AVI to MP4

ffmpeg -i input.avi -c:v libx264 -crf 19 -preset slow -c:a libfaac -b:a 192k -ac 2 out.mp4

if libfaac isn't available, use this:

ffmpeg -i input.avi -c:v libx264 -crf 19 -preset slow -c:a aac -strict experimental -b:a 192k -ac 2 out.mp4

wmv to MP4

ffmpeg -i input.wmv -c:v libx264 -crf 19 -preset slow -c:a aac -strict experimental -b:a 192k -ac 2 out.mp4

FLV to MP4

ffmpeg -i filename.flv -c:v libx264 -crf 19 -strict experimental filename.mp4

MOV to MP4

if MOV has h.264 already:

ffmpeg -i input.mov -vcodec copy -acodec copy output.mp4

if not:

ffmpeg -i {input}.mov -vcodec h264 -acodec aac -strict -2 {output}.mp4

For ripping DVDs, use makemkv to rip the VOB files to MKV files.  Then use ffmpeg to convert to mp4

MKV

ffmpeg -i input.mkv -c:v libx264 -crf 19 -preset slow -acodec aac -b:a 192k -ac 2 out.mp4 #straight output

ffmpeg -i input.mkv -vf yadif -c:v libx264 -crf 19 -preset slow -acodec aac -b:a 192k -ac 2 out.mp4 #deinterlaced

ffmpeg -i input.mkv -c:v libx264 -flags +ildct+ilme -crf 19 -preset slow -acodec aac -b:a 192k -ac 2 out.mp4 #interlaced

ffmpeg -i input.mkv -c:v libx264 -flags +ildct+ilme -crf 19 -preset slow -acodec aac -b:a 192k -ac 2 -c:s mov_text out.mp4 #interlaced and subtitles included

Join Webm video and m4a audio:
ffmpeg -i input_video.webm -i input_audio.m4a -vcodec h264 -acodec aac -strict -2 output_video.mp4






How to trim a video:

ffmpeg -ss 00:01:00 -i input.mp4 -to 00:02:00 -c copy output.mp4

How to increase/decrease volume:

To increase the volume of the first audio track for 10dB use:

ffmpeg -i inputfile -vcodec copy -af "volume=10dB" outputfile

To decrease the volume of the first audio track for 5dB use:

ffmpeg -i inputfile -vcodec copy -af "volume=-5dB" outputfile

Concatenation of files with same codecs

There are two methods within ffmpeg that can be used to concatenate files of the same type: the concat ''demuxer'' and the concat ''protocol''. The demuxer is more flexible - it requires the same codecs, but different container formats can be used; and it can be used with any container formats, while the protocol only works with a select few containers. However, the concat protocol is available in older versions of ffmpeg, where the demuxer isn't.

Concat demuxer

The concat demuxer was added to FFmpeg 1.1. You can read about it in the documentation.

Instructions

Create a file mylist.txt with all the files you want to have concatenated in the following form (lines starting with a # are ignored):

# this is a comment
file '/path/to/file1'
file '/path/to/file2'
file '/path/to/file3'

Note that these can be either relative or absolute paths. Then you can stream copy or re-encode your files:

ffmpeg -f concat -i mylist.txt -c copy output

It is possible to generate this list file with a bash for loop, or using printf. Either of the following would generate a list file containing every *.wav in the working directory:

# with a bash for loop
for f in ./*.wav; do echo "file '$f'" >> mylist.txt; done
# or with printf
printf "file '%s'\n" ./*.wav > mylist.txt

On Windows Command-line:

(for %i in (*.wav) do @echo file '%i') > mylist.txt