split up header parsing function

[ffmpeg] / libavcodec / mimic.c

diff --git a/libavcodec/mimic.c b/libavcodec/mimic.c
index c30ad90274f3ff2d58a21952395167920b5361ad..bbb92299c9f6c8682be0882878223938f6072beb 100644 (file)
--- a/libavcodec/mimic.c
+++ b/libavcodec/mimic.c
@@ -25,6 +25,7 @@
 
 #include "avcodec.h"
 #include "bitstream.h"
+#include "bytestream.h"
 #include "dsputil.h"
 
 #define MIMIC_HEADER_SIZE   20
@@ -109,7 +110,7 @@ static av_cold int mimic_decode_init(AVCodecContext *avctx)
     ctx->prev_index = 0;
     ctx->cur_index = 15;
 
-    if(init_vlc(&ctx->vlc, 8, sizeof(huffbits)/sizeof(huffbits[0]),
+    if(init_vlc(&ctx->vlc, 11, sizeof(huffbits)/sizeof(huffbits[0]),
                  huffbits, 1, 1, huffcodes, 4, 4, 0)) {
         av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
         return -1;
@@ -171,7 +172,7 @@ static int vlc_decode_block(MimicContext *ctx, int num_coeffs, int qscale)
         int value;
         int coeff;
 
-        vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 4);
+        vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 3);
         if(!vlc) /* end-of-block code */
             return 1;
         if(vlc == -1)
@@ -281,24 +282,19 @@ static int mimic_decode_frame(AVCodecContext *avctx, void *data,
     int quality, num_coeffs;
     int swap_buf_size = buf_size - MIMIC_HEADER_SIZE;
 
-    /*
-     * Header structure:
-     *  uint16_t    I_dont_remember;
-     *  uint16_t    quality;
-     *  uint16_t    width;
-     *  uint16_t    height;
-     *  uint32_t    some_constant;
-     *  uint32_t    is_pframe;
-     *  uint32_t    num_coeffs;
-     */
-
     if(buf_size < MIMIC_HEADER_SIZE) {
         av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
         return -1;
     }
 
-    width  = AV_RL16(buf + 4);
-    height = AV_RL16(buf + 6);
+    buf       += 2; /* some constant (always 256) */
+    quality    = bytestream_get_le16(&buf);
+    width      = bytestream_get_le16(&buf);
+    height     = bytestream_get_le16(&buf);
+    buf       += 4; /* some constant */
+    is_pframe  = bytestream_get_le32(&buf);
+    num_coeffs = bytestream_get_byte(&buf);
+    buf       += 3; /* some constant */
 
     if(!ctx->avctx) {
         int i;
@@ -322,10 +318,6 @@ static int mimic_decode_frame(AVCodecContext *avctx, void *data,
         return -1;
     }
 
-    quality    = AV_RL16(buf + 2);
-    is_pframe  = AV_RL32(buf + 12);
-    num_coeffs = buf[16];
-
     if(is_pframe && !ctx->buf_ptrs[ctx->prev_index].data[0]) {
         av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
         return -1;
@@ -346,7 +338,7 @@ static int mimic_decode_frame(AVCodecContext *avctx, void *data,
         return AVERROR_NOMEM;
 
     ctx->dsp.bswap_buf((uint32_t*)ctx->swap_buf,
-                        (const uint32_t*) (buf + MIMIC_HEADER_SIZE),
+                        (const uint32_t*) buf,
                         swap_buf_size>>2);
     init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);
 
@@ -394,4 +386,5 @@ AVCodec mimic_decoder = {
     mimic_decode_end,
     mimic_decode_frame,
     CODEC_CAP_DR1,
+    .long_name = "Mimic",
 };