avcodec: add Screen Recorder Gold Codec decoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>

configure

@@ -2514,6 +2514,7 @@ sonic_decoder_select="golomb rangecoder"
 sonic_encoder_select="golomb rangecoder"
 sonic_ls_encoder_select="golomb rangecoder"
 sp5x_decoder_select="mjpeg_decoder"
+srgc_decoder_select="zlib"
 svq1_decoder_select="hpeldsp"
 svq1_encoder_select="aandcttables hpeldsp me_cmp mpegvideoenc"
 svq3_decoder_select="golomb h264dsp h264parse h264pred hpeldsp tpeldsp videodsp"

doc/general.texi

@@ -857,6 +857,7 @@ following image formats are supported:
     @tab used in some games by Entertainment Software Partners
 @item ScreenPressor          @tab     @tab  X
 @item Screenpresso           @tab     @tab  X
+@item Screen Recorder Gold Codec  @tab     @tab  X
 @item Sierra VMD video       @tab     @tab  X
     @tab Used in Sierra VMD files.
 @item Silicon Graphics Motion Video Compressor 1 (MVC1)  @tab     @tab  X

libavcodec/Makefile

@@ -541,6 +541,7 @@ OBJS-$(CONFIG_SONIC_ENCODER)           += sonic.o
 OBJS-$(CONFIG_SONIC_LS_ENCODER)        += sonic.o
 OBJS-$(CONFIG_SPEEDHQ_DECODER)         += speedhq.o simple_idct.o
 OBJS-$(CONFIG_SP5X_DECODER)            += sp5xdec.o
+OBJS-$(CONFIG_SRGC_DECODER)            += mscc.o
 OBJS-$(CONFIG_SRT_DECODER)             += srtdec.o ass.o htmlsubtitles.o
 OBJS-$(CONFIG_SRT_ENCODER)             += srtenc.o ass_split.o
 OBJS-$(CONFIG_STL_DECODER)             += textdec.o ass.o

libavcodec/allcodecs.c

@@ -317,6 +317,7 @@ static void register_all(void)
     REGISTER_ENCDEC (SNOW,              snow);
     REGISTER_DECODER(SP5X,              sp5x);
     REGISTER_DECODER(SPEEDHQ,           speedhq);
+    REGISTER_DECODER(SRGC,              srgc);
     REGISTER_ENCDEC (SUNRAST,           sunrast);
     REGISTER_ENCDEC (SVQ1,              svq1);
     REGISTER_DECODER(SVQ3,              svq3);

libavcodec/avcodec.h

@@ -444,6 +444,7 @@ enum AVCodecID {
     AV_CODEC_ID_AV1,
     AV_CODEC_ID_BITPACKED,
     AV_CODEC_ID_MSCC,
+    AV_CODEC_ID_SRGC,
 
     /* various PCM "codecs" */
     AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs

libavcodec/codec_desc.c

@@ -1395,6 +1395,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("Mandsoft Screen Capture Codec"),
         .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
     },
+    {
+        .id        = AV_CODEC_ID_SRGC,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "srgc",
+        .long_name = NULL_IF_CONFIG_SMALL("Screen Recorder Gold Codec"),
+        .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
+    },
 
     /* image codecs */
     {

libavcodec/mscc.c

@@ -121,6 +121,8 @@ static int decode_frame(AVCodecContext *avctx,
 {
     MSCCContext *s = avctx->priv_data;
     AVFrame *frame = data;
+    uint8_t *buf = avpkt->data;
+    int buf_size = avpkt->size;
     GetByteContext gb;
     PutByteContext pb;
     int ret, j;
@@ -130,15 +132,19 @@ static int decode_frame(AVCodecContext *avctx,
     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
         return ret;
 
-    avpkt->data[2] ^= avpkt->data[0];
+    if (avctx->codec_id == AV_CODEC_ID_MSCC) {
+        avpkt->data[2] ^= avpkt->data[0];
+        buf += 2;
+        buf_size -= 2;
+    }
 
     ret = inflateReset(&s->zstream);
     if (ret != Z_OK) {
         av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
         return AVERROR_UNKNOWN;
     }
-    s->zstream.next_in   = avpkt->data + 2;
-    s->zstream.avail_in  = avpkt->size - 2;
+    s->zstream.next_in   = buf;
+    s->zstream.avail_in  = buf_size;
     s->zstream.next_out  = s->decomp_buf;
     s->zstream.avail_out = s->decomp_size;
     ret = inflate(&s->zstream, Z_FINISH);
@@ -229,3 +235,15 @@ AVCodec ff_mscc_decoder = {
     .decode           = decode_frame,
     .capabilities     = AV_CODEC_CAP_DR1,
 };
+
+AVCodec ff_srgc_decoder = {
+    .name             = "srgc",
+    .long_name        = NULL_IF_CONFIG_SMALL("Screen Recorder Gold Codec"),
+    .type             = AVMEDIA_TYPE_VIDEO,
+    .id               = AV_CODEC_ID_SRGC,
+    .priv_data_size   = sizeof(MSCCContext),
+    .init             = decode_init,
+    .close            = decode_close,
+    .decode           = decode_frame,
+    .capabilities     = AV_CODEC_CAP_DR1,
+};

libavcodec/version.h

@@ -28,7 +28,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR  57
-#define LIBAVCODEC_VERSION_MINOR  92
+#define LIBAVCODEC_VERSION_MINOR  93
 #define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \

libavformat/riff.c

@@ -453,6 +453,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_CLEARVIDEO,   MKTAG('U', 'C', 'O', 'D') },
     { AV_CODEC_ID_AV1,          MKTAG('A', 'V', '0', '1') },
     { AV_CODEC_ID_MSCC,         MKTAG('M', 'S', 'C', 'C') },
+    { AV_CODEC_ID_SRGC,         MKTAG('S', 'R', 'G', 'C') },
     { AV_CODEC_ID_NONE,         0 }
 };