avcodec: add a ffv1 parser

Only setting frame and stream properties. No packetization is performed.

Signed-off-by: James Almer <jamrial@gmail.com>

1 files changed, 86 insertions, 0 deletions

diff --git a/libavcodec/ffv1_parser.c b/libavcodec/ffv1_parser.c
new file mode 100644
index 0000000000..f36a5dfdbd
--- /dev/null
+++ b/libavcodec/ffv1_parser.c
@@ -0,0 +1,86 @@
+/*
+ * 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
+ */
+
+#include "avcodec.h"
+#include "ffv1.h"
+#include "rangecoder.h"
+
+typedef struct FFV1ParseContext {
+    FFV1Context f;
+    int got_first;
+} FFV1ParseContext;
+
+static int parse(AVCodecParserContext *s,
+                 AVCodecContext *avctx,
+                 const uint8_t **poutbuf, int *poutbuf_size,
+                 const uint8_t *buf, int buf_size)
+{
+    FFV1ParseContext *p = s->priv_data;
+    FFV1Context *f = &p->f;
+    RangeCoder c;
+    uint8_t keystate = 128;
+
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+
+    if (!p->got_first) {
+        int ret = ff_ffv1_common_init(avctx, f);
+        p->got_first = 1;
+        if (ret < 0)
+            return buf_size;
+
+        if (avctx->extradata_size > 0 && (ret = ff_ffv1_read_extra_header(f)) < 0)
+            return buf_size;
+    }
+
+    ff_init_range_decoder(&c, buf, buf_size);
+    ff_build_rac_states(&c, 0.05 * (1LL << 32), 256 - 8);
+
+    f->avctx = avctx;
+    s->key_frame = get_rac(&c, &keystate);
+    s->pict_type = AV_PICTURE_TYPE_I;
+    s->field_order = AV_FIELD_UNKNOWN;
+    s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
+
+    if (s->key_frame) {
+        uint8_t state[CONTEXT_SIZE];
+        memset(state, 128, sizeof(state));
+        ff_ffv1_parse_header(f, &c, state);
+    }
+
+    s->width  = f->width;
+    s->height = f->height;
+    s->format = f->pix_fmt;
+
+    return buf_size;
+}
+
+static void close(AVCodecParserContext *s)
+{
+    FFV1ParseContext *p = s->priv_data;
+
+    p->f.avctx = NULL;
+    ff_ffv1_close(&p->f);
+}
+
+const AVCodecParser ff_ffv1_parser = {
+    .codec_ids    = { AV_CODEC_ID_FFV1 },
+    .priv_data_size = sizeof(FFV1ParseContext),
+    .parser_parse = parse,
+    .parser_close = close,
+};