Implement YOP demuxer and video decoder.

Patch by Mohamed Naufal gmailify(naufal11).

Originally committed as revision 22724 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 216 insertions, 0 deletions

diff --git a/libavformat/yop.c b/libavformat/yop.c
new file mode 100644
index 0000000000..36c9369916
--- /dev/null
+++ b/libavformat/yop.c
@@ -0,0 +1,216 @@
+/**
+ * @file libavformat/yop.c
+ * Psygnosis YOP demuxer
+ *
+ * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
+ * derived from the code by
+ * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@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 "libavutil/intreadwrite.h"
+#include "avformat.h"
+
+typedef struct yop_dec_context {
+    AVPacket video_packet;
+
+    int odd_frame;
+    int frame_size;
+    int audio_block_length;
+    int palette_size;
+} YopDecContext;
+
+static int yop_probe(AVProbeData *probe_packet)
+{
+    if (AV_RB16(probe_packet->buf) == AV_RB16("YO")  &&
+        probe_packet->buf[6]                         &&
+        probe_packet->buf[7]                         &&
+        !(probe_packet->buf[8] & 1)                  &&
+        !(probe_packet->buf[10] & 1))
+        return AVPROBE_SCORE_MAX * 3 / 4;
+
+    return 0;
+}
+
+static int yop_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+    YopDecContext *yop = s->priv_data;
+    ByteIOContext *pb  = s->pb;
+
+    AVCodecContext *audio_dec, *video_dec;
+    AVStream *audio_stream, *video_stream;
+
+    int frame_rate, ret;
+
+    audio_stream = av_new_stream(s, 0);
+    video_stream = av_new_stream(s, 1);
+
+    // Extra data that will be passed to the decoder
+    video_stream->codec->extradata_size = 8;
+
+    video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
+                                                FF_INPUT_BUFFER_PADDING_SIZE);
+
+    if (!video_stream->codec->extradata)
+        return AVERROR(ENOMEM);
+
+    // Audio
+    audio_dec               = audio_stream->codec;
+    audio_dec->codec_type   = CODEC_TYPE_AUDIO;
+    audio_dec->codec_id     = CODEC_ID_ADPCM_IMA_WS;
+    audio_dec->channels     = 1;
+    audio_dec->sample_rate  = 22050;
+
+    // Video
+    video_dec               = video_stream->codec;
+    video_dec->codec_type   = CODEC_TYPE_VIDEO;
+    video_dec->codec_id     = CODEC_ID_YOP;
+
+    url_fskip(pb, 6);
+
+    frame_rate              = get_byte(pb);
+    yop->frame_size         = get_byte(pb) * 2048;
+    video_dec->width        = get_le16(pb);
+    video_dec->height       = get_le16(pb);
+
+    video_stream->sample_aspect_ratio = (AVRational){1, 2};
+
+    ret = get_buffer(pb, video_dec->extradata, 8);
+    if (ret < 8)
+        return ret < 0 ? ret : AVERROR_EOF;
+
+    yop->palette_size       = video_dec->extradata[0] * 3 + 4;
+    yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
+
+    // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
+    if (yop->audio_block_length < 920 ||
+        yop->audio_block_length + yop->palette_size >= yop->frame_size) {
+        av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    url_fseek(pb, 2048, SEEK_SET);
+
+    av_set_pts_info(video_stream, 32, 1, frame_rate);
+
+    return 0;
+}
+
+static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    YopDecContext *yop = s->priv_data;
+    ByteIOContext *pb  = s->pb;
+
+    int ret;
+    int actual_video_data_size = yop->frame_size -
+                                 yop->audio_block_length - yop->palette_size;
+
+    yop->video_packet.stream_index = 1;
+
+    if (yop->video_packet.data) {
+        *pkt                   =  yop->video_packet;
+        yop->video_packet.data =  NULL;
+        yop->video_packet.size =  0;
+        pkt->data[0]           =  yop->odd_frame;
+        pkt->flags             |= PKT_FLAG_KEY;
+        yop->odd_frame         ^= 1;
+        return pkt->size;
+    }
+    ret = av_new_packet(&yop->video_packet,
+                        yop->frame_size - yop->audio_block_length);
+    if (ret < 0)
+        return ret;
+
+    yop->video_packet.pos = url_ftell(pb);
+
+    ret = get_buffer(pb, yop->video_packet.data, yop->palette_size);
+    if (ret < 0) {
+        goto err_out;
+    }else if (ret < yop->palette_size) {
+        ret = AVERROR_EOF;
+        goto err_out;
+    }
+
+    ret = av_get_packet(pb, pkt, 920);
+    if (ret < 0)
+        goto err_out;
+
+    // Set position to the start of the frame
+    pkt->pos = yop->video_packet.pos;
+
+    url_fskip(pb, yop->audio_block_length - ret);
+
+    ret = get_buffer(pb, yop->video_packet.data + yop->palette_size,
+                     actual_video_data_size);
+    if (ret < 0)
+        goto err_out;
+    else if (ret < actual_video_data_size)
+        av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
+
+    // Arbitrarily return the audio data first
+    return yop->audio_block_length;
+
+err_out:
+    av_free_packet(&yop->video_packet);
+    return ret;
+}
+
+static int yop_read_close(AVFormatContext *s)
+{
+    YopDecContext *yop = s->priv_data;
+    av_free_packet(&yop->video_packet);
+    return 0;
+}
+
+static int yop_read_seek(AVFormatContext *s, int stream_index,
+                         int64_t timestamp, int flags)
+{
+    YopDecContext *yop = s->priv_data;
+    int64_t frame_pos, pos_min, pos_max;
+    int frame_count;
+
+    av_free_packet(&yop->video_packet);
+
+    if (!stream_index)
+        return -1;
+
+    pos_min        = s->data_offset;
+    pos_max        = url_fsize(s->pb) - yop->frame_size;
+    frame_count    = (pos_max - pos_min) / yop->frame_size;
+
+    timestamp      = FFMAX(0, FFMIN(frame_count, timestamp));
+
+    frame_pos      = timestamp * yop->frame_size + pos_min;
+    yop->odd_frame = timestamp & 1;
+
+    url_fseek(s->pb, frame_pos, SEEK_SET);
+    return 0;
+}
+
+AVInputFormat yop_demuxer = {
+    "yop",
+    NULL_IF_CONFIG_SMALL("Psygnosis YOP Format"),
+    sizeof(YopDecContext),
+    yop_probe,
+    yop_read_header,
+    yop_read_packet,
+    yop_read_close,
+    yop_read_seek,
+    .extensions = "yop",
+    .flags = AVFMT_GENERIC_INDEX,
+};