On 2/12/16, Moritz Barsnick <barsn...@gmx.net> wrote: > On Thu, Feb 11, 2016 at 17:19:47 -0700, Grant Curtis wrote: >> I'm working with a Speech-to-text service that wants audio files that are >> exactly 160kb large, which means 80,000 16-bit samples > > Which makes this uncompressed "raw audio", basically. > >> So far I've converted my video stream into an audio file with a sampling >> rate of 16,000 and converted it to s16le. Now I just have to grab 80,000 >> samples out of it. >> Is there any way to do that? Or perhaps I need to begin with a source file >> in a specific bitrate so that the math lines up? > > 16000 samples per second, a total of 80000 samples, that makes exactly > five seconds, right? Regardless of your input, it should be no issue > telling ffmpeg this length: "-t 5". > > On the other hand, you don't mention the word "segment" in your text, > just in the subject. Do you want to take an input file of arbitrary > length, and split it into segments of exactly five seconds each? You > should probably have a look at the segment muxer then: > https://www.ffmpeg.org/ffmpeg-formats.html#segment_002c-stream_005fsegment_002c-ssegment > > I fail to get constant length output there though. Hmmm. I have no idea > why. With videos and keyframes and the likes, I understand the issue. > Not here. > $ ffmpeg -t 35 -f lavfi -i anoisesrc -map 0:a -c:a pcm_s16le -ac 1 -ar 16000 > -f segment -segment_time 5 -segment_format s16le out.%03d.raw
ffmpeg -f lavfi -i anoisesrc=sample_rate=16000:duration=35:nb_samples=16000 -map 0:a -c:a pcm_s16le -ac 1 -f segment -segment_time 5 -segment_format s16le out.%03d.raw You can't resample after, you will get different number of samples per packet. _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
