mp4 interview questions
Top mp4 frequently asked interview questions
Usually I open the context menu right clicking on the image. Now theres no option for "save image as", just options for the WEBM/MP4 format.
Source: (StackOverflow)
Having an MP4 video file I'd like to get just the audio track of it. What makes my question different from the others is that I don't want to convert it (like to MP3 or anything) - I'd prefer to keep exactly the same AAC audio stream that is embedded in the MP4 file without recoding.
I use to play such MP4 files with an audio player (foobar2000, which just ignores the video track in it) on my desktop PC but I'd like to strip the video track off to save space and battery of my handheld.
Source: (StackOverflow)
I'm having trouble finding a cli application that can take a video file (avi, mkv, and mp4 preferably) and cut out very short clips (2-6 seconds) with precision time accuracy. I've tried ffmpeg, mencoder, avidemux, and mp4box but they all cut on keyframes which creates 6+ second clips. Is there a tool that will re-encode the input file and cut the accurate time or cut inaccurately, re-encode, and then cut accurately?
Source: (StackOverflow)
This question already has an answer here:
Currently I'm converting .flv flash files to .webm and .mp4 files to be used with an HTML5 video player.
_
I use this ffmpeg command for WEBM: ffmpeg -i filename.flv -vcodec libvpx -acodec libvorbis filename.webm
which works great and the file size stays relatively the same (imporatant).
_
For MP4 I'm using the following: ffmpeg -i filename.flv -sameq -ar 22050 filename.mp4
It converts to .mp4 fine and prevents any quality loss but the file size almost triples in size.
What ffmpeg formula could be used to convert to MP4 without losing too much quality and preventing a much higher file size?
Source: (StackOverflow)
Im trying to use ffmpeg to convert my flv files to mp4 to play them on iOS devices but the converted video has a much worse quality than the original one.
Here is the command i use:
ffmpeg -i input.flv -ar 22050 output.mp4
I would really appreciate if someone could provide me with the best settings for flv to mp4 conversion.
Source: (StackOverflow)
I have a ton of MKV files I need to convert to MP4 and my chosen software is Handbrake.
I'm stuck on which settings would be best for the conversion. I want to retain full quality. Do I just convert with the original settings and not change anything or is there any specific thing I need to change?
Source: (StackOverflow)
I have one large MP4 file. I am attempting to split it into smaller files.
ffmpeg -i largefile.mp4 -sameq -ss 00:00:00 -t 00:50:00 smallfile.mp4
I thought using -sameq would keep the same quality settings. However, I must not understand what that does.
I'm looking to keep the same quality (audio/video) and compression with the split files. However, this setting makes the split files much larger.
What flag(s) do I need to set to keep the same quality and attributes in the split files while maintaining the same quality to size ratio?
For instance if my original file is about 12 GB and is 1920x1080 with a bitrate of 10617kbps and a framerate of 23 frames/sec and 6 channel audio with 317kbps, I would like the split files to be the same only a third of this size (if i split it into three pieces).
Source: (StackOverflow)
Google Chrome on Windows comes with support for the above media formats, however, Chromium does not.
I want to add support for my own personal use, how can I do this?
I know that on Ubuntu this is solvable by installing the chromium-codecs-ffmpeg-extra and chromium-codecs-ffmpeg-nonfree packages, however I didn't find anything for Windows.
Source: (StackOverflow)
Yesterday I was filming a scene with my phone but suddenly the application crashed and when I try to open the m4v generated it says that is corrupted.
I have downloaded the video files (around 36MB) on my PC and I am trying to open and repair it. Can you suggest me a way to do it?
FFMPEG info
As suggested in comments I try check what FFMPEG says me about that file with this command
ffmpeg.exe -i VID_20120425_144739.m4v -c:v copy -c:a copy out.mp4 2> log.txt
Here it is the result:
ffmpeg version N-40126-ga4b58fd Copyright (c) 2000-2012 the FFmpeg developers
built on Apr 26 2012 03:29:50 with gcc 4.6.3
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 51. 47.100 / 51. 47.100
libavcodec 54. 15.100 / 54. 15.100
libavformat 54. 3.100 / 54. 3.100
libavdevice 53. 4.100 / 53. 4.100
libavfilter 2. 72.100 / 2. 72.100
libswscale 2. 1.100 / 2. 1.100
libswresample 0. 11.100 / 0. 11.100
libpostproc 52. 0.100 / 52. 0.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 003fc940] moov atom not found
VID_20120425_144739.m4v: Invalid data found when processing input
Latest two lines are displayed in red.
Source: (StackOverflow)
I have two halves of a single show in two .MP4 files, encoded in H264. I would like to join them without re-encoding.
Is this possible?
I managed to create a joined video as a Quicktime file (.mov) using Quicktime Pro, but then Quicktime Pro will not convert it back to .MP4 without re-encoding. This may be because looking inside the .mov file, the two H264 videos are in there still separated as individual "objects".
I am also struggling with MPEG StreamClip without reaching a real solution. But I may have missed something.
Note that I do not have the same issue with MPEG2 files. I can export them to a .MPEG container or a .TS file for example, and then I can join them without re-encoding using MPEG Streamclip.
Any suggestion welcome, preferably using Mac software.
Source: (StackOverflow)
I have a digital camera that records nice 1080p H.264 format but unfortunately it uses the MOV container format. Basically I have nothing but the camera and VLC that play this format natively.
Is there a tool out there to convert the video to a format by just replacing the container format? That'd be a lot faster as the encoding is perfectly fine.
It'd be nice to select the folder and convert everything over to a more respectable container format like MP4.
I don't want to touch the actual quality of the video I want the conversion to be as fast as possible.
Source: (StackOverflow)
Release group LOL does an excellent job at encoding their releases on The Vampire Diaries (on other shows like How I Met Your Mother the bitrate is higher, so doesn't seem this effective).
About 200 MB each ~45mins MP4 file, amazing quality considering.
I just wonder what settings and what software they use. I've tried to get info from these files using MediaInfo, then use the settings in HandBrake, but I didn't really succeed.
Could anyone please help me? I don't have much knowledge about encoding/compressing.
Source: (StackOverflow)
I'm trying to encode an image-sequence (frame0001.png, frame0002.png, ... , frame0160.png) into an x264 video using the following command:
ffmpeg -i frame%04d.png -sameq -r 24 out.mp4
After encoding, it says drop=5 and indeed there are noticeable “jumps” in the video.
It appears someone else had a similar problem, but for me the accepted answer isn't very useful since I'd like to have no frames dropped.
Is a switch missing from the command? Or am I doing something else wrong?
Edit: Added console output:
ffmpeg version N-42347-g299387e Copyright (c) 2000-2012 the FFmpeg developers
built on Jul 8 2012 15:46:39 with gcc 4.7.1
configuration: --disable-static --enable-shared --enable-gpl --enable-version3
--disable-w32threads --enable-runtime-cpudetect --enable-avisynth --enable-bzli
b --enable-frei0r --enable-libass --enable-libcelt --enable-libopencore-amrnb --
enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lam
e --enable-libnut --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
--enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc
--enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --en
able-libxavs --enable-libxvid --enable-zlib
libavutil 51. 64.100 / 51. 64.100
libavcodec 54. 33.100 / 54. 33.100
libavformat 54. 15.102 / 54. 15.102
libavdevice 54. 1.100 / 54. 1.100
libavfilter 3. 1.100 / 3. 1.100
libswscale 2. 1.100 / 2. 1.100
libswresample 0. 15.100 / 0. 15.100
libpostproc 52. 0.100 / 52. 0.100
Input #0, image2, from 'frame%04d.png':
Duration: 00:00:06.40, start: 0.000000, bitrate: N/A
Stream #0:0: Video: png, rgb24, 1920x1080, 25 fps, 25 tbr, 25 tbn, 25 tbc
[graph 0 input from stream 0:0 @ 01cd1f60] w:1920 h:1080 pixfmt:rgb24 tb:1/25 fr
:25/1 sar:0/1 sws_param:flags=2
[output stream 0:0 @ 01cd2220] No opaque field provided
[auto-inserted scaler 0 @ 01cd3540] w:1920 h:1080 fmt:rgb24 sar:0/1 -> w:1920 h:
1080 fmt:yuv420p sar:0/1 flags:0x4
[libx264 @ 01cd0dc0] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64
[libx264 @ 01cd0dc0] profile High, level 4.0
[libx264 @ 01cd0dc0] 264 - core 125 r2200 999b753 - H.264/MPEG-4 AVC codec - Cop
yleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deb
lock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 m
e_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chro
ma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 i
nterlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24 scenec
ut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=
0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'out.mp4':
Metadata:
encoder : Lavf54.15.102
Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1920x1080, q=-1-
-1, 24 tbn, 24 tbc
Stream mapping:
Stream #0:0 -> #0:0 (png -> libx264)
Press [q] to stop, [?] for help
frame= 8 fps=0.0 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 15 fps= 15 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 22 fps= 14 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 29 fps= 14 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 36 fps= 14 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 43 fps= 14 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 47 fps= 11 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s
frame= 53 fps= 11 q=28.0 size= 111kB time=00:00:00.04 bitrate=21735.2kbits
frame= 59 fps= 11 q=28.0 size= 268kB time=00:00:00.29 bitrate=7527.8kbits/
frame= 63 fps= 10 q=28.0 size= 375kB time=00:00:00.45 bitrate=6708.1kbits/
frame= 69 fps= 10 q=28.0 size= 538kB time=00:00:00.70 bitrate=6219.6kbits/
frame= 74 fps= 10 q=28.0 size= 675kB time=00:00:00.91 bitrate=6032.7kbits/
frame= 79 fps= 10 q=28.0 size= 802kB time=00:00:01.12 bitrate=5840.7kbits/
frame= 84 fps= 10 q=28.0 size= 922kB time=00:00:01.33 bitrate=5662.9kbits/
frame= 89 fps=9.9 q=28.0 size= 1060kB time=00:00:01.54 bitrate=5633.3kbits/
frame= 94 fps=9.9 q=28.0 size= 1186kB time=00:00:01.75 bitrate=5551.2kbits/
frame= 98 fps=9.7 q=28.0 size= 1309kB time=00:00:01.91 bitrate=5594.3kbits/
frame= 103 fps=9.7 q=28.0 size= 1436kB time=00:00:02.12 bitrate=5536.4kbits/
frame= 107 fps=9.6 q=28.0 size= 1533kB time=00:00:02.29 bitrate=5481.7kbits/
frame= 112 fps=9.5 q=28.0 size= 1654kB time=00:00:02.50 bitrate=5421.3kbits/
frame= 117 fps=9.4 q=28.0 size= 1781kB time=00:00:02.70 bitrate=5386.9kbits/
frame= 123 fps=9.4 q=28.0 size= 1925kB time=00:00:02.95 bitrate=5331.5kbits/
frame= 128 fps=9.4 q=28.0 size= 2030kB time=00:00:03.16 bitrate=5250.8kbits/
frame= 133 fps=9.4 q=28.0 size= 2210kB time=00:00:03.37 bitrate=5363.8kbits/
frame= 138 fps=9.3 q=28.0 size= 2356kB time=00:00:03.58 bitrate=5386.0kbits/
frame= 142 fps=9.3 q=28.0 size= 2465kB time=00:00:03.75 bitrate=5384.3kbits/
frame= 147 fps=9.3 q=28.0 size= 2602kB time=00:00:03.95 bitrate=5385.0kbits/
frame= 151 fps=9.2 q=28.0 size= 2706kB time=00:00:04.12 bitrate=5374.3kbits/
frame= 155 fps=9.2 q=28.0 size= 2812kB time=00:00:04.29 bitrate=5367.7kbits/
frame= 155 fps=7.0 q=28.0 Lsize= 4129kB time=00:00:06.37 bitrate=5306.4kbits
/s dup=0 drop=5
video:4128kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.035320%
[libx264 @ 01cd0dc0] frame I:2 Avg QP:21.97 size: 79850
[libx264 @ 01cd0dc0] frame P:153 Avg QP:23.43 size: 26579
[libx264 @ 01cd0dc0] mb I I16..4: 9.6% 70.5% 19.9%
[libx264 @ 01cd0dc0] mb P I16..4: 7.0% 15.3% 0.7% P16..4: 45.2% 9.1% 2.2%
0.0% 0.0% skip:20.5%
[libx264 @ 01cd0dc0] 8x8 transform intra:66.7% inter:85.7%
[libx264 @ 01cd0dc0] coded y,uvDC,uvAC intra: 38.6% 58.0% 6.0% inter: 16.2% 27.2
% 0.2%
[libx264 @ 01cd0dc0] i16 v,h,dc,p: 35% 29% 17% 19%
[libx264 @ 01cd0dc0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 26% 21% 31% 3% 4% 5% 4%
4% 3%
[libx264 @ 01cd0dc0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 19% 13% 5% 8% 9% 7%
6% 4%
[libx264 @ 01cd0dc0] i8c dc,h,v,p: 49% 23% 23% 5%
[libx264 @ 01cd0dc0] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 01cd0dc0] ref P L0: 84.5% 10.9% 3.5% 1.1%
[libx264 @ 01cd0dc0] kb/s:5235.14
Source: (StackOverflow)
This question already has an answer here:
How can I concatenate or merge 2 or more MP4 files, in a final output MP4 file also?
I have tried in the DOS window to use the COPY command (I have read it somewhere) but it doesn't function well.
Source: (StackOverflow)