[FFmpeg-devel] [PATCH 05/10] spdifenc: IEC 61937 encapsulation of DTS-HD for HDMI
Anssi Hannula
anssi.hannula
Wed Dec 29 06:06:38 CET 2010
---
This time the default mode of operation is to passthrough DTS-core only
unless the HD mode is explicitely requested by the user via an AVOption
(this patch thus depends on the "Add AVOption support for muxers" patch).
This way we avoid exporting the final bitrate in avctx->bit_rate as I
previously planned, as now the caller always specifies the output rate
themselves and therefore already knows the output rate (as is the case
for other formats as well).
An AVOption is used instead of the previously planned muxrate as the
usage doesn't exactly match muxrate semantics.
This patch expects that the libav user who wants HD passthrough has
knowledge of the existence of a HD stream so that they can enable the HD
mode when needed. Providing such a method is discussed in "dca: export
profile information on decode" thread.
Changelog | 2 +-
libavformat/avformat.h | 2 +-
libavformat/spdifenc.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 149 insertions(+), 2 deletions(-)
diff --git a/Changelog b/Changelog
index 41ece6c..eac1b0e 100644
--- a/Changelog
+++ b/Changelog
@@ -55,7 +55,7 @@ version <next>:
- Win64 support for optimized asm functions
- MJPEG/AVI1 to JPEG/JFIF bitstream filter
- ASS subtitle encoder and decoder
-- IEC 61937 encapsulation for E-AC3 and TrueHD (for HDMI passthrough)
+- IEC 61937 encapsulation for E-AC3, TrueHD, DTS-HD (for HDMI passthrough)
- overlay filter added
- rename aspect filter to setdar, and pixelaspect to setsar
- IEC 61937 demuxer
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 9eab2da..56a1946 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -22,7 +22,7 @@
#define AVFORMAT_AVFORMAT_H
#define LIBAVFORMAT_VERSION_MAJOR 52
-#define LIBAVFORMAT_VERSION_MINOR 91
+#define LIBAVFORMAT_VERSION_MINOR 92
#define LIBAVFORMAT_VERSION_MICRO 0
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
diff --git a/libavformat/spdifenc.c b/libavformat/spdifenc.c
index c5bc72b..a2683b9 100644
--- a/libavformat/spdifenc.c
+++ b/libavformat/spdifenc.c
@@ -48,9 +48,12 @@
#include "spdif.h"
#include "libavcodec/ac3.h"
#include "libavcodec/dca.h"
+#include "libavcodec/dcadata.h"
#include "libavcodec/aacadtsdec.h"
+#include "libavutil/opt.h"
typedef struct IEC958Context {
+ const AVClass *av_class;
enum IEC958DataType data_type; ///< burst info - reference to type of payload of the data-burst
int length_code; ///< length code in bits or bytes, depending on data type
int pkt_offset; ///< data burst repetition period in bytes
@@ -68,11 +71,24 @@ typedef struct IEC958Context {
int hd_buf_count; ///< number of frames in the hd audio buffer
int hd_buf_filled; ///< amount of bytes in the hd audio buffer
+ int dtshd_skip; ///< counter used for skipping DTS-HD frames
+
+ /* AVOptions: */
+ int dtshd_rate;
+ int dtshd_fallback;
+
/// function, which generates codec dependent header information.
/// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
int (*header_info) (AVFormatContext *s, AVPacket *pkt);
} IEC958Context;
+static const AVOption options[] = {
+{ "dtshd_rate", "mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled)", offsetof(IEC958Context, dtshd_rate), FF_OPT_TYPE_INT, 0, 0, 768000, AV_OPT_FLAG_ENCODING_PARAM },
+{ "dtshd_fallback_time", "min secs to strip HD for after an overflow (-1: till the end)", offsetof(IEC958Context, dtshd_fallback), FF_OPT_TYPE_INT, 60, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
+{ NULL },
+};
+
+static const AVClass class = { "spdif", av_default_item_name, options, LIBAVUTIL_VERSION_INT };
static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)
{
@@ -115,15 +131,124 @@ static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)
return 0;
}
+/*
+ * DTS type IV (DTS-HD) can be transmitted with various frame repetition
+ * periods; longer repetition periods allow for longer packets and therefore
+ * higher bitrate. Longer repetition periods mean that the constant bitrate of
+ * the outputted IEC 61937 stream is higher.
+ * The repetition period is measured in IEC 60958 frames (4 bytes).
+ */
+enum {
+ DTS4_REP_PER_512 = 0x0,
+ DTS4_REP_PER_1024 = 0x1,
+ DTS4_REP_PER_2048 = 0x2,
+ DTS4_REP_PER_4096 = 0x3,
+ DTS4_REP_PER_8192 = 0x4,
+ DTS4_REP_PER_16384 = 0x5,
+};
+
+static int spdif_dts4_subtype(int period)
+{
+ switch (period) {
+ case 512: return DTS4_REP_PER_512;
+ case 1024: return DTS4_REP_PER_1024;
+ case 2048: return DTS4_REP_PER_2048;
+ case 4096: return DTS4_REP_PER_4096;
+ case 8192: return DTS4_REP_PER_8192;
+ case 16384: return DTS4_REP_PER_16384;
+ }
+ return -1;
+}
+
+static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
+ int sample_rate, int blocks)
+{
+ IEC958Context *ctx = s->priv_data;
+ const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
+ int pkt_size = pkt->size;
+ int period;
+ int subtype;
+
+ if (!core_size) {
+ av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
+ return AVERROR(EINVAL);
+ }
+
+ if (!sample_rate) {
+ av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
+ subtype = spdif_dts4_subtype(period);
+
+ if (subtype < 0) {
+ av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
+ "impossible repetition period of %d for the current DTS stream"
+ "(blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
+ blocks << 5, sample_rate);
+ return AVERROR(EINVAL);
+ }
+
+ /* set pkt_offset and DTS IV subtype according to the requested output
+ * rate */
+ ctx->pkt_offset = period * 4;
+ ctx->data_type = IEC958_DTSHD | subtype << 8;
+
+ /* If the bitrate is too high for transmitting at the selected
+ * repetition period setting, strip DTS-HD until a good amount
+ * of consecutive non-overflowing HD frames have been observed.
+ * This generally only happens if the caller is cramming a Master
+ * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
+ if (sizeof(dtshd_start_code) + 2 + pkt_size
+ > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
+ if (!ctx->dtshd_skip)
+ av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
+ "temporarily sending core only\n");
+ if (ctx->dtshd_fallback > 0)
+ ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
+ else
+ /* skip permanently (-1) or just once (0) */
+ ctx->dtshd_skip = 1;
+ }
+ if (ctx->dtshd_skip && core_size) {
+ pkt_size = core_size;
+ if (ctx->dtshd_fallback >= 0)
+ --ctx->dtshd_skip;
+ }
+
+ ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size,
+ sizeof(dtshd_start_code) + 2 + pkt_size);
+ if (!ctx->hd_buf)
+ return AVERROR(ENOMEM);
+
+ memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));
+ AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);
+ memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
+
+ ctx->out_buf = ctx->hd_buf;
+ ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;
+ ctx->length_code = ctx->out_bytes;
+
+ return 0;
+}
+
static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
{
IEC958Context *ctx = s->priv_data;
uint32_t syncword_dts = AV_RB32(pkt->data);
int blocks;
+ int sample_rate = 0;
+ int core_size = 0;
+
+ if (pkt->size < 9)
+ return AVERROR_INVALIDDATA;
switch (syncword_dts) {
case DCA_MARKER_RAW_BE:
blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
+ core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
+ sample_rate = dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
break;
case DCA_MARKER_RAW_LE:
blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
@@ -138,11 +263,22 @@ static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
(((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
ctx->extra_bswap = 1;
break;
+ case DCA_HD_MARKER:
+ /* We only handle HD frames that are paired with core. However,
+ sometimes DTS-HD streams with core have a stray HD frame without
+ core in the beginning of the stream. */
+ av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
+ return AVERROR_INVALIDDATA;
default:
av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
return AVERROR_INVALIDDATA;
}
blocks++;
+
+ if (ctx->dtshd_rate)
+ /* DTS type IV output requested */
+ return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
+
switch (blocks) {
case 512 >> 5: ctx->data_type = IEC958_DTS1; break;
case 1024 >> 5: ctx->data_type = IEC958_DTS2; break;
@@ -152,6 +288,13 @@ static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
blocks << 5);
return AVERROR(ENOSYS);
}
+
+ /* discard extraneous data by default */
+ if (core_size && core_size < pkt->size) {
+ ctx->out_bytes = core_size;
+ ctx->length_code = core_size << 3;
+ }
+
ctx->pkt_offset = blocks << 7;
if (ctx->out_bytes == ctx->pkt_offset) {
@@ -159,6 +302,9 @@ static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)
* preamble as it would not fit in there. This is the case for dts
* discs and dts-in-wav. */
ctx->use_preamble = 0;
+ } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
+ av_log_ask_for_sample(s, "Unrecognized large DTS frame.");
+ /* This will fail with a "bitrate too high" in the caller */
}
return 0;
@@ -394,4 +540,5 @@ AVOutputFormat spdif_muxer = {
spdif_write_header,
spdif_write_packet,
spdif_write_trailer,
+ .priv_class = &class,
};
--
1.7.3
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