static int prepare_audio_decoding( lsmash_handler_t *h, audio_option_t *opt )
{
avs_handler_t *hp = (avs_handler_t *)h->audio_private;
h->audio_pcm_sample_count = hp->vi->num_audio_samples;
/* Support of WAVEFORMATEXTENSIBLE is much restrictive on AviUtl, so we always use WAVEFORMATEX instead. */
WAVEFORMATEX *Format = &h->audio_format.Format;
Format->nChannels = hp->vi->nchannels;
Format->nSamplesPerSec = hp->vi->audio_samples_per_second;
Format->wBitsPerSample = avs_bytes_per_channel_sample( hp->vi ) * 8;
Format->nBlockAlign = avs_bytes_per_audio_sample( hp->vi );
Format->nAvgBytesPerSec = Format->nSamplesPerSec * Format->nBlockAlign;
Format->wFormatTag = WAVE_FORMAT_PCM;
Format->cbSize = 0;
return 0;
}
static int avisynth_read_packet_audio(AVFormatContext *s, AVPacket *pkt,
int discard)
{
AviSynthContext *avs = s->priv_data;
AVRational fps, samplerate;
int samples;
int64_t n;
const char *error;
if (avs->curr_sample >= avs->vi->num_audio_samples)
return AVERROR_EOF;
fps.num = avs->vi->fps_numerator;
fps.den = avs->vi->fps_denominator;
samplerate.num = avs->vi->audio_samples_per_second;
samplerate.den = 1;
if (avs_has_video(avs->vi)) {
if (avs->curr_frame < avs->vi->num_frames)
samples = av_rescale_q(avs->curr_frame, samplerate, fps) -
avs->curr_sample;
else
samples = av_rescale_q(1, samplerate, fps);
} else {
samples = 1000;
}
/* After seeking, audio may catch up with video. */
if (samples <= 0) {
pkt->size = 0;
pkt->data = NULL;
return 0;
}
if (avs->curr_sample + samples > avs->vi->num_audio_samples)
samples = avs->vi->num_audio_samples - avs->curr_sample;
/* This must happen even if the stream is discarded to prevent desync. */
n = avs->curr_sample;
avs->curr_sample += samples;
if (discard)
return 0;
pkt->size = avs_bytes_per_channel_sample(avs->vi) *
samples * avs->vi->nchannels;
if (!pkt->size)
return AVERROR_UNKNOWN;
if (av_new_packet(pkt, pkt->size) < 0)
return AVERROR(ENOMEM);
pkt->pts = n;
pkt->dts = n;
pkt->duration = samples;
pkt->stream_index = avs->curr_stream;
avs_library.avs_get_audio(avs->clip, pkt->data, n, samples);
error = avs_library.avs_clip_get_error(avs->clip);
if (error) {
av_log(s, AV_LOG_ERROR, "%s\n", error);
avs->error = 1;
av_packet_unref(pkt);
return AVERROR_UNKNOWN;
}
return 0;
}