avcodec: add AHX parser

(cherry picked from commit ddcb47c4c512bf49b22cc6b2d07fade0f96377e3)

libavcodec/Makefile

@@ -1219,6 +1219,7 @@ OBJS-$(CONFIG_AAC_PARSER)              += aac_parser.o aac_ac3_parser.o
 OBJS-$(CONFIG_AC3_PARSER)              += aac_ac3_parser.o ac3tab.o \
                                           ac3_channel_layout_tab.o
 OBJS-$(CONFIG_ADX_PARSER)              += adx_parser.o
+OBJS-$(CONFIG_AHX_PARSER)              += ahx_parser.o
 OBJS-$(CONFIG_AMR_PARSER)              += amr_parser.o
 OBJS-$(CONFIG_APV_PARSER)              += apv_parser.o
 OBJS-$(CONFIG_AV1_PARSER)              += av1_parser.o av1_parse.o

libavcodec/ahx_parser.c

@@ -0,0 +1,78 @@
+/*
+ * 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
+ */
+
+/**
+ * @file
+ * AHX audio parser
+ *
+ * Splits packets into individual blocks.
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "parser.h"
+
+typedef struct AHXParseContext {
+    ParseContext pc;
+    uint32_t header;
+    int size;
+} AHXParseContext;
+
+static int ahx_parse(AVCodecParserContext *s1,
+                     AVCodecContext *avctx,
+                     const uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size)
+{
+    AHXParseContext *s = s1->priv_data;
+    ParseContext *pc = &s->pc;
+    uint32_t state = pc->state;
+    int next = END_NOT_FOUND;
+
+    for (int i = 0; i < buf_size; i++) {
+        state = (state << 8) | buf[i];
+        s->size++;
+        if (s->size == 4 && !s->header)
+            s->header = state;
+        if (s->size > 4 && state == s->header) {
+            next = i - 3;
+            s->size = 0;
+            break;
+        }
+    }
+    pc->state = state;
+
+    if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+        *poutbuf      = NULL;
+        *poutbuf_size = 0;
+        return buf_size;
+    }
+
+    s1->duration = 1152;
+    s1->key_frame = 1;
+
+    *poutbuf = buf;
+    *poutbuf_size = buf_size;
+
+    return next;
+}
+
+const AVCodecParser ff_ahx_parser = {
+    .codec_ids      = { AV_CODEC_ID_AHX },
+    .priv_data_size = sizeof(AHXParseContext),
+    .parser_parse   = ahx_parse,
+    .parser_close   = ff_parse_close,
+};

libavcodec/parsers.c

@@ -24,6 +24,7 @@ extern const AVCodecParser ff_aac_parser;
 extern const AVCodecParser ff_aac_latm_parser;
 extern const AVCodecParser ff_ac3_parser;
 extern const AVCodecParser ff_adx_parser;
+extern const AVCodecParser ff_ahx_parser;
 extern const AVCodecParser ff_amr_parser;
 extern const AVCodecParser ff_apv_parser;
 extern const AVCodecParser ff_av1_parser;