[FFmpeg-devel] [PATCH v3 3/6] avformat/s337m: Make available as subdemuxer
Nicolas Gaullier
nicolas.gaullier at arkena.com
Tue Aug 6 18:08:12 EEST 2019
---
libavformat/s337m.c | 64 ++++++++++++++++++++++++++++++++++++++++++++---------
libavformat/s337m.h | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 117 insertions(+), 11 deletions(-)
create mode 100644 libavformat/s337m.h
diff --git a/libavformat/s337m.c b/libavformat/s337m.c
index 22140297e6..3ec78d36e4 100644
--- a/libavformat/s337m.c
+++ b/libavformat/s337m.c
@@ -21,17 +21,7 @@
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "spdif.h"
-
-#define MARKER_16LE 0x72F81F4E
-#define MARKER_20LE 0x20876FF0E154
-#define MARKER_24LE 0x72F8961F4EA5
-
-#define IS_16LE_MARKER(state) ((state & 0xFFFFFFFF) == MARKER_16LE)
-#define IS_20LE_MARKER(state) ((state & 0xF0FFFFF0FFFF) == MARKER_20LE)
-#define IS_24LE_MARKER(state) ((state & 0xFFFFFFFFFFFF) == MARKER_24LE)
-#define IS_LE_MARKER(state) (IS_16LE_MARKER(state) || IS_20LE_MARKER(state) || IS_24LE_MARKER(state))
-
-int avpriv_s337m_get_packet(void *avc, AVIOContext *pb, AVPacket *pkt, int size, enum AVCodecID *codec);
+#include "s337m.h"
static int s337m_get_offset_and_codec(void *avc,
uint64_t state,
@@ -129,6 +119,58 @@ static int s337m_probe(const AVProbeData *p)
return 0;
}
+int avpriv_s337m_probe_stream(void *avc, AVIOContext *pb, AVStream **st, int size)
+{
+ if ( size >= S337M_MIN_OFFSET &&
+ ((*st)->codecpar->codec_id == AV_CODEC_ID_PCM_S16LE || (*st)->codecpar->codec_id == AV_CODEC_ID_PCM_S24LE) &&
+ (*st)->codecpar->channels == 2) {
+ uint8_t *buf;
+ int64_t data_offset;
+ int pos = 0;
+
+ size = FFMIN(size, S337M_MAX_OFFSET);
+ if (!(buf = av_mallocz(size))) {
+ return AVERROR(ENOMEM);
+ }
+ data_offset = avio_tell(pb);
+ if (avio_read(pb, buf, size) != size) {
+ av_freep(&buf);
+ return AVERROR(EIO);
+ }
+ avio_seek(pb, data_offset, SEEK_SET);
+
+ while (pos < size - 9 && !buf[pos]) {
+ pos++;
+ }
+ if (pos < size - 9 && pos >= S337M_PROBE_GUARDBAND_MIN_BYTES) {
+ uint64_t state;
+ int data_type = -1, data_size, offset;
+
+ if ((*st)->codecpar->bits_per_coded_sample == 16) {
+ state = AV_RB32(buf + pos);
+ if (IS_16LE_MARKER(state)) {
+ data_type = AV_RL16(buf + pos + 4);
+ data_size = AV_RL16(buf + pos + 6);
+ }
+ } else if ((*st)->codecpar->bits_per_coded_sample == 24) {
+ state = AV_RB48(buf + pos);
+ if (IS_20LE_MARKER(state) || IS_24LE_MARKER(state)) {
+ data_type = AV_RL24(buf + pos + 6);
+ data_size = AV_RL24(buf + pos + 9);
+ }
+ }
+ if (data_type >= 0 && !s337m_get_offset_and_codec(avc, state, data_type, data_size, &offset, &(*st)->codecpar->codec_id)) {
+ double s337m_phase = pos * 4 / (*st)->codecpar->bits_per_coded_sample / (*st)->codecpar->sample_rate;
+ av_log(avc, AV_LOG_INFO, "s337m detected with phase = %.6fs\n", s337m_phase);
+ if ((*st)->codecpar->codec_id == AV_CODEC_ID_DOLBY_E && (s337m_phase < DOLBY_E_PHASE_MIN || s337m_phase > DOLBY_E_PHASE_MAX))
+ av_log(avc, AV_LOG_WARNING, "Dolby E phase is out of valid range (%.6fs-%.6fs)\n", DOLBY_E_PHASE_MIN, DOLBY_E_PHASE_MAX);
+ }
+ }
+ av_freep(&buf);
+ }
+ return 0;
+}
+
static int s337m_read_header(AVFormatContext *s)
{
s->ctx_flags |= AVFMTCTX_NOHEADER;
diff --git a/libavformat/s337m.h b/libavformat/s337m.h
new file mode 100644
index 0000000000..0f21a23a30
--- /dev/null
+++ b/libavformat/s337m.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2017 foo86
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFORMAT_S337M_H
+#define AVFORMAT_S337M_H
+
+#define MARKER_16LE 0x72F81F4E
+#define MARKER_20LE 0x20876FF0E154
+#define MARKER_24LE 0x72F8961F4EA5
+
+#define IS_16LE_MARKER(state) ((state & 0xFFFFFFFF) == MARKER_16LE)
+#define IS_20LE_MARKER(state) ((state & 0xF0FFFFF0FFFF) == MARKER_20LE)
+#define IS_24LE_MARKER(state) ((state & 0xFFFFFFFFFFFF) == MARKER_24LE)
+#define IS_LE_MARKER(state) (IS_16LE_MARKER(state) || IS_20LE_MARKER(state) || IS_24LE_MARKER(state))
+
+#define S337M_MIN_OFFSET 1601*4
+#define S337M_MAX_OFFSET 2002*6
+
+#define S337M_PROBE_GUARDBAND_MIN_BYTES 0
+#define DOLBY_E_PHASE_MIN 0.000610
+#define DOLBY_E_PHASE_MAX 0.001050
+
+/**
+ * Detect s337m packets in a PCM_S16LE/S24LE stereo stream
+ * If found, the codec of the stream is updated
+ * Requires a single sample with enough (S337M_PROBE_GUARDBAND_MIN_BYTES) and clean (set to zero) guard band
+ * @param avc For av_log
+ * @param pb Associated IO context
+ * @param st Streams
+ * @param size Maximum IO read size available for probing at current position
+ * @return = 0 if no error encountered (even if no s337m was found)
+ */
+int avpriv_s337m_probe_stream(void *avc, AVIOContext *pb, AVStream **st, int size);
+
+/**
+ * Read s337m packets in a PCM_S16LE/S24LE stereo stream
+ * Returns the first inner packet found
+ * @param avc For av_log
+ * @param pb Associated IO context
+ * @param pkt On success, returns a DOLBY E packet
+ * @param size Maximum IO read size available for reading at current position
+ * @param codec Returns AV_CODEC_ID_DOLBY_E
+ * @return = 0 on success (an error is raised if no s337m was found)
+ */
+int avpriv_s337m_get_packet(void *avc, AVIOContext *pb, AVPacket *pkt, int size, enum AVCodecID *codec);
+
+#endif /* AVFORMAT_S337M_H */
--
2.14.1.windows.1
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