[FFmpeg-trac] #9329(avformat:new): HLS stream map with subtitles group results in error

[FFmpeg]

#9329: HLS stream map with subtitles group results in error
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             Reporter:  Yash      |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avformat  |                  Version:  git-master
             Keywords:  HLS       |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 Summary of the bug:

 I am creating an HLS stream with subtitles in two languages with the same
 subtitle group and the command results in an error.

 How to reproduce:
 {{{
 % ffmpeg -loglevel debug -vsync 0 -hwaccel cuvid -hwaccel_output_format
 cuda -c:v h264_cuvid -i transformers.mp4 -y -filter_complex
 "[0:v]hwdownload,format=nv12[0_v_cpu];[0_v_cpu]colorspace=irange=tv:range=tv:ispace=smpte170m:space=bt709:itrc=smpte170m:trc=bt709:iprimaries=smpte170m:primaries=bt709[init_processed];[init_processed]split=2[360p][720p];[360p]hwupload_cuda,scale_npp=640:360:interp_algo=lanczos[360pScaled];[720p]hwupload_cuda,scale_npp=1280:720:interp_algo=lanczos[720pScaled]"
 -max_muxing_queue_size 256 -hls_list_size 0 -hls_playlist_type vod
 -hls_flags single_file+independent_segments -hls_segment_type fmp4
 -hls_segment_filename %v.mp4 -hls_subtitle_path %v.vtt -hls_time 2
 -master_pl_name 1.m3u8 -preset:v slow -tune:v hq -qmin:v 0 -bf:v 3
 -b_ref_mode:v 2 -temporal_aq:v 1 -i_qfactor:v 0.75 -b_qfactor:v 1.1
 -color_primaries:v bt709 -color_trc:v bt709 -colorspace:v bt709
 -color_range:v tv -g:v 48 -keyint_min:v 48 -forced-idr:v 1 -map
 "[360pScaled]" -map "[720pScaled]" -map 0:a:0 -map 0:a:0 -map 0:s:0 -map
 0:s:1 -c:s:0 webvtt -c:s:1 webvtt -c:v:0 h264_nvenc -c:v:1 h264_nvenc
 -b:v:0 400k -b:v:1 3000k -maxrate:v:0 400k -maxrate:v:1 3000k -bufsize:v:0
 800k -bufsize:v:1 6000k -c:a:0 aac -c:a:1 aac -b:a:0 96k -b:a:1 128k
 -var_stream_map
 "v:0,agroup:audio_96k,sgroup:subtitle,name:60ed13d04c18991fa348e35c_0
 v:1,agroup:audio_128k,sgroup:subtitle,name:60ed13d04c18991fa348e35c_1
 a:0,agroup:audio_96k,name:60ed13d04c18991fa348e35c_en_96k,language:en
 a:1,agroup:audio_128k,name:60ed13d04c18991fa348e35c_en_128k,language:en
 s:0,sgroup:subtitle,name:eng,language:eng
 s:1,sgroup:subtitle,name:ara,language:ara" -f hls %v.m3u8
 ffmpeg version 4.4.git
 built on ...
 Ubuntu 20.04 5.8.0-50-generic
 CUDA 11.1
 Video Codec SDK version 11.0.10.
 NVIDIA Driver Version: 460.73.01
 }}}

 Error
 {{{
 [mp4 @ 0x55d28332d040] No streams to mux were specified
 Could not write header for output file #0 (incorrect codec parameters ?):
 Invalid argument
 Error initializing output stream 0:1 --
 }}}

 Full Error (debug) log and video file are in attachments.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9329>
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