On 1/14/18 8:38 PM, Liu Steven wrote: > >> 在 2018年1月9日，下午5:54，Dixit, Vishwanath <vdi...@akamai.com> 写道： >> >> >> >> On 1/9/18 3:05 PM, 刘歧 wrote: >>>>>> >>>>> >>>>> >>>>> I cannot sure use -cc_stream_map_ccgroup option is ok, because the >>>>> ccgroup string is not standard, maybe it can be defined bu user. >>>>> Maybe two ways: >>>>> 1. use -cc_stream_map_ccgroup ? this way is defined the name by ffmpeg, >>>>> cannot modify. >>>>> 2. parse the closed captions group string by KeyValue way? maybe this is >>>>> better. >>>> >>>> Actually, these requirements have been already handled. The parsing is >>>> happening based on key value pairs. The keys are ‘ccgroup’, ‘instreamid’, >>>> ‘language’. The values for these keys can be set after ‘:’ as given the >>>> examples in the patch. >>>> I am assuming you are trying to set ccgroup name as closecgroup. In that >>>> case, please modify the command as below. Because, the string ‘ccgroup’ is >>>> a key value, whatever string that comes after ‘ccgroup:’ is the cc group >>>> name. >>>> ./ffmpeg -re -f lavfi -i color=red -g 25 -b:v 1000k -b:a 64k -a53cc 1 -f >>>> hls -cc_stream_map "ccgroup:closecgroup,instreamid:CC1,language:en" >>>> -master_pl_name master.m3u8 live/out.m3u8 >>>> >>>> To clarify further, consider user wants to set cc group name as >>>> ‘mycaptions’, instream id as ‘SERVICE60’ language as Spanish, in that >>>> case, the map string would be >>>> -cc_stream_map "ccgroup:mycaptions,instreamid:SERVICE60,language:sp” >>> I understand and i got the point, >>> just one question, do you want force the user use ffmpeg must input a >>> string “ccgroup” ? if yes, maybe don’t let the user input it use string, >>> maybe use -cc_stream_map_ccgroup is better, What do you think about it? >> Are you suggesting to change the string from ‘–cc_stream_map’ to >> ‘-cc_stream_map_ccgroup’ and remove the ‘ccgroup’ key from the value string? >> Could you please clarify? >> >> Apart from this, I would like to highlight some advanced use cases where >> current implementation will be more meaningful. It is possible that that >> there could be multiple instream ids under the same closed caption group or >> there can be different closed captions groups. Example: >> -cc_stream_map "ccgroup:group1,instreamid:CC1,language:en >> ccgroup:group1,instreamid:CC2,language:sp” >> -cc_stream_map "ccgroup:eng_group,instreamid:CC1,language:en >> ccgroup:span_group,instreamid:CC1,language:sp” >> >> In these cases, the same ccgroup is mentioned in the –var_stream_map string >> as well. >> -var_stream_map "v:0,a:0,ccgroup:group1 v:1,a:1,ccgroup:group1" or >> -var_stream_map "v:0,a:0,ccgroup:eng_group v:1,a:1,ccgroup:span_group" >> >> Here, ‘ccgroup’ is a common key between –cc_stream_map and –var_stream_map. >> So, it is better to keep this key so that it will more readable and easily >> configurable for the user. > > Hi Dixit, > > I cannot found “ccgroup” string in rfc8216, or dose it in some other > specifications? Or user MUST use “ccgroup” in the var_stream_map? Hi Steven,
The string “ccgroup” is defined by me in both ‘var_stream_map’ and ‘cc_stream_map’ just for convenience. In the list of key value attribute pairs that I have defined, “ccgroup” is a key to which user can set a GROUP-ID (as defined in section 4.3.4.1. EXT-X-MEDIA of the RFC) for the closed captions group. This is a mandatory attribute in ‘cc_stream_map’ and optional attribute in ‘var_stream_map’. Regards, Vishwanath >> >>> >>> >>> Thanks >>> >>> Steven >>> _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
