Interplay C93 demuxer and video decoder

patch by Anssi Hannula, anssi.hannula gmail com

Originally committed as revision 8643 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 202 insertions, 0 deletions

diff --git a/libavformat/c93.c b/libavformat/c93.c
new file mode 100644
index 0000000000..86f1253985
--- /dev/null
+++ b/libavformat/c93.c
@@ -0,0 +1,202 @@
+/*
+ * Interplay C93 demuxer
+ * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
+ *
+ * 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 "avformat.h"
+#include "voc.h"
+
+typedef struct {
+    uint16_t index;
+    uint8_t length;
+    uint8_t frames;
+} C93BlockRecord;
+
+typedef struct {
+    voc_dec_context_t voc;
+
+    C93BlockRecord block_records[512];
+    int current_block;
+
+    uint32_t frame_offsets[32];
+    int current_frame;
+    int next_pkt_is_audio;
+
+    AVStream *audio;
+} C93DemuxContext;
+
+static int c93_probe(AVProbeData *p)
+{
+    if (p->buf_size < 13)
+        return 0;
+
+    if (p->buf[0] == 0x01 && p->buf[1] == 0x00 &&
+        p->buf[4] == 0x01 + p->buf[2] &&
+        p->buf[8] == p->buf[4] + p->buf[6] &&
+        p->buf[12] == p->buf[8] + p->buf[10])
+        return AVPROBE_SCORE_MAX;
+
+    return 0;
+}
+
+static int c93_read_header(AVFormatContext *s,
+                           AVFormatParameters *ap)
+{
+    AVStream *video;
+    ByteIOContext *pb = &s->pb;
+    C93DemuxContext *c93 = s->priv_data;
+    int i;
+    int framecount = 0;
+
+    for (i = 0; i < 512; i++) {
+        c93->block_records[i].index = get_le16(pb);
+        c93->block_records[i].length = get_byte(pb);
+        c93->block_records[i].frames = get_byte(pb);
+        if (c93->block_records[i].frames > 32) {
+            av_log(s, AV_LOG_ERROR, "too many frames in block\n");
+            return AVERROR_INVALIDDATA;
+        }
+        framecount += c93->block_records[i].frames;
+    }
+
+    /* Audio streams are added if audio packets are found */
+    s->ctx_flags |= AVFMTCTX_NOHEADER;
+
+    video = av_new_stream(s, 0);
+    if (!video)
+        return AVERROR_NOMEM;
+
+    video->codec->codec_type = CODEC_TYPE_VIDEO;
+    video->codec->codec_id = CODEC_ID_C93;
+    video->codec->width = 320;
+    video->codec->height = 192;
+    /* 4:3 320x200 with 8 empty lines */
+    video->codec->sample_aspect_ratio = (AVRational) { 5, 6 };
+    video->time_base = (AVRational) { 2, 25 };
+    video->nb_frames = framecount;
+    video->duration = framecount;
+    video->start_time = 0;
+
+    c93->current_block = 0;
+    c93->current_frame = 0;
+    c93->next_pkt_is_audio = 0;
+    return 0;
+}
+
+#define C93_HAS_PALETTE 0x01
+#define C93_FIRST_FRAME 0x02
+
+static int c93_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    ByteIOContext *pb = &s->pb;
+    C93DemuxContext *c93 = s->priv_data;
+    C93BlockRecord *br = &c93->block_records[c93->current_block];
+    int datasize;
+    int ret, i;
+
+    if (c93->next_pkt_is_audio) {
+        c93->current_frame++;
+        c93->next_pkt_is_audio = 0;
+        datasize = get_le16(pb);
+        if (datasize > 42) {
+            if (!c93->audio) {
+                c93->audio = av_new_stream(s, 1);
+                if (!c93->audio)
+                    return AVERROR_NOMEM;
+                c93->audio->codec->codec_type = CODEC_TYPE_AUDIO;
+            }
+            url_fskip(pb, 26); /* VOC header */
+            ret = voc_get_packet(s, pkt, c93->audio, datasize - 26);
+            if (ret > 0) {
+                pkt->stream_index = 1;
+                pkt->flags |= PKT_FLAG_KEY;
+                return ret;
+            }
+        }
+    }
+    if (c93->current_frame >= br->frames) {
+        if (c93->current_block >= 511 || !br[1].length)
+            return AVERROR_IO;
+        br++;
+        c93->current_block++;
+        c93->current_frame = 0;
+    }
+
+    if (c93->current_frame == 0) {
+        url_fseek(pb, br->index * 2048, SEEK_SET);
+        for (i = 0; i < 32; i++) {
+            c93->frame_offsets[i] = get_le32(pb);
+        }
+    }
+
+    url_fseek(pb,br->index * 2048 +
+            c93->frame_offsets[c93->current_frame], SEEK_SET);
+    datasize = get_le16(pb); /* video frame size */
+
+    ret = av_new_packet(pkt, datasize + 768 + 1);
+    if (ret < 0)
+        return ret;
+    pkt->data[0] = 0;
+    pkt->size = datasize + 1;
+
+    ret = get_buffer(pb, pkt->data + 1, datasize);
+    if (ret < datasize) {
+        ret = AVERROR_IO;
+        goto fail;
+    }
+
+    datasize = get_le16(pb); /* palette size */
+    if (datasize) {
+        if (datasize != 768) {
+            av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+        pkt->data[0] |= C93_HAS_PALETTE;
+        ret = get_buffer(pb, pkt->data + pkt->size, datasize);
+        if (ret < datasize) {
+            ret = AVERROR_IO;
+            goto fail;
+        }
+        pkt->size += 768;
+    }
+    pkt->stream_index = 0;
+    c93->next_pkt_is_audio = 1;
+
+    /* only the first frame is guaranteed to not reference previous frames */
+    if (c93->current_block == 0 && c93->current_frame == 0) {
+        pkt->flags |= PKT_FLAG_KEY;
+        pkt->data[0] |= C93_FIRST_FRAME;
+    }
+    return 0;
+
+    fail:
+    av_free_packet(pkt);
+    return ret;
+}
+
+AVInputFormat c93_demuxer = {
+    "c93",
+    "Interplay C93",
+    sizeof(C93DemuxContext),
+    c93_probe,
+    c93_read_header,
+    c93_read_packet,
+};