[FFmpeg-devel] [PATCH] Lego Mindstorms RSO de/muxer (copied from au.c)

Rafaël Carré rafael.carre
Wed Jul 14 21:54:31 CEST 2010


- format from http://bricxcc.sourceforge.net/
- TODO: IMA ADPCM, it seems to be the CODEC_ID_ADPCM_IMA_WAV codec, but
  predictor/step are not passed in the bitstream.
  I sent a sample to Kostya, if he finds the (fixed for RSO) parameters,
  we could put them in extradata and check if extradata is present in
  the decoder.
- Totally untested on reference implementation (i didn't have/play Lego
 for years), but demuxing/remuxing gives the same output
- Since the header is very simple and has no magic:
      16be  codec id (PCM U8 / ADPCM)
      16be  file size
      16be  sample rate
      16be  play mode (loop)
  I have no idea for a probing function so demuxing has to be forced
  with -f rso

Note: file size is limited to 65535 bytes + 8 bytes header (output is
stored on a ~128kB flash, probably together with code)
---
 Changelog                |    1 +
 libavformat/Makefile     |    2 +
 libavformat/allformats.c |    1 +
 libavformat/rso.c        |  203 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 207 insertions(+), 0 deletions(-)
 create mode 100644 libavformat/rso.c

diff --git a/Changelog b/Changelog
index 6a04869..d408942 100644
--- a/Changelog
+++ b/Changelog
@@ -21,6 +21,7 @@ version <next>:
 - ffplay -exitonkeydown and -exitonmousedown options added
 - native GSM / GSM MS decoder
 - RTP depacketization of QDM2
+- Lego Mindstorms RSO de/muxer
 
 
 
diff --git a/libavformat/Makefile b/libavformat/Makefile
index cab222c..dc5ef8e 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -209,6 +209,8 @@ OBJS-$(CONFIG_RM_DEMUXER)                += rmdec.o rm.o
 OBJS-$(CONFIG_RM_MUXER)                  += rmenc.o rm.o
 OBJS-$(CONFIG_ROQ_DEMUXER)               += idroq.o
 OBJS-$(CONFIG_ROQ_MUXER)                 += raw.o
+OBJS-$(CONFIG_RSO_DEMUXER)               += rso.o raw.o
+OBJS-$(CONFIG_RSO_MUXER)                 += rso.o
 OBJS-$(CONFIG_RPL_DEMUXER)               += rpl.o
 OBJS-$(CONFIG_RTP_MUXER)                 += rtp.o         \
                                             rtpenc_aac.o     \
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 94ab78c..66aab6e 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -174,6 +174,7 @@ void av_register_all(void)
     REGISTER_MUXDEMUX (RM, rm);
     REGISTER_MUXDEMUX (ROQ, roq);
     REGISTER_DEMUXER  (RPL, rpl);
+    REGISTER_MUXDEMUX (RSO, rso);
     REGISTER_MUXER    (RTP, rtp);
     REGISTER_MUXDEMUX (RTSP, rtsp);
     REGISTER_DEMUXER  (SDP, sdp);
diff --git a/libavformat/rso.c b/libavformat/rso.c
new file mode 100644
index 0000000..3af132d
--- /dev/null
+++ b/libavformat/rso.c
@@ -0,0 +1,203 @@
+/*
+ * RSO muxer and demuxer
+ * Copyright (c) 2001 Fabrice Bellard (original AU code)
+ * Copyright ?? 2010 Rafa??l Carr??
+ *
+ * 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 "raw.h"
+#include "riff.h"
+
+#define RSO_HEADER_SIZE 8
+
+/* The ffmpeg codecs we support, and the IDs they have in the file */
+static const AVCodecTag codec_rso_tags[] = {
+    { CODEC_ID_PCM_U8,          0x0100 },
+    { CODEC_ID_ADPCM_IMA_WAV,   0x0101 },
+    { CODEC_ID_NONE, 0 },
+};
+
+#if CONFIG_RSO_MUXER
+static int rso_write_header(AVFormatContext *s)
+{
+    ByteIOContext  *pb  = s->pb;
+    AVCodecContext *enc = s->streams[0]->codec;
+
+    if (!enc->codec_tag)
+        return -1;
+
+    if (enc->channels != 1) {
+        av_log(s, AV_LOG_ERROR, "RSO only supports mono\n");
+        return -1;
+    }
+
+    if (url_is_streamed(s->pb)) {
+        av_log(s, AV_LOG_ERROR, "muxer does not support non seekable output\n");
+        return -1;
+    }
+
+    if (enc->sample_rate >= 1u<<16) {
+        av_log(s, AV_LOG_ERROR, "Sample rate must be < 65536\n");
+        return -1;
+    }
+
+    if (enc->codec_id == CODEC_ID_ADPCM_IMA_WAV) {
+        av_log(s, AV_LOG_ERROR, "ADPCM in RSO not implemented\n");
+        return -1;
+    }
+
+    s->priv_data = NULL;
+
+    /* format header */
+    put_be16(pb, enc->codec_tag);   /* codec ID */
+    put_be16(pb, 0);                /* data size, will be written at EOF */
+    put_be16(pb, enc->sample_rate);
+    put_be16(pb, 0x0000);           /* play mode ? (0x0000 = don't loop) */
+
+    put_flush_packet(pb);
+
+    return 0;
+}
+
+static int rso_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    put_buffer(s->pb, pkt->data, pkt->size);
+    return 0;
+}
+
+static int rso_write_trailer(AVFormatContext *s)
+{
+    ByteIOContext *pb = s->pb;
+    int64_t file_size;
+    int16_t coded_file_size;
+
+    file_size = url_ftell(pb);
+
+    if (file_size < 0)
+        return file_size;
+
+    if (file_size > 0xffff + RSO_HEADER_SIZE) {
+        av_log(s, AV_LOG_WARNING,
+               "Output file is too big (%"PRId64" bytes >= 64kB)\n",
+               file_size);
+        coded_file_size = 0xffff;
+    } else {
+        coded_file_size = file_size - RSO_HEADER_SIZE;
+    }
+
+    /* update file size */
+    url_fseek(pb, 2, SEEK_SET);
+    put_be16(pb, coded_file_size);
+    url_fseek(pb, file_size, SEEK_SET);
+
+    put_flush_packet(pb);
+
+    return 0;
+}
+#endif /* CONFIG_RSO_MUXER */
+
+#if CONFIG_RSO_DEMUXER
+static int rso_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+    ByteIOContext *pb = s->pb;
+    unsigned int id, rate, size, bpp;
+    enum CodecID codec;
+    AVStream *st;
+
+    id =    get_be16(pb);
+    size =  get_be16(pb);
+    rate =  get_be16(pb);
+
+    get_be16(pb);   /* play mode ? (0x0000 = don't loop) */
+
+    codec = ff_codec_get_id(codec_rso_tags, id);
+
+    if (codec == CODEC_ID_ADPCM_IMA_WAV) {
+        av_log(s, AV_LOG_ERROR, "ADPCM in RSO not implemented\n");
+        return -1;
+    }
+
+    bpp = av_get_bits_per_sample(codec);
+    if (!bpp) {
+        av_log_ask_for_sample(s, "could not determine bits per sample\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* now we are ready: build format streams */
+    st = av_new_stream(s, 0);
+    if (!st)
+        return -1;
+    st->duration = size << 3 / bpp;
+    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+    st->codec->codec_tag = id;
+    st->codec->codec_id = codec;
+    st->codec->channels = 1;
+    st->codec->sample_rate = rate;
+    av_set_pts_info(st, 64, 1, rate);
+    return 0;
+}
+
+#define BLOCK_SIZE 1024
+
+static int rso_read_packet(AVFormatContext *s,
+                          AVPacket *pkt)
+{
+    int ret;
+    int bpp = av_get_bits_per_sample(s->streams[0]->codec->codec_id);
+
+    ret= av_get_packet(s->pb, pkt, BLOCK_SIZE * bpp >> 3);
+    if (ret < 0)
+        return ret;
+    pkt->stream_index = 0;
+
+    /* note: we need to modify the packet size here to handle the last
+       packet */
+    pkt->size = ret;
+    return 0;
+}
+#endif /* CONFIG_RSO_DEMUXER */
+
+#if CONFIG_RSO_DEMUXER
+AVInputFormat rso_demuxer = {
+    .name           =   "rso",
+    .long_name      =   NULL_IF_CONFIG_SMALL("Lego Mindstorms RSO format"),
+    .priv_data_size =   0,
+    .read_probe     =   NULL,
+    .read_header    =   rso_read_header,
+    .read_packet    =   rso_read_packet,
+    .read_close     =   NULL,
+    .read_seek      =   pcm_read_seek,
+    .codec_tag      =   (const AVCodecTag* const []){codec_rso_tags, 0},
+};
+#endif
+
+#if CONFIG_RSO_MUXER
+AVOutputFormat rso_muxer = {
+    .name           =   "rso",
+    .long_name      =   NULL_IF_CONFIG_SMALL("Lego Mindstorms RSO format"),
+    .extensions     =   "rso",
+    .priv_data_size =   0,
+    .audio_codec    =   CODEC_ID_PCM_U8,
+    .video_codec    =   CODEC_ID_NONE,
+    .write_header   =   rso_write_header,
+    .write_packet   =   rso_write_packet,
+    .write_trailer  =   rso_write_trailer,
+    .codec_tag      =   (const AVCodecTag* const []){codec_rso_tags, 0},
+};
+#endif
-- 
1.7.0.4





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