har0ke/FFmpeg
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

libfdk-aacdec: Flush delayed samples at the end

Browse Source 
The fdk-aac decoder can return decoded audio data with a delay.
(Whether it does this or not depends on the options set; by default
it does add some delay.) Previously, this delay was handled by
adjusting the timestamps of the decoded frames, but the last delayed
samples weren't returned.

Set the AV_CODEC_CAP_DELAY flag to indicate that the caller should
flush remaining samples at the end. Also trim off the corresponding
amount of samples at the start instead of adjusting timestamps.

Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2021-08-05 14:54:33 +03:00
parent 340a78afeb
commit c69b1a12bb
1 changed files with 65 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
libavcodec/libfdk-aacdec.c
View File

@ -58,7 +58,11 @@ typedef struct FDKAACDecContext {
int drc_cut;
int album_mode;
int level_limit;
int output_delay;
#if FDKDEC_VER_AT_LEAST(2, 5) // 2.5.10
int output_delay_set;
int flush_samples;
int delay_samples;
#endif
} FDKAACDecContext;
@ -123,7 +127,12 @@ static int get_stream_info(AVCodecContext *avctx)
avctx->sample_rate = info->sampleRate;
avctx->frame_size = info->frameSize;
#if FDKDEC_VER_AT_LEAST(2, 5) // 2.5.10
s->output_delay = info->outputDelay;
if (!s->output_delay_set && info->outputDelay) {
// Set this only once.
s->flush_samples = info->outputDelay;
s->delay_samples = info->outputDelay;
s->output_delay_set = 1;
}
#endif
for (i = 0; i < info->numChannels; i++) {
@ -367,14 +376,31 @@ static int fdk_aac_decode_frame(AVCodecContext *avctx, void *data,
int ret;
AAC_DECODER_ERROR err;
UINT valid = avpkt->size;
UINT flags = 0;
int input_offset = 0;
err = aacDecoder_Fill(s->handle, &avpkt->data, &avpkt->size, &valid);
if (err != AAC_DEC_OK) {
av_log(avctx, AV_LOG_ERROR, "aacDecoder_Fill() failed: %x\n", err);
return AVERROR_INVALIDDATA;
if (avpkt->size) {
err = aacDecoder_Fill(s->handle, &avpkt->data, &avpkt->size, &valid);
if (err != AAC_DEC_OK) {
av_log(avctx, AV_LOG_ERROR, "aacDecoder_Fill() failed: %x\n", err);
return AVERROR_INVALIDDATA;
}
} else {
#if FDKDEC_VER_AT_LEAST(2, 5) // 2.5.10
/* Handle decoder draining */
if (s->flush_samples > 0) {
flags |= AACDEC_FLUSH;
} else {
return AVERROR_EOF;
}
#else
return AVERROR_EOF;
#endif
}
err = aacDecoder_DecodeFrame(s->handle, (INT_PCM *) s->decoder_buffer, s->decoder_buffer_size / sizeof(INT_PCM), 0);
err = aacDecoder_DecodeFrame(s->handle, (INT_PCM *) s->decoder_buffer,
s->decoder_buffer_size / sizeof(INT_PCM),
flags);
if (err == AAC_DEC_NOT_ENOUGH_BITS) {
ret = avpkt->size - valid;
goto end;
@ -390,16 +416,36 @@ static int fdk_aac_decode_frame(AVCodecContext *avctx, void *data,
goto end;
frame->nb_samples = avctx->frame_size;
#if FDKDEC_VER_AT_LEAST(2, 5) // 2.5.10
if (flags & AACDEC_FLUSH) {
// Only return the right amount of samples at the end; if calling the
// decoder with AACDEC_FLUSH, it will keep returning frames indefinitely.
frame->nb_samples = FFMIN(s->flush_samples, frame->nb_samples);
av_log(s, AV_LOG_DEBUG, "Returning %d/%d delayed samples.\n",
frame->nb_samples, s->flush_samples);
s->flush_samples -= frame->nb_samples;
} else {
// Trim off samples from the start to compensate for extra decoder
// delay. We could also just adjust the pts, but this avoids
// including the extra samples in the output altogether.
if (s->delay_samples) {
int drop_samples = FFMIN(s->delay_samples, frame->nb_samples);
av_log(s, AV_LOG_DEBUG, "Dropping %d/%d delayed samples.\n",
drop_samples, s->delay_samples);
s->delay_samples -= drop_samples;
frame->nb_samples -= drop_samples;
input_offset = drop_samples * avctx->channels;
if (frame->nb_samples <= 0)
return 0;
}
}
#endif
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
goto end;
if (frame->pts != AV_NOPTS_VALUE)
frame->pts -= av_rescale_q(s->output_delay,
(AVRational){1, avctx->sample_rate},
avctx->time_base);
memcpy(frame->extended_data[0], s->decoder_buffer,
avctx->channels * avctx->frame_size *
memcpy(frame->extended_data[0], s->decoder_buffer + input_offset,
avctx->channels * frame->nb_samples *
av_get_bytes_per_sample(avctx->sample_fmt));
*got_frame_ptr = 1;
@ -432,7 +478,11 @@ const AVCodec ff_libfdk_aac_decoder = {
.decode = fdk_aac_decode_frame,
.close = fdk_aac_decode_close,
.flush = fdk_aac_decode_flush,
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF
#if FDKDEC_VER_AT_LEAST(2, 5) // 2.5.10
| AV_CODEC_CAP_DELAY
#endif
,
.priv_class = &fdk_aac_dec_class,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,