Similar to ff_spdif_probe() with just an additional checking of
the bit resolution of the container as it may be 16 or 24 for s337m.
---
libavformat/s337m.c | 32 ++++++++++++++++++++++++++++++++
libavformat/s337m.h | 16 ++++++++++++++++
2 files changed, 48 insertions(+)
diff --git a/libavformat/s337m.c b/libavformat/s337m.c
index 2a566e3cba..9d2ac265b6 100644
--- a/libavformat/s337m.c
+++ b/libavformat/s337m.c
@@ -135,6 +135,38 @@ static int s337m_probe(const AVProbeData *p)
return 0;
}
+int ff_s337m_probe(const uint8_t *buf, int size, enum AVCodecID *codec, int
container_word_bits)
+{
+ int pos = 0;
+ int consecutive_codes = 0;
+
+ if ( size < S337M_MIN_OFFSET)
+ return 0;
+ size = FFMIN(3 * S337M_MAX_OFFSET, size);
+ if (container_word_bits != 16 && container_word_bits != 24)
+ return AVERROR_INVALIDDATA;
+
+ do {
+ uint64_t state;
+ int data_type, data_size, offset;
+ while (pos < size - 12 && !buf[pos]) {
+ pos++;
+ }
+ if (pos >= size - 12 || pos < S337M_PROBE_GUARDBAND_MIN_BYTES || pos %
(container_word_bits == 16 ? 4 : 6))
+ return 0;
+ state = container_word_bits == 16 ? AV_RB32(buf + pos) : AV_RB48(buf +
pos);
+ if (!IS_LE_MARKER(state))
+ return 0;
+ data_type = container_word_bits == 16 ? AV_RL16(buf + pos + 4) :
AV_RL24(buf + pos + 6);
+ data_size = container_word_bits == 16 ? AV_RL16(buf + pos + 6) :
AV_RL24(buf + pos + 9);
+ if (s337m_get_offset_and_codec(NULL, state, data_type, data_size,
container_word_bits, &offset, codec))
+ return 0;
+ pos = ++consecutive_codes * (offset + 4*(container_word_bits == 16 ? 4
: 6));
+ } while (consecutive_codes < 3);
+
+ return AVPROBE_SCORE_MAX;
+}
+
static int s337m_read_header(AVFormatContext *s)
{
s->ctx_flags |= AVFMTCTX_NOHEADER;
diff --git a/libavformat/s337m.h b/libavformat/s337m.h
index af2c4c85a3..94e79dce5d 100644
--- a/libavformat/s337m.h
+++ b/libavformat/s337m.h
@@ -21,6 +21,22 @@
#ifndef AVFORMAT_S337M_H
#define AVFORMAT_S337M_H
+#define S337M_MIN_OFFSET 1601*4
+#define S337M_MAX_OFFSET 2002*6
+
+#define S337M_PROBE_GUARDBAND_MIN_BYTES 0
+
+/**
+ * Detect s337m packets in a PCM_S16LE/S24LE stereo stream
+ * Requires 3 samples with enough (S337M_PROBE_GUARDBAND_MIN_BYTES) and clean
(set to zero) guard band
+ * @param p_buf Buffer
+ * @param size Buffer size
+ * @param codec Returns AV_CODEC_ID_DOLBY_E upon successful probing
+ * @param container_word_bits 16 or 24
+ * @return = AVPROBE_SCORE
+ */
+int ff_s337m_probe(const uint8_t *p_buf, int size, enum AVCodecID *codec, int
container_word_bits);
+
/**
* Read s337m packets in a PCM_S16LE/S24LE stereo stream
* Returns the first inner packet found
--
2.30.2
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