Steve wrote > > Steve wrote >> I'm using ffmpeg audio decoding to create a gapless audio loop. I call >> av_seek_frame (with AVSEEK_FLAG_BACKWARD) to seek to my desired time, and >> call avcode_flush_buffers after. It seems the first decoded frame in the >> audio stream after the seek contains a few samples of silence or near >> silence, thus making the loop not gapless. >> >> If I skip an arbitrary amount of samples, the gap disappears. I've tried >> bypassing any swr_convert resampling with same results and also using the >> deprecated avcodec_decode_audio4 instead of the >> avcodec_send_packet/av_read_frame scheme. >> >> Is there a way to know how many samples I need to skip so I exactly hit >> the >> actual audio data, or prevent ffmpeg from having these filler samples in >> AVFrame->data after the seek? > I should also mention I know that the av_seek_frame won't seek to the > exact time requested, it's on the packet boundary. I can account for the > number of samples I need to skip to get to the exact time, but when the > number of samples is low (or I try without skipping these samples), the > problem of the silence samples is evident. > > This is using the mp3 decoder.
Incidentally this is ONLY happening with mp3 decoder (the most popular format!). The other decoders like aac, wma, flac don't have this silence gap. I guess it's some sort of bug. -- View this message in context: http://libav-users.943685.n4.nabble.com/Libav-user-Samples-of-silence-after-a-av-seek-frame-tp4662617p4662619.html Sent from the libav-users mailing list archive at Nabble.com. _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
