@@ -24,9 +24,16 @@

 #include "libavcodec/bytestream.h"

 #include "avformat.h"

+typedef struct A64MuxerContext {

+    int interleaved;

+    AVPacket prev_pkt;

+    int prev_frame_count;

+} A64MuxerContext;

+

 static int a64_write_header(struct AVFormatContext *s)

 {

     AVCodecContext *avctx=s->streams[0]->codec;

+    A64MuxerContext *c = s->priv_data;

     uint8_t header[5] = {

         0x00, //load

         0x40, //address

@@ -34,6 +41,7 @@ static int a64_write_header(struct AVFormatContext *s)

         0x00, //charset_lifetime (multi only)

         0x00  //fps in 50/fps;

     };

+    c->interleaved = 0;

     switch (avctx->codec->id) {

     case CODEC_ID_A64_MULTI:

         header[2] = 0x00;

@@ -50,16 +58,99 @@ static int a64_write_header(struct AVFormatContext *s)

         break;

     }

     put_buffer(s->pb, header, 2);

+    c->prev_pkt.size = 0;

+    c->prev_frame_count = 0;

     return 0;

 }

 static int a64_write_packet(struct AVFormatContext *s, AVPacket *pkt)

 {

-    put_buffer(s->pb, pkt->data, pkt->size);

+    AVCodecContext *avctx = s->streams[0]->codec;

+    A64MuxerContext *c = s->priv_data;

+    int i, j;

+    int ch_chunksize;

+    int lifetime;

+    int frame_count;

+    int charset_size;

+    int frame_size;

+    int num_frames;

+

+    /* fetch values from extradata */

+    switch (avctx->codec->id) {

+    case CODEC_ID_A64_MULTI:

+    case CODEC_ID_A64_MULTI5:

+        if(c->interleaved) {

+            /* Write interleaved, means we insert chunks of the future charset before each current frame.

+             * Reason: if we load 1 charset + corresponding frames in one block on c64, we need to store

+             * them first and then display frame by frame to keep in sync. Thus we would read and write

+             * the data for colram from/to ram first and waste too much time. If we interleave and send the

+             * charset beforehand, we assemble a new charset chunk by chunk, write current screen data to

+             * screen-ram to be displayed and decode the colram directly to colram-location $d800 during

+             * the overscan, while reading directly from source

+             * This is the only way so far, to achieve 25fps on c64 */

+            if(avctx->extradata) {

+                /* fetch values from extradata */

+                lifetime     = AV_RB32(avctx->extradata + 0);

+                frame_count  = AV_RB32(avctx->extradata + 4);

+                charset_size = AV_RB32(avctx->extradata + 8);

+                frame_size   = AV_RB32(avctx->extradata + 12);

+

+                /* TODO: sanity checks? */

+            }

+            else {

+                av_log(avctx, AV_LOG_ERROR, "extradata not set\n");

+                return AVERROR(EINVAL);

+            }

+            ch_chunksize=charset_size/lifetime;

+            /* TODO: check if charset/size is % lifetime, but maybe check in codec */

+            if(pkt->data) num_frames = lifetime;

+            else num_frames = c->prev_frame_count;

+            for(i = 0; i < num_frames; i++) {

+                if(pkt->data) {

+                    /* if available, put newest charset chunk into buffer */

+                    put_buffer(s->pb, pkt->data + ch_chunksize * i, ch_chunksize);

+                }

+                else {

+                       /* a bit ugly, but is there an alternative to put many zeros? */

+                        for(j = 0; j < ch_chunksize; j++) put_byte(s->pb, 0);

+                }

+                if(c->prev_pkt.data) {

+                    /* put frame (screen + colram) from last packet into buffer */

+                    put_buffer(s->pb, c->prev_pkt.data + charset_size + frame_size * i, frame_size);

+                }

+                else {

+                       /* a bit ugly, but is there an alternative to put many zeros? */

+                        for(j = 0; j < frame_size; j++) put_byte(s->pb, 0);

+                }

+            }

+            /* backup current packet for next turn */

+            if(pkt->data) {

+                av_new_packet(&c->prev_pkt, pkt->size);

+                memcpy(c->prev_pkt.data, pkt->data, pkt->size);

+            }

+            c->prev_frame_count = frame_count;

+            break;

+        }

+        default:

+            /* Write things as is. Nice for self-contained frames from non-multicolor modes or if played

+             * directly from ram and not from a streaming device (rrnet/mmc) */

+            if(pkt) put_buffer(s->pb, pkt->data, pkt->size);

+        break;

+    }

+

     put_flush_packet(s->pb);

     return 0;

 }

+static int a64_write_trailer(struct AVFormatContext *s)

+{

+    A64MuxerContext *c = s->priv_data;

+    AVPacket pkt;

+    /* need to flush last packet? */

+    if(c->interleaved) a64_write_packet(s, &pkt);

+    return 0;

+}

+

 AVOutputFormat a64_muxer = {

     .name = "a64",

     .long_name = NULL_IF_CONFIG_SMALL("a64 - video for Commodore 64"),

@@ -69,4 +160,5 @@ AVOutputFormat a64_muxer = {

     .video_codec = CODEC_ID_A64_MULTI,

     a64_write_header,

     a64_write_packet,

+    a64_write_trailer

 };