From 2f6bc4e76e2cd52262a2b28b7fb7857c609f8003 Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Fri, 6 Aug 2010 23:15:27 +0000 Subject: Apply misc fixes spotted by Diego to indevs.texi and outdevs.texi. Originally committed as revision 24724 to svn://svn.ffmpeg.org/ffmpeg/trunk --- doc/indevs.texi | 61 ++++++++++++++++++++++++++++----------------------------- 1 file changed, 30 insertions(+), 31 deletions(-) (limited to 'doc/indevs.texi') diff --git a/doc/indevs.texi b/doc/indevs.texi index cf29c4c306..b77d9d2084 100644 --- a/doc/indevs.texi +++ b/doc/indevs.texi @@ -5,8 +5,8 @@ Input devices are configured elements in FFmpeg which allow to access the data coming from a multimedia device attached to your system. When you configure your FFmpeg build, all the supported input devices -are enabled by default. You can list them using the configure option -"--list-indevs". +are enabled by default. You can list all available ones using the +configure option "--list-indevs". You can disable all the input devices using the configure option "--disable-indevs", and selectively enable an input device using the @@ -25,7 +25,7 @@ ALSA (Advanced Linux Sound Architecture) input device. To enable this input device during configuration you need libasound installed on your system. -This device allows to capture from an ALSA device. The name of the +This device allows capturing from an ALSA device. The name of the device to capture has to be an ALSA card identifier. An ALSA identifier has the syntax: @@ -42,7 +42,7 @@ specify card number or identifier, device number and subdevice number To see the list of cards currently recognized by your system check the files @file{/proc/asound/cards} and @file{/proc/asound/devices}. -For example to capture with @file{ffmpeg} from an alsa device with +For example to capture with @file{ffmpeg} from an ALSA device with card id 0, you may run the command: @example ffmpeg -f alsa -i hw:0 alsaout.wav @@ -65,38 +65,38 @@ Linux DV 1394 input device. @section jack -Jack input device. +JACK input device. To enable this input device during configuration you need libjack installed on your system. -A jack input device creates one or more jack writable clients, one for +A JACK input device creates one or more JACK writable clients, one for each audio channel, with name @var{client_name}:input_@var{N}, where @var{client_name} is the name provided by the application, and @var{N} is a number which identifies the channel. Each writable client will send the acquired data to the FFmpeg input device. -Once you have created one or more jack readable clients, you need to -connect them to one or more jack writable clients. +Once you have created one or more JACK readable clients, you need to +connect them to one or more JACK writable clients. -To connect or disconnect jack clients you can use the +To connect or disconnect JACK clients you can use the @file{jack_connect} and @file{jack_disconnect} programs, or do it through a graphical interface, for example with @file{qjackctl}. -To list the jack clients and their properties you can invoke the command +To list the JACK clients and their properties you can invoke the command @file{jack_lsp}. -Follows an example which shows how to capture a jack readable client +Follows an example which shows how to capture a JACK readable client with @file{ffmpeg}. @example -# create a jack writable client with name "ffmpeg" +# Create a JACK writable client with name "ffmpeg". $ ffmpeg -f jack -i ffmpeg -y out.wav -# start the sample jack_metro readable client +# Start the sample jack_metro readable client. $ jack_metro -b 120 -d 0.2 -f 4000 -# list the current jack clients +# List the current JACK clients. $ jack_lsp -c system:capture_1 system:capture_2 @@ -105,7 +105,7 @@ system:playback_2 ffmpeg:input_1 metro:120_bpm -# connect metro to the ffmpeg writable client +# Connect metro to the ffmpeg writable client. $ jack_connect metro:120_bpm ffmpeg:input_1 @end example @@ -122,9 +122,9 @@ Open Sound System input device. The filename to provide to the input device is the device node representing the OSS input device, and is usually set to -@file{/dev/dsp/}. +@file{/dev/dsp}. -For example to grab from @file{/dev/dsp/} using @file{ffmpeg} use the +For example to grab from @file{/dev/dsp} using @file{ffmpeg} use the command: @example ffmpeg -f oss -i /dev/dsp /tmp/oss.wav @@ -139,14 +139,14 @@ Video4Linux and Video4Linux2 input video devices. The name of the device to grab is a file device node, usually Linux systems tend to automatically create such nodes when the device -(e.g. an USB webcam) is plugged to the system, and has a name of the +(e.g. an USB webcam) is plugged into the system, and has a name of the kind @file{/dev/video@var{N}}, where @var{N} is a number associated to the device. Video4Linux and Video4Linux2 devices only support a limited set of @var{width}x@var{height} sizes and framerates. You can check which are -supported for example using the command @file{dov4l} for Video4Linux -devices, and the command @file{v4l-info} for Video4Linux2 devices. +supported for example with the command @file{dov4l} for Video4Linux +devices and the command @file{v4l-info} for Video4Linux2 devices. If the size for the device is set to 0x0, the input device will try to autodetect the size to use. @@ -157,19 +157,19 @@ dropped in later versions. Follow some usage examples of the video4linux devices with the ff* tools. @example -# grab and show the input of a video4linux device +# Grab and show the input of a video4linux device. ffplay -s 320x240 -f video4linux /dev/video0 -# grab and show the input of a video4linux2 device, autoadjust size +# Grab and show the input of a video4linux2 device, autoadjust size. ffplay -f video4linux2 /dev/video0 -# grab and record the input of a video4linux2 device, autoadjust size +# Grab and record the input of a video4linux2 device, autoadjust size. ffmpeg -f video4linux2 -i /dev/video0 out.mpeg @end example @section vfwcap -VFW (Video For Window) catpure input device. +VFW (Video For Windows) capture input device. @section x11grab @@ -177,31 +177,30 @@ X11 video input device. This device allows to capture a region of an X11 display. -The filename passed in input has the syntax: +The filename passed as input has the syntax: @example [@var{hostname}]:@var{display_number}.@var{screen_number}[+@var{x_offset},@var{y_offset}] @end example @var{hostname}:@var{display_number}.@var{screen_number} specifies the -X11 display name of the screen to grab from. @var{hostname} can be not -specified, and defaults to "localhost". The environment variable +X11 display name of the screen to grab from. @var{hostname} can be +ommitted, and defaults to "localhost". The environment variable @env{DISPLAY} contains the default display name. @var{x_offset} and @var{y_offset} specify the offsets of the grabbed -area with respect to the top/left border of the X11 screen image. They +area with respect to the top-left border of the X11 screen. They default to 0. Check the X11 documentation (e.g. man X) for more detailed information. Use the @file{dpyinfo} program for getting basic information about the -properties of your X11 display screen (e.g. grep for "name" or -"dimensions"). +properties of your X11 display (e.g. grep for "name" or "dimensions"). For example to grab from @file{:0.0} using @file{ffmpeg}: @example ffmpeg -f x11grab -r 25 -s cif -i :0.0 out.mpg -# grab at position 10,20 +# Grab at position 10,20. ffmpeg -f x11grab -25 -s cif -i :0.0+10,20 out.mpg @end example -- cgit v1.2.3