HAM6/HAM8 support for IFF demuxer/decoder

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/iff.c

@@ -29,6 +29,7 @@
  * http://wiki.multimedia.cx/index.php?title=IFF
  */
 
+#include "libavcodec/bytestream.h"
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"
 
@@ -40,6 +41,7 @@
 #define ID_PBM        MKTAG('P','B','M',' ')
 #define ID_ILBM       MKTAG('I','L','B','M')
 #define ID_BMHD       MKTAG('B','M','H','D')
+#define ID_CAMG       MKTAG('C','A','M','G')
 #define ID_CMAP       MKTAG('C','M','A','P')
 
 #define ID_FORM       MKTAG('F','O','R','M')
@@ -60,6 +62,16 @@
 
 #define PACKET_SIZE 1024
 
+/**
+ * This number of bytes if added at the beginning of each AVPacket
+ * which contain additional information about video properties
+ * which has to be shared between demuxer and decoder.
+ * This number may change between frames, e.g. the demuxer might
+ * set it to smallest possible size of 2 to indicate that there's
+ * no extradata changing in this frame.
+ */
+#define IFF_EXTRA_VIDEO_SIZE 9
+
 typedef enum {
     COMP_NONE,
     COMP_FIB,
@@ -76,6 +88,12 @@ typedef struct {
     uint32_t  body_size;
     uint32_t  sent_bytes;
     uint32_t  audio_frame_count;
+    unsigned  compression;  ///< delta compression method used
+    unsigned  bpp;          ///< bits per plane to decode (differs from bits_per_coded_sample if HAM)
+    unsigned  ham;          ///< 0 if non-HAM or number of hold bits (6 for bpp > 6, 4 otherwise)
+    unsigned  flags;        ///< 1 for EHB, 0 is no extra half darkening
+    unsigned  transparency; ///< transparency color index in palette
+    unsigned  masking;      ///< masking method used
 } IffDemuxContext;
 
 
@@ -126,8 +144,12 @@ static int iff_read_header(AVFormatContext *s,
     IffDemuxContext *iff = s->priv_data;
     AVIOContext *pb = s->pb;
     AVStream *st;
+    uint8_t *buf;
     uint32_t chunk_id, data_size;
     int compression = -1;
+    uint32_t screenmode = 0;
+    unsigned transparency = 0;
+    unsigned masking = 0; // no mask
 
     st = av_new_stream(s, 0);
     if (!st)
@@ -171,12 +193,18 @@ static int iff_read_header(AVFormatContext *s,
             st->codec->channels = (avio_rb32(pb) < 6) ? 1 : 2;
             break;
 
+        case ID_CAMG:
+            if (data_size < 4)
+                return AVERROR_INVALIDDATA;
+            screenmode                = avio_rb32(pb);
+            break;
+
         case ID_CMAP:
-            st->codec->extradata_size = data_size;
-            st->codec->extradata      = av_malloc(data_size);
+            st->codec->extradata_size = data_size + IFF_EXTRA_VIDEO_SIZE;
+            st->codec->extradata      = av_malloc(data_size + IFF_EXTRA_VIDEO_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
             if (!st->codec->extradata)
                 return AVERROR(ENOMEM);
-            if (avio_read(pb, st->codec->extradata, data_size) < 0)
+            if (avio_read(pb, st->codec->extradata + IFF_EXTRA_VIDEO_SIZE, data_size) < 0)
                 return AVERROR(EIO);
             break;
 
@@ -188,12 +216,15 @@ static int iff_read_header(AVFormatContext *s,
             st->codec->height                = avio_rb16(pb);
             avio_skip(pb, 4); // x, y offset
             st->codec->bits_per_coded_sample = avio_r8(pb);
-            if (data_size >= 11) {
-                avio_skip(pb, 1); // masking
+            if (data_size >= 10)
+                masking                      = avio_r8(pb);
+            if (data_size >= 11)
                 compression                  = avio_r8(pb);
+            if (data_size >= 14) {
+                avio_skip(pb, 1); // padding
+                transparency                 = avio_rb16(pb);
             }
             if (data_size >= 16) {
-                avio_skip(pb, 3); // paddding, transparent
                 st->sample_aspect_ratio.num  = avio_r8(pb);
                 st->sample_aspect_ratio.den  = avio_r8(pb);
             }
@@ -253,6 +284,31 @@ static int iff_read_header(AVFormatContext *s,
         break;
 
     case AVMEDIA_TYPE_VIDEO:
+        iff->compression  = compression;
+        iff->bpp          = st->codec->bits_per_coded_sample;
+        if ((screenmode & 0x800 /* Hold And Modify */) && iff->bpp <= 8) {
+            iff->ham      = iff->bpp > 6 ? 6 : 4;
+            st->codec->bits_per_coded_sample = 24;
+        }
+        iff->flags        = (screenmode & 0x80 /* Extra HalfBrite */) && iff->bpp <= 8;
+        iff->masking      = masking;
+        iff->transparency = transparency;
+
+        if (!st->codec->extradata) {
+            st->codec->extradata_size = IFF_EXTRA_VIDEO_SIZE;
+            st->codec->extradata      = av_malloc(IFF_EXTRA_VIDEO_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
+            if (!st->codec->extradata)
+                return AVERROR(ENOMEM);
+        }
+        buf = st->codec->extradata;
+        bytestream_put_be16(&buf, IFF_EXTRA_VIDEO_SIZE);
+        bytestream_put_byte(&buf, iff->compression);
+        bytestream_put_byte(&buf, iff->bpp);
+        bytestream_put_byte(&buf, iff->ham);
+        bytestream_put_byte(&buf, iff->flags);
+        bytestream_put_be16(&buf, iff->transparency);
+        bytestream_put_byte(&buf, iff->masking);
+
         switch (compression) {
         case BITMAP_RAW:
             st->codec->codec_id = CODEC_ID_IFF_ILBM;
@@ -293,7 +349,15 @@ static int iff_read_packet(AVFormatContext *s,
         }
         interleave_stereo(sample_buffer, pkt->data, PACKET_SIZE);
     } else if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
-        ret = av_get_packet(pb, pkt, iff->body_size);
+        uint8_t *buf;
+
+        if (av_new_packet(pkt, iff->body_size + 2) < 0) {
+            return AVERROR(ENOMEM);
+        }
+
+        buf = pkt->data;
+        bytestream_put_be16(&buf, 2);
+        ret = avio_read(pb, buf, iff->body_size);
     } else {
         ret = av_get_packet(pb, pkt, PACKET_SIZE);
     }