I have been working on a program which needs to do audio resampling, and used
muxing.c as a base but now i am coming up against a problem.
Changing muxing.c so that the sound produced by the routine get_audio_frame is
not the same audio rate as the output causes an assert in the write_audio_frame
routine, normally the program prodces the same audio rate that the output
format is going to use, so the resampler really does nothing.
Modifying the audio tmp_frame definition and the associated tables for the
resampler was easy but i have 1 thing which im struggling to understand
line 310 muxing.c
if (frame) {
/* convert samples from native format to destination codec format,
using the resampler */
/* compute destination number of samples */
dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx,
c->sample_rate) + frame->nb_samples,
c->sample_rate,
c->sample_rate, AV_ROUND_UP);
av_assert0(dst_nb_samples == frame->nb_samples);
line 335 muxing.c
frame->pts = av_rescale_q(ost->samples_count, (AVRational){1,
c->sample_rate}, c->time_base);
As the current code stands the input and output sample_rate is the same, so
this code really does nothing, but now i have it so that the output is 44100
and the input is 48000, this code needs changing, my initial thought was this
will use the output sample rate, but i still get the assert
Can someone who knows more about this fix the demo so that the input sample
rate != output sample rate
joolz
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