid (size: 1099)
|+ Chapters
| + EditionEntry
| + EditionFlagHidden: 0
| + EditionFlagDefault: 0
| + EditionUID: 585228242
| + ChapterAtom
| + ChapterUID: 4059317607
| + ChapterTimeStart: 00:00:00.000000000
| + ChapterFlagHidden: 0
| + ChapterFlagEnabled: 1
| + ChapterDisplay
| + ChapterString: Chapter 01
| + ChapterLanguage: eng
| + ChapterAtom
| + ChapterUID: 3065648262
| + ChapterTimeStart: 00:05:00.000000000
| + ChapterFlagHidden: 0
| + ChapterFlagEnabled: 1
| + ChapterDisplay
| + ChapterString: Chapter 02
| + ChapterLanguage: eng
| + ChapterAtom
| + ChapterUID: 2388361707
| + ChapterTimeStart: 00:10:00.000000000
| + ChapterFlagHidden: 0
| + ChapterFlagEnabled: 1
| + ChapterDisplay
| + ChapterString: Chapter 03
| + ChapterLanguage: eng
| + ChapterAtom
| + ChapterUID: 1448933008
| + ChapterTimeStart: 00:15:00.000000000
| + ChapterFlagHidden: 0
| + ChapterFlagEnabled: 1
| + ChapterDisplay
| + ChapterString: Chapter 04
| + ChapterLanguage: eng
| + ChapterAtom
| + ChapterUID: 1319721142
| + ChapterTimeStart: 00:20:00.000000000
| + ChapterFlagHidden: 0
| + ChapterFlagEnabled: 1
| + ChapterDisplay
| + ChapterString: Chapter 05
| + ChapterLanguage: eng
|+ EbmlVoid (size: 101)
|+ Cluster
Posted by admin on June 20, 2014 under Tech Tips |
A while back, I wanted to find a tool that would go through my entire collection of MP3’s and remove all the extra ID3 tags I didn’t want. For example, when I purchase music from Amazon, Rhapsody, and other online music stores, there are a number of tags in the files that track things like the purchase date and sales transaction ID’s. I also like to get rid of annoying comments and other hidden tags that most editors won’t even show you.
In my search for a tool, I came across this very useful post outlining a similar project. In the authors quest to do the same thing, he came up with a shell script that searches for all MP3 files, and removes tags that are not in his list of “good” tags. I usually don’t like to rehash the work someone else has done, but since I use his script so often, I thought it would be useful to repost it with only minor modifications.
Prerequisite: Install eyeD3
The script requires the eyeD3 tag editor to parse and manipulate the tag data. So be sure to install eyeD3, which should be available in your favorite Linux repository.
sudo apt-get install eyed3
Save and Modify Script
Save the following script as strip-tags.sh somewhere in your executable path.
#!/bin/bash
# Script name: strip-tags.sh
# Original Author: Ian of DarkStarShout Blog
# Site: http://darkstarshout.blogspot.com/
# Options slightly modified to liking of SavvyAdmin.com
oktags="TALB APIC TCON TPE1 TPE2 TPE3 TIT2 TRCK TYER TCOM TPOS"
indexfile=`mktemp`
#Determine tags present:
find . -iname "*.mp3" -exec eyeD3 --no-color -v {} ; > $indexfile
tagspresent=`sort -u $indexfile | awk -F): '/^<.*$/ {print $1}'
| uniq | awk -F)> '{print $1}' | awk -F( '{print $(NF)}'
| awk 'BEGIN {ORS=" "} {print $0}'`
rm $indexfile
#Determine tags to strip:
tostrip=`echo -n $tagspresent $oktags $oktags
| awk 'BEGIN {RS=" "; ORS="n"} {print $0}' | sort | uniq -u
| awk 'BEGIN {ORS=" "} {print $0}'`
#Confirm action:
echo
echo The following tags have been found in the mp3s:
echo $tagspresent
echo These tags are to be stripped:
echo $tostrip
echo
echo -n Press enter to confirm, or Ctrl+C to cancel...
read dummy
#Strip 'em
stripstring=`echo $tostrip
| awk 'BEGIN {FS="n"; RS=" "} {print "--set-text-frame=" $1 ": "}'`
# First pass copies any v1.x tags to v2.3 and strips unwanted tag data.
# Second pass removes v1.x tags, since I don't like to use them.
# Without --no-tagging-time-frame, a new unwanted tag is added. :-)
find . -iname "*.mp3"
-exec eyeD3 --to-v2.3 --no-tagging-time-frame $stripstring {} ;
-exec eyeD3 --remove-v1 --no-tagging-time-frame {} ;
echo "Script complete!"
|
To run the script, just execute it from the top level parent directory.
cd ~/Music/
strip-tags.sh
I really didn’t change a whole lot from the original, only making slight tweaks to eyeD3 options. For example, I removed colors from the eyeD3 output when creating the first list of tags, and added a line to remove v1.x ID3 tags since I don’t like to keep them around.
Be sure to edit the list of good tags identified by the “okaytags” variable. My preferred list includes the following:
oktags="TALB APIC TCON TPE1 TPE2 TPE3 TIT2 TRCK TYER TCOM TPOS"
|
TALB - Album/Movie/Show title
APIC - Attached picture (Album Art)
TCON - Content type (Genre)
TPE1 - Lead performer(s)/Soloist(s)
TPE2 - Band/orchestra/accompaniment
TPE3 - Conductor/performer refinement
TIT2 - Title/songname/content description
TRCK - Track number/Position in set
TYER - Year
TCOM - Composer
TPOS - Part of a set
Enjoy!
Posted by admin on February 21, 2013 under Tech Tips |
If you have a source video file encoded with an AC3 Dolby Digital audio stream, you can extract the audio in it’s native format using FFMpeg.
The following example shows how to identify the available audio streams of the file video.avi. Just use ffmpeg without any output options, and you can see there are two streams (0.0 and 0.1), the second is AC3 audio.
ffmpeg -i video.avi
Input #0, avi, from 'video.avi':
Duration: 01:17:57.64, start: 0.000000, bitrate: 1587 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 672x576 (snipped for brevity)
Stream #0.1: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
At least one output file must be specified
The following command will extract the AC3 audio stream to a file called audio.ac3.
ffmpeg -i video.avi -acodec copy audio.ac3
Input #0, avi, from 'video.avi':
Duration: 01:17:57.64, start: 0.000000, bitrate: 1587 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 672x576 (snipped for brevity)
Stream #0.1: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
Output #0, ac3, to 'audio.ac3':
Stream #0.0: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
Stream mapping:
Stream #0.1 -> #0.0
Press [q] to stop encoding
size= 255799kB time=4677.51 bitrate= 448.0kbits/s
video:0kB audio:255799kB global headers:0kB muxing overhead 0.000000%
Verify the file was created. The output below shows that this stream is about 250Mb.
ls -lh audio.ac3
-rw-r--r-- 1 username gmendoza 250M 2010-02-21 09:47 audio.ac3
You can now use ffmpeg again to show that audio.ac3 only contains the ac3 audio stream.
ffmpeg -i audio.ac3
Input #0, ac3, from 'audio.ac3':
Duration: 01:17:57.46, bitrate: 448 kb/s
Stream #0.0: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
At least one output file must be specified
Now that you have extracted the audio stream, you can do anything you wish with it. Enjoy.
Posted by admin on September 19, 2012 under Tech Tips |
If you would like to copy a DVD to an XviD video file using Linux, doing so from the command line offers a number of flexibility benefits over many graphical tools. Two fantastic tools for the job are lsdvd and mencoder. I like lsdvd because it provides a great deal of information in an easy to read format, and mencoder is just a phenomenal tool for multimedia encoding.
There are some pre-requisite applications you need in order to follow along. Be sure to install mplayer, mencoder, lsdvd, lame, and if your DVD’s are encrypted, the libdvdcss2 libraries. If using Ubuntu, Debian, etc, then all are available in the repositories, except libdvdcss2 which is available in the Medibuntu repositories.
Quick XviD Encoding Examples (For the Impatient)
In the following examples, we’ll use mencoder with the most basic of options, allowing mencoder to decide which video and audio streams to use. Mencoder’s choice may not be what you want, and the audio will also be converted to a high quality VBR stereo MP3. Adjust any settings as you see fit.
Single-Pass Encoding
Fixed Quantizer Value of 4 (Good quality, decent file size)
mencoder dvd:// -oac mp3lame -lameopts q=0:aq=0
-ovc xvid -xvidencopts fixed_quant=4:autoaspect -o video.avi
Fixed Quantizer Value of 2 (High quality, larger file size)
mencoder dvd:// -oac mp3lame -lameopts q=0:aq=0
-ovc xvid -xvidencopts fixed_quant=2:autoaspect -o video.avi
Two Pass Encoding
Pass 1: (no need for audio or quality settings such as bitrate)
mencoder dvd:// -nosound -passlogfile pass1.log
-ovc xvid -xvidencopts pass=1:turbo:autoaspect -o /dev/null
Pass 2 Option 1: (VBR ~ 1500 kbps)
mencoder dvd:// -oac mp3lame -lameopts q=0:aq=0 -passlogfile pass1.log
-ovc xvid -xvidencopts pass=2:autoaspect:bitrate=1500 -o video.avi
Pass 2 Option 2: (VBR ~ Restrict final video size to 1.5 Gb)
mencoder dvd:// -oac mp3lame -lameopts q=0:aq=0 -passlogfile pass1.log
-ovc xvid -xvidencopts pass=2:autoaspect:bitrate=-1500000 -o video.avi
Basic Source Selection Examples
If you are copying a DVD directly from a physical disc as the examples throughout this post will assume, the following two examples will work. The first automatically selects title 1, and the second specifies title 2.
mencoder dvd:// (other options)
mencoder dvd://2 (other options)
If you’re encoding a DVD from an ISO or similar image file, or have the contents of a DVD extracted to directory, use the -dvd-device option as shown below.
mencoder dvd:// -dvd-device video.iso (other options)
mencoder dvd:// -dvd-device /path/to/dvd_directory/ (other options)
Basic Audio Examples
To encode the selected audio stream to a high quality VBR stereo MP3 format.
mencoder dvd:// -oac mp3lame -lameopts q=0:aq=0 (other options)
If the source audio stream is encoded as AC3 or DTS 5.1 (6 Channels), you can simply copy the stream, but remember to specify 6 channels. The default is 2.
mencoder dvd:// -oac copy -channels 6 (other options)
To exclude all sound, which is useful for the first pass of a two-pass job, or if you prefer to multiplex the audio later, use the -nosound option.
mencoder dvd:// -nosound (other options)
Gathering Source Video Information for Informed Encoding Decisions
First you should identify which DVD title tracks are available, so you can determine which one you want to copy. Most DVDs will place the movie as the first track, but you may not always be that lucky. You can use lsdvd to list the number of titles, chapters, and audio tracks on your DVD.
lsdvd /dev/dvd
Disc Title: DVD_TITLE
Title: 01, Length: 01:26:08.200 Chapters: 13, Cells: 13, Audio streams: 02, Subpictures: 01
Title: 02, Length: 00:02:01.120 Chapters: 01, Cells: 01, Audio streams: 02, Subpictures: 01
Title: 03, Length: 00:02:26.120 Chapters: 01, Cells: 01, Audio streams: 02, Subpictures: 01
Longest track: 01
In the example above, we found that Title 01 is the longest at 1 hour 26 minutes, has 13 chapters and 2 audio streams.
Use lsdvd again to gather additional information about video properties of this specific title.
lsdvd -v -t 1 /dev/dvd
Disc Title: DVD_TITLE
Title: 01, Length: 01:26:08.200 Chapters: 13, Cells: 13, Audio streams: 02, Subpictures: 01
VTS: 01, TTN: 01, FPS: 25.00, Format: PAL, Aspect ratio: 4/3, Width: 720, Height: 576, DF: ?
From the output above, we see that this video is in the PAL format at 25.00 frames per second and an aspect ratio of 4/3. Use mplayer to play this title and verify it’s the one you want.
mplayer dvd://1
Gathering Source Audio Information
Use lsdvd to give you more detail on the available audio streams for the title you’re working on.
lsdvd -a -t 1 /dev/dvd
Disc Title: DVD_TITLE
Title: 01, Length: 01:26:08.200 Chapters: 13, Cells: 13, Audio streams: 02, Subpictures: 01
Audio: 1, Language: nl - Nederlands, Format: ac3, Frequency: 48000, Quantization: drc, Channels: 2, AP: 0, Content: Undefined, Stream id: 0x80
Audio: 2, Language: en - English, Format: ac3, Frequency: 48000, Quantization: drc, Channels: 2, AP: 0, Content: Undefined, Stream id: 0x81
The output above shows that there are two audio streams, both AC3 Dolby Digital, however only the second one is in English. Mencoder and mplayer allow you to specify your desired audio stream by language as shown in the following example.
mencoder dvd://1 -alang eng (other options)
If your source has multiple English streams, you can specify which particular audio ID (aid) you want. Mplayer can be used to display all available audio identifiers of a DVD. The following command is a little long but it should serve you well.
mplayer dvd://1 -identify -frames 0 -vo null 2>&1 | grep aid
audio stream: 0 format: ac3 (stereo) language: nl aid: 128.
audio stream: 1 format: ac3 (stereo) language: en aid: 129.
From the output above, the English AC3 audio stream we want is identified by aid 129. It can be specified when using mplayer and mencoder as shown below.
mencoder dvd://1 -aid 129 (other options)
Advanced Single-Pass XviD Encoding
As mentioned before, you can encode your video using a single-pass fixed quantizer mode. It may not be as efficient in size and quality as opposed to a two-pass method, but it can save some time and complexity. Here’s the more advanced encoding options I tend to use for virtually all of my XviD encoding jobs, coupled with the information we gathered from above. A fixed_quant value between 2 and 4 work very well. The lower the number the higher the quality and larger the resulting file size.
mencoder dvd://1 -alang eng -oac mp3lame -lameopts q=0:aq=0
-ovc xvid -xvidencopts fixed_quant=4:autoaspect:max_key_interval=25:
vhq=2:bvhq=1:trellis:hq_ac:chroma_me:chroma_opt:quant_type=mpeg
-o video.avi
I added a number of quality settings as discussed both in the mencoder man page and this useful link here.
One option that seems to lack a lot of documentation is the max_key_interval setting. It influences the seekability of the encoded video. By default, the max_key_interval is set to a value of 250, which adds an I-frame at a maximum interval of 250 frames. This equates to approximately every 10 seconds depending on the frame rate of your source video. I like to set the value to 25 which is pretty low and results in a slightly larger file, but provides a seek accuracy of about 1 second. That’s just my preference, so feel free to change it as you wish.
Advanced Two-Pass XviD Encoding
Using the same advanced XviD encoding options as above, here’s what a two pass encoding job would look like.
mencoder dvd:// -nosound -passlogfile pass1.log
-ovc xvid -xvidencopts pass=1:turbo:autoaspect:vhq=0:max_key_interval=25
-o /dev/null
mencoder dvd:// -oac mp3lame -lameopts q=0:aq=0 -passlogfile pass1.log
-ovc xvid -xvidencopts pass=2:autoaspect:max_key_interval=25:bitrate=1500:
vhq=2:bvhq=1:trellis:hq_ac:chroma_me:chroma_opt:quant_type=mpeg -o video.avi
Cropping Black Borders
If your video source has black borders, you can crop them out to reduce the overall size of your video. For example, you video may resemble the following diagram.
Video with black borders
These borders can be cropped with a video filter -vf crop=w:h:x:y where w, h, x and y are the width, height, x and y coordinates. To help determine which crop values are appropriate, first play your video with mplayer using the -vf cropdetect option, and seek through the movie to bright points of the movie where the black borders are clearly visible. Dark opening scenes may give you inaccurate edge readings.
mencoder dvd:// -vf cropdetect
(snipped for brevity)
[CROP] Crop area: X: 6..711 Y: 0..575 (-vf crop=704:576:8:0).0 0
[CROP] Crop area: X: 6..711 Y: 0..575 (-vf crop=704:576:8:0).0 0
[CROP] Crop area: X: 6..711 Y: 0..575 (-vf crop=704:576:8:0).0 0
[CROP] Crop area: X: 6..711 Y: 0..575 (-vf crop=704:576:8:0).0 0
[CROP] Crop area: X: 6..711 Y: 0..575 (-vf crop=704:576:8:0).0 0
Copy the values that mplayer displays in the background terminal as the example above shows and use them like the following.
mencoder dvd:// -vf crop=704:576:8:0 (other options)
Conclusion
I hope this post provides you with detail that helps you with your DVD encoding endeavors. Please feel free to post your comments, questions and tips. If needed, I’ll adjust the post to include your valuable input!
Posted by admin on February 13, 2010 under Tech Tips |
3gp is the container format used when recording video with many mobile phones, which can be a pain when trying to view them using a number of multimedia players. Fortunately, converting videos from 3gp to XviD AVI is easy with FFmpeg.
Usually, there’s not much to the quality of these types of source video files, so many of the more complex video and audio options aren’t needed. A simple FFmpeg command that retains as much quality as possible would look like the following.
ffmpeg -i video.3gp -acodec libmp3lame -vcodec libxvid -qscale 2 -f avi video.avi
Posted by admin on December 15, 2009 under Tech Tips |
Previously, I described how to Extract Audio from Video Files to WAV using Mplayer. Another method using FFmpeg instead of Mplayer was also pointed out in the post titled Add Stereo Audio Tracks to MKV Files, and I figured it would be useful to outline the quick one-step process in a post all by itself.
Here’s an example of extracting the audio from a video file called video.mkv and saving it to a file called audio.wav. This very well could have been an AVI, MPEG, or any other video format that FFmpeg can decode.
ffmpeg -i video.mkv -acodec pcm_s16le -ac 2 audio.wav
It should also be mentioned that your source video file may have multiple audio channels or streams. For example, you may have both English AC3 and DTS channels, but you may also have other audio streams for other languages, directors comments, etc. If you want more control over which stream you are using, first identify them all with ffmpeg.
ffmpeg -i video.mkv
[snipped for brevity]
Input #0, matroska, from 'video.mkv':
Duration: 01:30:38.78, start: 0.000000, bitrate: N/A
Stream #0.0(eng): Video: h264, yuv420p, 1280x720, PAR 1:1 DAR 16:9, 23.98 tbr, 1k tbn, 47.95 tbc
Stream #0.1(eng): Audio: ac3, 48000 Hz, 5.1, s16
Stream #0.2(eng): Subtitle: 0x0000
Stream #0.3(heb): Audio: mp3, 48000 Hz, stereo, s16
Stream #0.4(heb): Subtitle: 0x0000
Stream #0.5: Attachment: 0x0000
Stream #0.6: Attachment: 0x0000
At least one output file must be specified
From the example above, you see that Stream #0.0 is labeled as being an English video stream with h264 encoding. Stream #0.1 and #0.3 are both audio streams, but #0.1 is English AC3 5.1 and #0.3 is Hebrew MP3 stereo. Simply reference the stream id with the -map option in the following format.
ffmpeg -i video.mkv -map 0:1 -acodec pcm_s16le -ac 2 audio.wav
[snipped for brevity]
Output #0, wav, to 'audio.wav':
Stream #0.0(eng): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream mapping:
Stream #0.1 -> #0.0
[snipped for brevity]
Now that you have a PCM WAV file, you can manipulated it however you like, e.g. encode to MP3, OGG, FLAC, etc.
lame -V0 -q0 --vbr-new audio.wav audio.mp3
oggenc -q6 audio.wav
flac audio.wav
Posted by admin on November 11, 2009 under Tech Tips |
If you have a video vile that you wish to convert and burn to DVD, you can do so from a Linux command line very easily. We will use FFmpeg for the video conversion, DVDAuthor to create the DVD file system structure, and Growisofs to burn the DVD.
Using FFmpeg, simply specify your input file, the target format, resolution and an output file name. While the following is an over simplified example, it will more than likely work very nicely in most scenarios. The source video file is movie.avi, the target will be formatted for NTSC, and a standard DVD resolution of 720×480 will be used to create a new video file called movie.mpg. There are many additional options that FFMpeg can use to increase quality, so be sure to check out the documentation.
ffmpeg -i movie.avi -target ntsc-video -s 720x480 movie.mpg
Next, you will need to take your new movie.mpg file, and create a DVD file structure that you will burn to disc. Just create a folder that will serve as the parent directory of your DVD. I Like to name it after the title of the movie. Then you will use dvdauthor to create a title set and table of contents and no DVD menus. The movie will just play. 
mkdir MOVIE_TITLE
dvdauthor -o MOVIE_TITLE/ -t movie.mpg
dvdauthor -o MOVIE_TITLE/ -T
The dvdauthor -t option creates a title track in the VIDEO_TS directory. If you list the contents after running the first command, you’ll see the corresponding VTS_01_0.BUP, VTS_01_0.IFO, and VTS_01_X.VOB files. The -T option creates a table of contents for all title sets in the file system, which are listed as VIDEO_TS.BUP and VIDEO_TS.IFO.
You are now ready to burn the DVD. In the following command, we will use the -Z option to burn an initial session to the disc, the -dvd-video option to generate a DVD-Video compliant UDF file system, and the -V option to give the disc a Volume ID. This Volume ID is read by your computer to and displays as a nice human readable title typically underneath the icon representing the disc. The -dvd-video and -V options are actually part of the mkisofs (genisoimage) command sets, so they do not show up in the growisofs man pages.
growisofs -Z /dev/dvdrw -dvd-video -V MOVIE_TITLE MOVIE_TITLE/
Notice, you do not need to generate an ISO file to burn the DVD. This would only waste space if your intention is not to distribute or store the video as a disc image. To create the image however, that’s as easy as the following.
genisoimage -o MOVIE_TITLE.iso -dvd-video MOVIE_TITLE/
Posted by admin on November 3, 2009 under Tech Tips |
If you want to gain quick insight into the basic properties of a video file from the Linux command line, there’s a few really easy methods. The information you might be interested in are audio and video codecs, resolution, frame rates, bitrates, etc.
Using mplayer, you can see some basic information about a video file. For example, the following video is using the WMV3 video codec at the resolution of 1280×720 (720p), the bitrate of 3000 kbps, etc.
mplayer video.wmv -vo null -ao null -frames 0 2>&1 /dev/null | egrep "(VIDEO|AUDIO)"
VIDEO: [WMV3] 1280x720 24bpp 1000.000 fps 3000.0 kbps (366.2 kbyte/s)
AUDIO: 44100 Hz, 2 ch, s16le, 96.0 kbit/6.80% (ratio: 12003->176400)
The audio rate is shown to be 44100 Hz using 2-Channel stereo, but the codec is not listed. You can get additional information with the -identify option.
mplayer video.wmv -identify -vo null -ao null -frames 0 2>&1 /dev/null | egrep "(^ID|VIDEO|AUDIO)"
ID_AUDIO_ID=1
ID_VIDEO_ID=2
VIDEO: [WMV3] 1280x720 24bpp 1000.000 fps 3000.0 kbps (366.2 kbyte/s)
ID_CLIP_INFO_NAME0=name
ID_CLIP_INFO_VALUE0=
ID_CLIP_INFO_NAME1=author
ID_CLIP_INFO_VALUE1=
ID_CLIP_INFO_NAME2=copyright
ID_CLIP_INFO_VALUE2=
ID_CLIP_INFO_NAME3=comments
ID_CLIP_INFO_VALUE3=
ID_CLIP_INFO_N=4
ID_FILENAME=video.wmv
ID_DEMUXER=asf
ID_VIDEO_FORMAT=WMV3
ID_VIDEO_BITRATE=3000000
ID_VIDEO_WIDTH=1280
ID_VIDEO_HEIGHT=720
ID_VIDEO_FPS=1000.000
ID_VIDEO_ASPECT=1.7778
ID_AUDIO_FORMAT=353
ID_AUDIO_BITRATE=0
ID_AUDIO_RATE=0
ID_AUDIO_NCH=0
ID_LENGTH=2116.00
ID_VIDEO_ASPECT=1.7778
ID_VIDEO_CODEC=wmv9dmo
AUDIO: 44100 Hz, 2 ch, s16le, 96.0 kbit/6.80% (ratio: 12003->176400)
ID_AUDIO_BITRATE=96024
ID_AUDIO_RATE=44100
ID_AUDIO_NCH=2
ID_AUDIO_CODEC=ffwmav2
Another great tool for identifying video attributes is idvid. idvid comes with the tovid package, so be sure to install it from your repository. It is a bit slow, but the output is very clean and easy to interpret.
idvid video.wmv
--------------------------------
idvid
Video identification script
Part of the tovid suite, version 0.31
http://www.tovid.org
--------------------------------
Analyzing file: 'video.wmv'. This may take several minutes...
=========================================================
File: video.wmv
Width: 1280 pixels
Height: 720 pixels
Aspect ratio: 1.77:1
Frames: 63352
Duration: 00:35:13 hours/mins/secs
Framerate: 1000.000 frames per second
Video format: WMV3
Video bitrate: 3000000 bits per second
---------------------------
Audio track 1 (Stream 0.0, AID 0):
---------------------------
Codec: wmav2
Bitrate: 0000 bits per second
Sampling rate: 44100 Hz
=========================================================
Audio is compliant with the following formats:
Not compliant with (S)VCD or DVD
Video is compliant with the following formats:
Not compliant with (S)VCD or DVD
This video does not seem to be compliant with (S)VCD or DVD
standards. If you burn it to a video disc, it may not work.
=========================================================
Finally, another tool that works very well is exiftool. It’s available in the libimage-exiftool-perl package. The output is also very straight forward, and easy to interpret. It’s also a lot faster than idvid because the tool only displays metadata, which in some cases can be misleading.Mplayer and tovid actually probe the video, providing very accurate information at the cost of speed.
exiftool video.wmv
ExifTool Version Number : 7.30
File Name : video.wmv
Directory : .
File Modification Date/Time : 2009:04:20 09:21:58
File Type : WMV
MIME Type : video/x-ms-wmv
File ID : 12341234-1234-1234-1234-123412341234
File Size : 823200182
Creation Date : 2009:03:31 02:52:55Z
Data Packets : 102833
Play Duration : 35:16
Send Duration : 35:13
Preroll : 3000
Flags : 2
Min Packet Size : 8000
Max Packet Size : 8000
Max Bitrate : 3122812
Is VBR : False
Audio Codec Name : Windows Media Audio 9.2
Audio Codec Description : 96 kbps, 44 kHz, stereo 1-pass CBR
Video Codec Name : Windows Media Video 9
Video Codec Description : Professional
Audio Codec ID : Windows Media Audio V2 V7 V8 V9 / DivX audio (WMA) / Alex AC3 Audio
Audio Channels : 2
Audio Sample Rate : 44100
Stream Type : Video
Error Correction Type : No Error Correction
Time Offset : 0 s
Stream Number : 2
Image Width : 1280
Image Height : 720
Title :
Author :
Copyright :
Description :
Rating :
Image Size : 1280x720
As always, comments and additional tips are welcome!
Posted by admin on October 11, 2009 under Tech Tips |
You can extract the audio from a video file using mplayer and save the result to a WAV file, which you can then manipulate to your hearts content. For example, you may want to compress the audio to a stereo MP3 or OGG.
The following command instruct that the audio output (-ao) should be redirected out to a PCM WAV file as fast as possible, while suppressing all video output.
mplayer -ao pcm:fast:file=audio.wav -vo null -vc null video.avi
Convert the resulting WAV to MP3. The following is a great way to convert your WAV files to a high quality Variable Bitrate MP3. See the man page for a decent tutorial on the available options.
lame -V0 -q0 --vbr-new audio.wav audio.mp3
