Newest 'ffmpeg' Questions - Stack Overflow

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  • Changing YUV values of AVFrames

    31 janvier 2012, par Kage

    I'm trying to apply an effect to a video by altering the YUV values using FFMpeg programmatically in C.

    Let's say I want to increase the luminescence of each pixel of each frame by 10.

    At the moment I can open a video, get the video stream, find a frame, decode the frame, alter the YUV values of the AvFrame->data, encode the frame, and save the frame to be played back.

    When I play back the video, the first frame looks as expected, but the next is even brighter and the one after that is even brighter, and each frame seems to be having more and more added to the Y values instead of just 10.

    I tried changing the code so instead of altering the pixels for each frame, it just alters the first AVFrame's data. However when I play the video back, it is not only the first frame that has been altered, but like the first 30 or so frames.

    Why are the other frames effected when I only change the AVFrame->data of the first frame?

  • What's the different between asm instruction "ldr" and "ldr_post" ?

    30 janvier 2012, par ciphor

    I encountered some compilation errors when trying to migrate latest ffmpeg to iOS platform. Those errors came from the GNU assembler (gas), which seems unable to handle some asm instructions in the latest ffmpeg.

    For example:

    libavcodec/arm/dsputil_armv6.S:109:bad instruction 'ldr_post r4,r1,r2'

    However, instruction 'ldr_post' is not found in previous version of ffmpeg (more specific, version 0.7).

    My question is, what is the difference between 'ldr_post' and 'ldr'? Can I change 'ldr_post' to the combination of a few simpler instructions, to avoid these compilation errors?

  • how to install ffmpeg in cpanel

    30 janvier 2012, par Ajay Chthri

    i'm using dedicated server(linux) so i need to install ffmpeg in cpanel so here ffmpeg i found in Main >> Software >> Install a Perl Module but i writing script in php so how can i install ffmpeg phpperl

    when i'am trying to install ffmpeg in perl module i get this response 

    Checking C compiler....C compiler (/usr/bin/cc) OK (cached Tue Jan 17 19:16:31 2012)....Done
CPAN fallback is disabled since /var/cpanel/conserve_memory exists, and cpanm is available.
Method: Using Perl Expect, Installer: cpanm
You have make /usr/bin/make
Falling back to HTTP::Tiny 0.009
You have /bin/tar: tar (GNU tar) 1.15.1
You have /usr/bin/unzip
You have Cpanel::HttpRequest 2.1
Testing connection speed...(using fast method)...Done
Ping:2 (ticks) Testing connection speed to cpan.knowledgematters.net using pureperl...(28800.00 bytes/s)...Done
Ping:2 (ticks) Testing connection speed to cpan.develooper.com using pureperl...(22233.33 bytes/s)...Done
Ping:2 (ticks) Testing connection speed to cpan.schatt.com using pureperl...(32750.00 bytes/s)...Done
Ping:3 (ticks) Testing connection speed to cpan.mirror.facebook.net using pureperl...(14050.00 bytes/s)...Done
Ping:2 (ticks) Testing connection speed to cpan.mirrors.hoobly.com using pureperl...(5150.00 bytes/s)...Done
Five usable mirrors located
Ping:0 (ticks) Testing connection speed to 208.109.109.239 using pureperl...(28950.00 bytes/s)...Done
Ping:2 (ticks) Testing connection speed to 208.82.118.100 using pureperl...(19300.00 bytes/s)...Done
Ping:1 (ticks) Testing connection speed to 69.50.192.73 using pureperl...(19300.00 bytes/s)...Done
Three usable fallback mirrors located
Mirror Check passed for cpan.schatt.com (/index.html)
Searching on cpanmetadb ...
Fetching http://cpanmetadb.cpanel.net/v1.0/package/Video::FFmpeg?cpanel_version=11.30.5.6&cpanel_tier=release (connected:0).......(request attempt 1/12)...Using dns cache file /root/.HttpRequest/cpanmetadb.cpanel.net......searching for mirrors (mirror search attempt 1/3)......5 usable mirrors located. (less then expected)......mirror search success......connecting to 208.74.123.82...@208.74.123.82......connected......receiving...100%......request success......Done
Searching Video::FFmpeg on cpanmetadb (http://cpanmetadb.cpanel.net/v1.0/package/Video::FFmpeg?cpanel_version=11.30.5.6&cpanel_tier=release) ...
Fetching http://cpanmetadb.cpanel.net/v1.0/package/Video::FFmpeg?cpanel_version=11.30.5.6&cpanel_tier=release (connected:1).......(request attempt 1/12)...@208.74.123.82......connected......receiving...100%......request success......Done
Source: fastest CPAN mirror ... --> Working on Video::FFmpeg
Fetching http://cpan.schatt.com//authors/id/R/RA/RANDOMMAN/Video-FFmpeg-0.47.tar.gz ... Fetching http://cpan.schatt.com/authors/id/R/RA/RANDOMMAN/Video-FFmpeg-0.47.tar.gz (connected:1).......(request attempt 1/12)...Resolving cpan.schatt.com...(resolve attempt 1/65)......connecting to 66.249.128.125...@66.249.128.125......connected......receiving...25%...50%...75%...100%......request success......Done
OK
Unpacking Video-FFmpeg-0.47.tar.gz
Video-FFmpeg-0.47/
Video-FFmpeg-0.47/Changes
Video-FFmpeg-0.47/FFmpeg.xs
Video-FFmpeg-0.47/MANIFEST
Video-FFmpeg-0.47/META.yml
Video-FFmpeg-0.47/Makefile.PL
Video-FFmpeg-0.47/README
Video-FFmpeg-0.47/lib/
Video-FFmpeg-0.47/lib/Video/
Video-FFmpeg-0.47/lib/Video/FFmpeg/
Video-FFmpeg-0.47/lib/Video/FFmpeg/AVFormat.pm
Video-FFmpeg-0.47/lib/Video/FFmpeg/AVStream/
Video-FFmpeg-0.47/lib/Video/FFmpeg/AVStream/Audio.pm
Video-FFmpeg-0.47/lib/Video/FFmpeg/AVStream/Subtitle.pm
Video-FFmpeg-0.47/lib/Video/FFmpeg/AVStream/Video.pm
Video-FFmpeg-0.47/lib/Video/FFmpeg/AVStream.pm
Video-FFmpeg-0.47/lib/Video/FFmpeg.pm
Video-FFmpeg-0.47/ppport.h
Video-FFmpeg-0.47/t/
Video-FFmpeg-0.47/t/Video-FFmpeg.t
Video-FFmpeg-0.47/test
Video-FFmpeg-0.47/test.mp4
Video-FFmpeg-0.47/typemap
Entering Video-FFmpeg-0.47
Checking configure dependencies from META.yml
META.yml not found or unparsable. Fetching META.yml from search.cpan.org
Fetching http://search.cpan.org/meta/Video-FFmpeg-0.47/META.yml (connected:1).......(request attempt 1/12)...Resolving search.cpan.org...(resolve attempt 1/65)......connecting to 199.15.176.161...@199.15.176.161......connected......receiving...100%......request success......Done
Configuring Video-FFmpeg-0.47 ... Running Makefile.PL
Perl v5.10.0 required--this is only v5.8.8, stopped at Makefile.PL line 1.
BEGIN failed--compilation aborted at Makefile.PL line 1.
N/A
! Configure failed for Video-FFmpeg-0.47. See /home/.cpanm/build.log for details.
Perl Expect failed with non-zero exit status: 256

All available perl module install methods have failed

    guide me how can i install ffmpeg in cPanel

    Thanks for advance.

  • Ffmpeg Video Codec

    30 janvier 2012, par cilmaz

    I split video like this:

    ffmpeg -ss 00:15:00 -t 00:15:00 -i life.mp4 -acodec copy -vcodec copy life-2.mp4

    After the process i want to play splitted file on flash player (JW Player), it doesnt starts. It waits to download all af video and then start. But the source video (life.mp4) starts playing immediately. Why?

  • Trouble linking ffmpeg example source code

    30 janvier 2012, par Leonard Teo

    I managed to build ffmpeg and libx264 on my Ubuntu 11.10 machine from source.

    I'm trying to work on the example source file decoding_encoding.c. The examples comes with a makefile, so I can just type in "make all" and it magically compiles and links everything. Now, I'm trying to compile and link from the command line but I can't seem to get it to link.

    Here is the makefile:

    # use pkg-config for getting CFLAGS abd LDFLAGS
FFMPEG_LIBS=libavdevice libavformat libavfilter libavcodec libswscale libavutil
CFLAGS+=$(shell pkg-config  --cflags $(FFMPEG_LIBS))
LDFLAGS+=$(shell pkg-config --libs $(FFMPEG_LIBS))

EXAMPLES=decoding_encoding filtering metadata muxing

OBJS=$(addsuffix .o,$(EXAMPLES))

%: %.o
        $(CC) $< $(LDFLAGS) -o $@

%.o: %.c
        $(CC) $< $(CFLAGS) -c -o $@

.phony: all clean

all: $(OBJS) $(EXAMPLES)

clean:
        rm -rf $(EXAMPLES) $(OBJS)

    I can compile the source using this:

    gcc -Wall -I/usr/local/include -c -o decoding_encoding.o decoding_encoding.c

    When I try to link using this:

    gcc -Wall -L/usr/local/lib -lavdevice -lavformat -lavfilter -lavcodec -lswscale -lavutil -o decoding_encoding decoding_encoding.o

    At this point, I get a huge list of 'undefined reference error' 

    decoding_encoding.o: In function `audio_encode_example':
decoding_encoding.c:(.text+0x25): undefined reference to `avcodec_find_encoder'
decoding_encoding.c:(.text+0x6a): undefined reference to `avcodec_alloc_context3'
decoding_encoding.c:(.text+0xad): undefined reference to `avcodec_open'
decoding_encoding.c:(.text+0x1ce): undefined reference to `sin'
decoding_encoding.c:(.text+0x238): undefined reference to `avcodec_encode_audio'
decoding_encoding.c:(.text+0x297): undefined reference to `avcodec_close'
decoding_encoding.c:(.text+0x2a3): undefined reference to `av_free'
decoding_encoding.o: In function `audio_decode_example':
decoding_encoding.c:(.text+0x2f7): undefined reference to `av_init_packet'
decoding_encoding.c:(.text+0x30b): undefined reference to `avcodec_find_decoder'
decoding_encoding.c:(.text+0x359): undefined reference to `avcodec_alloc_context3'
decoding_encoding.c:(.text+0x379): undefined reference to `avcodec_open'
..... etc.
collect2: ld returned 1 exit status

    Am I doing something wrong with my linker command? I've examined the makefile and I believe that I'm doing exactly what the makefile is....or am I?

    Thanks,

    Leo

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