[FFmpeg-devel] [PATCH 3/3] avformat: add Gremlin Digital Video demuxer

Paul B Mahol onemda at gmail.com
Fri Jun 2 22:56:19 EEST 2017


Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
 libavformat/Makefile     |   1 +
 libavformat/allformats.c |   1 +
 libavformat/gdv.c        | 161 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 163 insertions(+)
 create mode 100644 libavformat/gdv.c

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 00cba52..80aeed2 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -192,6 +192,7 @@ OBJS-$(CONFIG_G722_MUXER)                += rawenc.o
 OBJS-$(CONFIG_G723_1_DEMUXER)            += g723_1.o
 OBJS-$(CONFIG_G723_1_MUXER)              += rawenc.o
 OBJS-$(CONFIG_G729_DEMUXER)              += g729dec.o
+OBJS-$(CONFIG_GDV_DEMUXER)               += gdv.o
 OBJS-$(CONFIG_GENH_DEMUXER)              += genh.o
 OBJS-$(CONFIG_H261_DEMUXER)              += h261dec.o rawdec.o
 OBJS-$(CONFIG_H261_MUXER)                += rawenc.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index ad516eb..a0e2fb8 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -134,6 +134,7 @@ static void register_all(void)
     REGISTER_MUXDEMUX(G722,             g722);
     REGISTER_MUXDEMUX(G723_1,           g723_1);
     REGISTER_DEMUXER (G729,             g729);
+    REGISTER_DEMUXER (GDV,              gdv);
     REGISTER_DEMUXER (GENH,             genh);
     REGISTER_MUXDEMUX(GIF,              gif);
     REGISTER_MUXDEMUX(GSM,              gsm);
diff --git a/libavformat/gdv.c b/libavformat/gdv.c
new file mode 100644
index 0000000..87bba2f
--- /dev/null
+++ b/libavformat/gdv.c
@@ -0,0 +1,161 @@
+/*
+ * Gremlin Digital Video demuxer
+ * Copyright (c) 2017 Paul B Mahol
+ *
+ * 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 "libavutil/intreadwrite.h"
+
+#include "avformat.h"
+#include "avio.h"
+#include "internal.h"
+
+typedef struct GDVContext {
+    int is_first_video;
+    int is_audio;
+    int audio_size;
+    int audio_stream_index;
+    int video_stream_index;
+    unsigned pal[256];
+} GDVContext;
+
+static int gdv_read_probe(AVProbeData *p)
+{
+    if (AV_RL32(p->buf) == 0x29111994)
+        return AVPROBE_SCORE_MAX;
+
+    return 0;
+}
+
+static int gdv_read_header(AVFormatContext *ctx)
+{
+    GDVContext *gdv = ctx->priv_data;
+    AVIOContext *pb = ctx->pb;
+    AVStream *vst, *ast;
+    unsigned fps, snd_flags, vid_depth;
+
+    avio_skip(pb, 6);
+
+    vst = avformat_new_stream(ctx, 0);
+    if (!vst)
+        return AVERROR(ENOMEM);
+
+    vst->start_time        = 0;
+    vst->duration          =
+    vst->nb_frames         = avio_rl16(pb);
+
+    fps = avio_rl16(pb);
+    snd_flags = avio_rl16(pb);
+    if (snd_flags & 1) {
+        ast = avformat_new_stream(ctx, 0);
+        if (!ast)
+            return AVERROR(ENOMEM);
+
+        ast->start_time = 0;
+        ast->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
+        ast->codecpar->codec_tag   = 0;
+        ast->codecpar->sample_rate = avio_rl16(pb);
+        ast->codecpar->channels    = 1 + !!(snd_flags & 2);
+        if (snd_flags & 8) {
+            ast->codecpar->codec_id = AV_CODEC_ID_GREMLIN_DPCM;
+        } else {
+            ast->codecpar->codec_id = (snd_flags & 4) ? AV_CODEC_ID_PCM_S16LE : AV_CODEC_ID_PCM_U8;
+        }
+
+        avpriv_set_pts_info(ast, 64, 1, ast->codecpar->sample_rate);
+        gdv->audio_size = (ast->codecpar->sample_rate / fps) *
+                           ast->codecpar->channels * (1 + !!(snd_flags & 4)) / (1 + !!(snd_flags & 8));
+        gdv->is_audio = 1;
+    }
+    vid_depth = avio_rl16(pb);
+    avio_skip(pb, 4);
+
+    vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+    vst->codecpar->codec_id   = AV_CODEC_ID_GDV;
+    vst->codecpar->codec_tag  = 0;
+    vst->codecpar->width      = avio_rl16(pb);
+    vst->codecpar->height     = avio_rl16(pb);
+
+    avpriv_set_pts_info(vst, 64, 1, fps);
+
+    if (vid_depth & 1) {
+        int i;
+
+        for (i = 0; i < 256; i++) {
+            unsigned r = avio_r8(pb);
+            unsigned g = avio_r8(pb);
+            unsigned b = avio_r8(pb);
+            gdv->pal[i] = 0xFF << 24 | r << 18 | g << 10 | b << 2;
+        }
+    }
+
+    gdv->is_first_video = 1;
+
+    return 0;
+}
+
+static int gdv_read_packet(AVFormatContext *ctx, AVPacket *pkt)
+{
+    GDVContext *gdv = ctx->priv_data;
+    AVIOContext *pb = ctx->pb;
+    int ret;
+
+    if (avio_feof(pb))
+        return pb->error ? pb->error : AVERROR_EOF;
+
+    if (gdv->audio_size && gdv->is_audio) {
+        ret = av_get_packet(pb, pkt, gdv->audio_size);
+        if (ret < 0)
+            return ret;
+        pkt->stream_index = 1;
+        gdv->is_audio = 0;
+    } else {
+        uint8_t *pal;
+
+        if (avio_rl16(pb) != 0x1305)
+            return AVERROR_INVALIDDATA;
+        ret = av_get_packet(pb, pkt, 4 + avio_rl16(pb));
+        if (ret < 0)
+            return ret;
+        pkt->stream_index = 0;
+        gdv->is_audio = 1;
+
+        if (gdv->is_first_video) {
+            pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
+                                          AVPALETTE_SIZE);
+            if (!pal) {
+                av_packet_unref(pkt);
+                return AVERROR(ENOMEM);
+            }
+            memcpy(pal, gdv->pal, AVPALETTE_SIZE);
+            pkt->flags |= AV_PKT_FLAG_KEY;
+            gdv->is_first_video = 0;
+        }
+    }
+
+    return 0;
+}
+
+AVInputFormat ff_gdv_demuxer = {
+    .name           = "gdv",
+    .long_name      = NULL_IF_CONFIG_SMALL("Gremlin Digital Video"),
+    .priv_data_size = sizeof(GDVContext),
+    .read_probe     = gdv_read_probe,
+    .read_header    = gdv_read_header,
+    .read_packet    = gdv_read_packet,
+};
-- 
2.9.3



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