I had the need to generate a breakdown slide with a static image for the video and an audio track. This needed to be a video file, specifically a Transport Stream. The command below generates a TS video clip which has the duration of the supplied audio file.

ffmpeg -loop 1 -i IMAGE.png -i AUDIO.flac -c:v libx264 -c:a aac -ar 48k -b:a 192k -pix_fmt yuv420p -shortest -streamid 0:100 -streamid 1:101 -mpegts_flags latm OUTPUT.ts

You will need to modify the command above to meet your needs - the PIDs to use along with codecs, bitrates etc. Below explains what each flag is for:

• -loop 1 tells ffmpeg to loop the image for the duration of the clip
• -c:v libx264 specifies the video codec as x264
• -c:a aac specifies the audio codec as AAC
• -ar 48k sets the audio samle rate
• -b:a 192k sets the audio bitrate
• -pix_fmt yuv420p sets the pixel format
• -sortest tells ffmpeg to make the clip the length of the audio file (without this the clip would have infinte length, because of the looping of the image file)
• -streamid 0:100 tells ffmpeg to set the PID of the first stream (video/image in this case, because it was specified first) to 100
• -streamid 1:101 tells ffmpeg to set the PID fo the second stream (audio) to 101
• -mpegtf_flags latm tells ffmpeg to use LATM packetisation for AAC streams