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ad_spdif: recreate spdif muxer on reset #18241

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Merged
kasper93 merged 2 commits into from
Jul 29, 2026
+98 −18
Merged

ad_spdif: recreate spdif muxer on reset #18241

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c6366eb
ad_spdif: recreate spdif muxer on reset
nathanlucas Jul 5, 2026
94f8640
ad_spdif: only warn for required codec parameters
nathanlucas Jul 26, 2026
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116 changes: 98 additions & 18 deletions audio/decode/ad_spdif.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@

#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libavutil/intreadwrite.h>
#include <libavutil/opt.h>

#include "audio/aframe.h"
Expand All @@ -37,6 +38,7 @@
#include "options/options.h"

#define OUTBUF_SIZE 65536
#define TRUEHD_MAJOR_SYNC_WARN_INTERVAL 6000

struct spdifContext {
struct mp_log *log;
Expand All @@ -48,6 +50,10 @@ struct spdifContext {
uint8_t out_buffer[OUTBUF_SIZE];
bool need_close;
bool use_dts_hd;
bool codec_params_probed;
int codec_profile;
int codec_rate;
unsigned int dropped_startup_packets;
struct mp_aframe *fmt;
int sstride;
struct mp_aframe_pool *pool;
Expand All @@ -74,24 +80,45 @@ static int write_packet(void *p, const uint8_t *buf, int buf_size)
return buf_size;
}

// (called on both filter destruction _and_ if lavf fails to init)
static void ad_spdif_destroy(struct mp_filter *da)
static void close_lavf_context(struct spdifContext *spdif_ctx, bool write_trailer)
{
struct spdifContext *spdif_ctx = da->priv;
AVFormatContext *lavf_ctx = spdif_ctx->lavf_ctx;
AVFormatContext *lavf_ctx = spdif_ctx->lavf_ctx;

if (lavf_ctx) {
if (spdif_ctx->need_close)
if (write_trailer && spdif_ctx->need_close)
av_write_trailer(lavf_ctx);
if (lavf_ctx->pb)
av_freep(&lavf_ctx->pb->buffer);
avio_context_free(&lavf_ctx->pb);
avformat_free_context(lavf_ctx);
spdif_ctx->lavf_ctx = NULL;
}
spdif_ctx->need_close = false;
TA_FREEP(&spdif_ctx->fmt);
}

// (called on both filter destruction _and_ if lavf fails to init)
static void ad_spdif_destroy(struct mp_filter *da)
{
struct spdifContext *spdif_ctx = da->priv;

close_lavf_context(spdif_ctx, true);
mp_free_av_packet(&spdif_ctx->avpkt);
}

static void ad_spdif_reset(struct mp_filter *da)
{
struct spdifContext *spdif_ctx = da->priv;

close_lavf_context(spdif_ctx, false);
spdif_ctx->dropped_startup_packets = 0;
}

static bool truehd_has_major_sync(const AVPacket *pkt)
{
return pkt->size >= 8 && AV_RB32(pkt->data + 4) == 0xf8726fba;
}

static void determine_codec_params(struct mp_filter *da, AVPacket *pkt,
int *out_profile, int *out_rate)
{
Expand Down Expand Up @@ -160,9 +187,32 @@ static void determine_codec_params(struct mp_filter *da, AVPacket *pkt,
done:
av_frame_free(&frame);
avcodec_free_context(&ctx);
}

if (profile == AV_PROFILE_UNKNOWN)
MP_WARN(da, "Failed to parse codec profile.\n");
static bool dts_profile_maybe_hd(int profile)
{
return profile == AV_PROFILE_DTS_HD_HRA ||
profile == AV_PROFILE_DTS_HD_MA ||
profile == AV_PROFILE_DTS_HD_MA_X ||
profile == AV_PROFILE_DTS_HD_MA_X_IMAX ||
profile == AV_PROFILE_UNKNOWN;
}

// Some codecs do not need every probed value for spdif muxer setup.
static bool codec_params_warning_needed(struct spdifContext *spdif_ctx,
int profile, int rate)
{
switch (spdif_ctx->codec_id) {
case AV_CODEC_ID_DTS:
if (spdif_ctx->use_dts_hd && dts_profile_maybe_hd(profile))
return profile == AV_PROFILE_UNKNOWN;

return rate <= 0;
case AV_CODEC_ID_AC3:
return rate <= 0;
default:
return false;
}
}

static int init_filter(struct mp_filter *da)
Expand All @@ -171,10 +221,20 @@ static int init_filter(struct mp_filter *da)

AVPacket *pkt = spdif_ctx->avpkt;

int profile = AV_PROFILE_UNKNOWN;
int c_rate = 0;
determine_codec_params(da, pkt, &profile, &c_rate);
MP_VERBOSE(da, "In: profile=%d samplerate=%d\n", profile, c_rate);
if (!spdif_ctx->codec_params_probed) {
spdif_ctx->codec_profile = AV_PROFILE_UNKNOWN;
determine_codec_params(da, pkt, &spdif_ctx->codec_profile,
&spdif_ctx->codec_rate);
spdif_ctx->codec_params_probed = true;
MP_VERBOSE(da, "In: profile=%d samplerate=%d\n",
spdif_ctx->codec_profile, spdif_ctx->codec_rate);
if (codec_params_warning_needed(spdif_ctx, spdif_ctx->codec_profile,
spdif_ctx->codec_rate))
MP_WARN(da, "Failed to parse codec parameters.\n");
}

int profile = spdif_ctx->codec_profile;
int c_rate = spdif_ctx->codec_rate;

AVFormatContext *lavf_ctx = avformat_alloc_context();
if (!lavf_ctx)
Expand Down Expand Up @@ -225,19 +285,13 @@ static int init_filter(struct mp_filter *da)
num_channels = 2;
break;
case AV_CODEC_ID_DTS: {
bool is_hd = profile == AV_PROFILE_DTS_HD_HRA ||
profile == AV_PROFILE_DTS_HD_MA ||
profile == AV_PROFILE_DTS_HD_MA_X ||
profile == AV_PROFILE_DTS_HD_MA_X_IMAX ||
profile == AV_PROFILE_UNKNOWN;

// Apparently, DTS-HD over SPDIF is specified to be 7.1 (8 channels)
// for DTS-HD MA, and stereo (2 channels) for DTS-HD HRA. The bit
// streaming rate as well as the signaled channel count are defined
// based on this value.
int dts_hd_spdif_channel_count = profile == AV_PROFILE_DTS_HD_HRA ?
2 : 8;
if (spdif_ctx->use_dts_hd && is_hd) {
if (spdif_ctx->use_dts_hd && dts_profile_maybe_hd(profile)) {
av_dict_set_int(&format_opts, "dtshd_rate",
dts_hd_spdif_channel_count * 96000, 0);
sample_format = AF_FORMAT_S_DTSHD;
Expand Down Expand Up @@ -318,6 +372,7 @@ static void ad_spdif_process(struct mp_filter *da)
struct demux_packet *mpkt = inframe.data;
struct mp_aframe *out = NULL;
double pts = mpkt->pts;
bool drop_packet = false;

if (!spdif_ctx->avpkt) {
spdif_ctx->avpkt = av_packet_alloc();
Expand All @@ -326,6 +381,22 @@ static void ad_spdif_process(struct mp_filter *da)
mp_set_av_packet(spdif_ctx->avpkt, mpkt, NULL);
spdif_ctx->avpkt->pts = spdif_ctx->avpkt->dts = 0;
if (!spdif_ctx->lavf_ctx) {
// A fresh TrueHD spdif muxer needs a major sync to initialize its
// stream parameters, so wait for major sync before initializing.
if (spdif_ctx->codec_id == AV_CODEC_ID_TRUEHD &&
!truehd_has_major_sync(spdif_ctx->avpkt))
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kasper93 marked this conversation as resolved.
{
spdif_ctx->dropped_startup_packets++;
if (spdif_ctx->dropped_startup_packets %
TRUEHD_MAJOR_SYNC_WARN_INTERVAL == 0)
{
MP_WARN(da, "Still waiting for TrueHD major sync after "
"dropping %u packets.\n",
spdif_ctx->dropped_startup_packets);
}
drop_packet = true;
goto done;

@kasper93 kasper93 Jul 28, 2026

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I would add here MP_WARN after every N packets, in case we lock ourselves in the infinite loop. It can be big number, so it only is printed when something bad happens.

@nathanlucas nathanlucas Jul 29, 2026

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Done. The interval is 6000 packets, which would be 5 seconds if the stream contained the expected 1200 truehd AU/s.

}
if (init_filter(da) < 0)
goto done;
mp_assert(spdif_ctx->avpkt);
Expand All @@ -339,6 +410,12 @@ static void ad_spdif_process(struct mp_filter *da)
MP_ERR(da, "spdif mux error: '%s'\n", mp_strerror(AVUNERROR(ret)));
goto done;
}
if (spdif_ctx->dropped_startup_packets) {
MP_VERBOSE(da, "dropped %u TrueHD packet%s before major sync\n",
spdif_ctx->dropped_startup_packets,
spdif_ctx->dropped_startup_packets == 1 ? "" : "s");
spdif_ctx->dropped_startup_packets = 0;
}

out = mp_aframe_new_ref(spdif_ctx->fmt);
int samples = spdif_ctx->out_buffer_len / spdif_ctx->sstride;
Expand All @@ -360,6 +437,8 @@ static void ad_spdif_process(struct mp_filter *da)
talloc_free(mpkt);
if (out) {
mp_pin_in_write(da->ppins[1], MAKE_FRAME(MP_FRAME_AUDIO, out));
} else if (drop_packet) {
mp_filter_internal_mark_progress(da);
} else {
mp_filter_internal_mark_failed(da);
}
Expand Down Expand Up @@ -423,6 +502,7 @@ static const struct mp_filter_info ad_spdif_filter = {
.name = "ad_spdif",
.priv_size = sizeof(struct spdifContext),
.process = ad_spdif_process,
.reset = ad_spdif_reset,
.destroy = ad_spdif_destroy,
};

Expand Down
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