[FFmpeg-user] License Restrictions, Implementation Status in FFmpeg, and the General Availability of Implementations of Sony Camera Codecs, especially XAVC.

[Abyss]

Hello, FFmpeg users.

I want to carefully buy a digital camera for making videos. Sony makes 
good digital cameras at a good price (if rolling shutter is not a 
critical concern), but their cameras use the video codec XAVC S, 
sometimes exclusively (e.g. Alpha ZV-E10), and sometimes also the codec 
AVCHD (e.g. Alpha 6600). I use Debian 12 Gnu/Linux. I have access to a 
reasonably current Windows OS courtesy of the local public library. 
Whether or not the library Windows computers could be a means for 
converting from a Sony codec I do not know.

I have tried to find information on exactly out how well Sony camera 
video files using Sony codec XAVC will work with FFmpeg. I have found 
three tangential sources of information.

(1) From FFmpeg thread "[FFmpeg-devel] Patch to add avcintra-flavor 
option from x264", dated 06 Dec. 2018, 
https://ffmpeg.org/pipermail/ffmpeg-devel/2018-December/237252.html , I 
surmise there was a patch with option avcintra-flavor option for the 
codec H.264 as implemented by libx264.

(2) From FFmpeg thread "[FFmpeg-user] Convert to XAVC", dated 10 Jan. 
2022, http://ffmpeg.org/pipermail/ffmpeg-user/2022-January/054054.html , 
is the advice to 'check the x264 option "avcintra-flavor" with the value 
"sony".'.

My text search of manpage ffmpeg-all did not find 'sony' except as 
related to the Sony PlayStation and some other concerns unfamiliar to me 
and did not find either of 'XAVC' and 'avcintra-flavor'. I found 
'avcintra-class', which appears to be unrelated to Sony XAVC or AVCHD.

(3) From FFAStrans thread "XAVC-Intra UHD Class 480", 
https://www.ffastrans.com/frm/forum/viewtopic.php?t=1203 , someone 
wanted to convert to 'XAVC-intra Class 480 UHD'.

To further complicate matters, the English Wikipedia page "XAVC" says: 
"XAVC is a format that will be licensed to companies that want to make 
XAVC products." and that H.264/MPEG-4 AVC is the video standard that is 
used by XAVC. Sony itself says that 'The Sony XAVC format complies with 
H.264 level 5.2' in their "XAVC Specification Overview", revision 2.2, 
12 Sept. 2014.

H.264/AVC is patented by parties not Sony, widely supported, and 
supported by FFmpeg. I don't understand how Sony can extend H.264 and 
require a license. A basic explanation on how and what Sony is and is 
not licensing with respect to codec XAVC from someone already familiar 
with the issue would be welcome.

I am very glad that FFmpeg is available on Linux.

Thanks.

—Abyss