Html 5 video/audio 格式转换 ogg
Html5 开始支持video和audio标签，但是各个浏览器支持的格式不一样，见下图
| Browser | Ogg Vorbis | MP3 | WAV |
|---|---|---|---|
| FireFox 3.6+ | ✓ | ✓ | |
| Safari 5+ | ✓ | ✓ | |
| Chrome 6 | ✓ | ✓ | |
| Opera 10.5+ | ✓ | ✓ | |
| Internet Explorer 9 (beta) | ✓ | ✓ |
因此，要想全面兼容，至少需要提供两种格式，由于wav文件体积太庞大，因此我们提供MP3和ogg
MP3转换很容易，下面简单说下ogg
Ogg全称应该是OGGVobis(oggVorbis)是一种新的音频压缩格式，类似于MP3等的音乐格式。Ogg是完全免费、开放和没有专利限制的。OggVorbis文件的扩展名是.OGG。Ogg文件格式可以不断地进行大小和音质的改良，而不影响旧有的编码器或播放器。
ogg编码转换有个开源项目可以通过ffmpeg2theor（http://v2v.cc/~j/ffmpeg2theora/index.html）来实现：
ffmpeg2theora 编码器，可以将任何格式的影音媒体档案，转换成 ogg 档案。作者以传统的 C 语言编写这套软件，主要是利用大量的数据结构和指标来编写程式，由于这个编码器是采用命令列的操作模式，对于不熟悉命令列接口的人来说较为不便。
下面是 ffmpeg2theora 的使用说明：
ffmpeg2theora 0.27 - Xiph.Org libtheora 1.1 20090822 (Thusnelda)
Usage: ffmpeg2theora [options] input
General output options:
-o, --output alternative output filename
--no-skeleton disables ogg skeleton metadata output
--skeleton-3 outputs Skeleton Version 3, without keyframe indexes
-s, --starttime start encoding at this time (in sec.)
-e, --endtime end encoding at this time (in sec.)
-p, --preset encode file with preset.
Right now there is preview, pro and videobin. Run
'ffmpeg2theora -p info' for more informations
Video output options:
-v, --videoquality [0 to 10] encoding quality for video (default: 6)
use higher values for better quality
-V, --videobitrate encoding bitrate for video (kb/s)
--soft-target Use a large reservoir and treat the rate
as a soft target; rate control is less
strict but resulting quality is usually
higher/smoother overall. Soft target also
allows an optional -v setting to specify
a minimum allowed quality.
--two-pass Compress input using two-pass rate control
This option requires that the input to the
to the encoder is seekable and performs
both passes automatically.
--first-pass <filename> Perform first-pass of a two-pass rate
controlled encoding, saving pass data to
<filename> for a later second pass
--second-pass <filename> Perform second-pass of a two-pass rate
controlled encoding, reading first-pass
data from <filename>. The first pass
data must come from a first encoding pass
using identical input video to work
properly.
--optimize optimize video output filesize (slower)
(same as speedlevel 0)
--speedlevel encoding is faster with higher values
the cost is quality and bandwidth
- 0: Slowest (best)
- 1: Enable early skip (default)
- 2: Disable motion compensation
-x, --width scale to given width (in pixels)
-y, --height scale to given height (in pixels)
--max_size scale output frame to be within box of
given size, height optional (%d[x%d], i.e. 640x480)
--aspect define frame aspect ratio: i.e. 4:3 or 16:9
--pixel-aspect define pixel aspect ratio: i.e. 1:1 or 4:3,
overwrites frame aspect ratio
-F, --framerate output framerate e.g 25:2 or 16
--croptop, --cropbottom, --cropleft, --cropright
crop input by given pixels before resizing
-K, --keyint [1 to 2147483647] keyframe interval (default: 64)
-d --buf-delay <n> Buffer delay (in frames). Longer delays
allow smoother rate adaptation and provide
better overall quality, but require more
client side buffering and add latency. The
default value is the keyframe interval for
one-pass encoding (or somewhat larger if
--soft-target is used) and infinite for
two-pass encoding. (only works in bitrate mode)
--no-upscaling only scale video or resample audio if input is
bigger than provided parameters
Video transfer options:
--pp Video Postprocessing, denoise, deblock, deinterlacer
use --pp help for a list of available filters.
-C, --contrast [0.1 to 10.0] contrast correction (default: 1.0)
Note: lower values make the video darker.
-B, --brightness [-1.0 to 1.0] brightness correction (default: 0.0)
Note: lower values make the video darker.
-G, --gamma [0.1 to 10.0] gamma correction (default: 1.0)
Note: lower values make the video darker.
-Z, --saturation [0.1 to 10.0] saturation correction (default: 1.0)
Note: lower values make the video grey.
Audio output options:
-a, --audioquality [-2 to 10] encoding quality for audio (default: 1)
use higher values for better quality
-A, --audiobitrate [32 to 500] encoding bitrate for audio (kb/s)
-c, --channels set number of output channels
-H, --samplerate set output samplerate (in Hz)
--noaudio disable audio from input
--novideo disable video from input
Input options:
--deinterlace force deinterlace, otherwise only material
marked as interlaced will be deinterlaced
-f, --format specify input format
--inputfps fps override input fps
--audiostream id by default the first audio stream is selected,
use this to select another audio stream
--videostream id by default the first video stream is selected,
use this to select another video stream
--nosync do not use A/V sync from input container.
try this if you have issues with A/V sync
Subtitles options:
--subtitles file use subtitles from the given file (SubRip (.srt) format)
--subtitles-encoding encoding set encoding of the subtitles file
supported are utf-8, utf8, iso-8859-1, latin1
--subtitles-language language set subtitles language (de, en_GB, etc)
--subtitles-category category set subtitles category (default "subtitles")
--subtitles-ignore-non-utf8 ignores any non UTF-8 sequence in UTF-8 text
--nosubtitles disables subtitles from input
(equivalent to --subtitles=none)
--subtitle-types=[all,text,spu,none] select what subtitle types to include from the
input video (default text)
Metadata options:
--artist Name of artist (director)
--title Title
--date Date
--location Location
--organization Name of organization (studio)
--copyright Copyright
--license License
--contact Contact link
--nometadata disables metadata from input
--no-oshash do not include oshash of source file(SOURCE_OSHASH)
Keyframe indexing options:
--index-interval <n> set minimum distance between indexed keyframes
to <n> ms (default: 2000)
--theora-index-reserve <n> reserve <n> bytes for theora keyframe index
--vorbis-index-reserve <n> reserve <n> bytes for vorbis keyframe index
--kate-index-reserve <n> reserve <n> bytes for kate keyframe index
Other options:
-P, --pid fname write the process' id to a file
-h, --help this message
--info output json info about input file, use -o to save json to file
--frontend print status information in json, one json dict per line
Examples:
ffmpeg2theora videoclip.avi (will write output to videoclip.ogv)
ffmpeg2theora videoclip.avi --subtitles subtitles.srt (same, with subtitles)
cat something.dv | ffmpeg2theora -f dv -o output.ogv -
Encode a series of images:
ffmpeg2theora frame%06d.png -o output.ogv
Live streaming from V4L Device:
ffmpeg2theora /dev/video0 -f video4linux --inputfps 15 -x 160 -y 128 -o - \
| oggfwd icast2server 8000 password /theora.ogv
(you might have to use video4linux2 depending on your hardware)
Live encoding from a DV camcorder (needs a fast machine):
dvgrab - | ffmpeg2theora -f dv -x 352 -y 288 -o output.ogv -
Live encoding and streaming to icecast server:
dvgrab --format raw - \
| ffmpeg2theora -f dv -x 160 -y 128 -o /dev/stdout - \
| oggfwd icast2server 8000 password /theora.ogv
示例：
G:\Users\Administrator>ffmpeg2theora-0.27.exe -o G:\Users\Administrator\Desktop\simplehtmldom_1_
11\simplehtmldom\test.ogg G:\Users\Administrator\Desktop\simplehtmldom_1_11\simp
lehtmldom\026d9859-dea9-4e4f-9c60-6545e51bf547.wav
Html示例
