I am looking for specifications for the ogg vorbis header packet format. I have searched the Internet without much success. Where can I find one?
http://en.wikipedia.org/wiki/Ogg#Page_structure describes what every single page in an ogg file looks like -- file metadata and stream data alike.
http://xiph.org/vorbis/doc/Vorbis_I_spec.html actually describes the contents of a ogg vorbis file's metadata (header) pages. The three header packets are:
an Identification Header,
a Comment Header, and
a Setup Header.
The specification requires that all three of these headers be present.
A bitfield diagram of the Ogg Vorbis identification header is at http://wiki.xiph.org/OggVorbis.
Hope this is what you're looking for:
http://xiph.org/vorbis/doc/v-comment.html
Related
As you can see the in the above image, the end part of the .wav file is not represented in the mp3 file. Here, I am making use of avcodec_decode_audio4() api to decode each packet, and using lame_encode_buffer() api to encode it in mp3 format. Here, I am seeing this issue for MONO streams( 1.wav -> 1.mp3 ). I just wanted to know why is this occuring, even when I am providing all the .wav file content. I am suspecting there is some caching that is happening, due to which I am unable to get whole data into the mp3 file. Any help here would be appreciated.
Add a section of silence at the end of the WAV file then reconvert to mp3
I am working on ffmpeg and x265 for video encoding. From the release note of x265:
HDR10+ supported. Dynamic metadata may be either supplied as a bitstream via the userSEI field of x265_picture, or as a json jile that can be parsed by x265 and inserted into the bitstream; use --dhdr10-info to specify json file name, and --dhdr10-opt to enable optimization of inserting tone-map information only at IDR frames, or when the tone map information changes.
But I dont know how to export the dynamic metadata from a video sequence as a userSEI or json file. Hope to get solution from you.
Anyone know if ffprobe is safe to use as a method to check the content of a video? I want to determine if someone renames an exe to mp4 or some other video mime and I run ffprobe on it, would the file execute or fail safely without executing the content?
ffprobe should not execute content unless DirectDraw filter would do it itself (which is rather weird thing to think of).
Yet, AFAIK, ffprobe doesnt't produce nice MIME information, especially for not-multimedia-files. format_name/format_long_name are not very good.
For what you're looking for, the best approach is content sniffing described at https://mimesniff.spec.whatwg.org/
I have found that link in this SO question: MIME type for transcoded stream
I need to do conformance tests of JPEG decoder. The streams available in ITUS are .j2k for jpeg2000 format. What is the standard used in .jpg format? How do they differ in structure? How can I view the J2k files?
JPEG 2000 is a completely different file format from JPEG (which is usually what .jpg files are). The Wikipedia article I linked gives a list of compatible software.
Where can I find documentation/sample code of the VOBsub subtitles format? The one that's an .idx and a .sub file.
I need to create a program that generates those subtitles. I've been looking on Google but only found how to rip them from DVD.
Thanks
VOBsub extracts the DVD subtitles raw PES from a DVD and dumps this to a .sub file. It also creates a .idx Index file with the times and byteoffsets for each and every single subtitle. The format has support for multiple tracks and can also be embedded in MP4 (by Nero) and Matroska files.
Technical specs vobsub
Technical specs from Matroska.org
Example files: Specs_and_idx-sub_files.rar
Have a look at these open source implementations:
BDSup2Sub (Java)
Subtitle Edit (C#)
guliverkli by gabest (C++) check out VSFilter and VSRip; original implementation
Son2VobSub.rar (C++)
And then there are the media players like VLC. You can also check out these threads on doom9:
http://forum.doom9.org/archive/index.php/t-87171.html
http://forum.doom9.org/archive/index.php/t-99815.html
I think your best approach would be to have a look at the sourcecode of some of the open-source media players. Some of them will have the code to interpret an .idx or .sub subtitle file.
This might be a useful starting point:
http://sourceforge.net/projects/guliverkli/