[FFmpeg-devel] [PATCH] This fixes ISO date formatissue when manifest created by this muxer is not playable in most players. This ensures compatibility with dash standard. Tested on many players (dashj.js, shaka, VLC, etc.)

[MFojtak]

Currently this muxer does not work at all. I don't know if 000Z would make 
it compatible with more player as I don't know any. However, adding Z makes 
it compatible with most popular ones like dash.js and shaka. Having this 
muxer working properly would bring more attention to it and maybe in the 
future somebody tests it with more players. But for now I suggest to roll 
out the change and "unblock" this muxer for some real wold use. Also, it 
would be great to make this muxer codec and container agnostic as it works 
with h264 and mp4 only. But again, nobody would bother if the muxer doesn't 
work at all with browsers. 
 ---------- Původní e-mail ----------
Od: Aaron Levinson <alevinsn at aracnet.com>
Komu: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
Datum: 30. 4. 2017 20:47:59
Předmět: Re: [FFmpeg-devel] [PATCH] This fixes ISO date formatissue when 
manifest created by this muxer is not playable in most players. This ensures
compatibility with dash standard. Tested on many players (dashj.js, shaka, 
VLC, etc.) 
"On 4/26/2017 4:27 AM, mfojtak wrote: 
> --- 
> libavformat/dashenc.c | 2 +- 
> 1 file changed, 1 insertion(+), 1 deletion(-) 
> 
> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c 
> index 6232c70..fe1d6c2 100644 
> --- a/libavformat/dashenc.c 
> +++ b/libavformat/dashenc.c 
> @@ -433,7 +433,7 @@ static void format_date_now(char *buf, int size) 
> struct tm *ptm, tmbuf; 
> ptm = gmtime_r(&t, &tmbuf); 
> if (ptm) { 
> - if (!strftime(buf, size, "%Y-%m-%dT%H:%M:%S", ptm)) 
> + if (!strftime(buf, size, "%Y-%m-%dT%H:%M:%SZ", ptm)) 
> buf[0] = '\0'; 
> } 
> } 
> 

This change appears to be correct. I wasn't previously knowledgeable 
about the 'Z' suffix, but I looked into it and it is documented in ISO 
8601 (https://en.wikipedia.org/wiki/ISO_8601 and also 
http://www.ecma-international.org/ecma-262/5.1/#sec-15.9.1.15 ). 

On a separate note, the actual format is: YYYY-MM-DDTHH:mm:ss.sssZ . 
The ".sss" part is missing from this implementation, which represents 
milliseconds. According to the specification, ".sss" may be absent, but 
maybe it would work with even more players if it were included. 
Technically, the specification states that an absent time-zone offset 
should be treated as 'Z', which indicates that the code was already 
compliant without the 'Z', even if it didn't work with most players. 
strftime() doesn't handle milliseconds, but perhaps it ought to populate 
milliseconds anyway as follows: 

if (!strftime(buf, size, "%Y-%m-%dT%H:%M:%S.000Z", ptm)) 

Aaron Levinson 
"