Add CPiA video decoder

The cpia video decoder is intended to be used with the v4l2 demuxer.
There are some small changes to the v4l2 demuxer to support the
variable frame length of the format.
Fixes ticket #1537
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Changelog

@@ -55,6 +55,7 @@ version next:
 - Matroska demuxer now identifies SRT subtitles as AV_CODEC_ID_SUBRIP
   instead of AV_CODEC_ID_TEXT
 - smartblur filter ported from MPlayer
+- CPiA decoder
 
 
 version 0.11:

MAINTAINERS

@@ -134,6 +134,7 @@ Codecs:
   cljr                                  Alex Beregszaszi
   cllc.c                                Derek Buitenhuis
   cook.c, cookdata.h                    Benjamin Larsson
+  cpia.c                                Stephan Hilb
   crystalhd.c                           Philip Langdale
   cscd.c                                Reimar Doeffinger
   dca.c                                 Kostya Shishkov, Benjamin Larsson
@@ -440,4 +441,5 @@ Reynaldo H. Verdejo Pinochet  6E27 CD34 170C C78E 4D4F 5F40 C18E 077F 3114 452A
 Robert Swain                  EE7A 56EA 4A81 A7B5 2001 A521 67FA 362D A2FC 3E71
 Sascha Sommer                 38A0 F88B 868E 9D3A 97D4 D6A0 E823 706F 1E07 0D3C
 Stefano Sabatini              9A43 10F8 D32C D33C 48E7 C52C 5DF2 8E4D B2EE 066B
+Stephan Hilb                  4F38 0B3A 5F39 B99B F505 E562 8D5C 5554 4E17 8863
 Tomas Härdin                  D133 29CA 4EEC 9DB4 7076 F697 B04B 7403 3313 41FD

doc/general.texi

@@ -512,6 +512,7 @@ following image formats are supported:
 @item Cinepak                @tab     @tab  X
 @item Cirrus Logic AccuPak   @tab  X  @tab  X
     @tab fourcc: CLJR
+@item CPiA Video Format      @tab     @tab  X
 @item Creative YUV (CYUV)    @tab     @tab  X
 @item DFA                    @tab     @tab  X
     @tab Codec used in Chronomaster game.

libavcodec/Makefile

@@ -141,6 +141,7 @@ OBJS-$(CONFIG_CLJR_DECODER)            += cljr.o
 OBJS-$(CONFIG_CLJR_ENCODER)            += cljr.o
 OBJS-$(CONFIG_CLLC_DECODER)            += cllc.o
 OBJS-$(CONFIG_COOK_DECODER)            += cook.o
+OBJS-$(CONFIG_CPIA_DECODER)            += cpia.o
 OBJS-$(CONFIG_CSCD_DECODER)            += cscd.o
 OBJS-$(CONFIG_CYUV_DECODER)            += cyuv.o
 OBJS-$(CONFIG_DCA_DECODER)             += dcadec.o dca.o dcadsp.o      \

libavcodec/allcodecs.c

@@ -97,6 +97,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (CINEPAK, cinepak);
     REGISTER_ENCDEC  (CLJR, cljr);
     REGISTER_DECODER (CLLC, cllc);
+    REGISTER_DECODER (CPIA, cpia);
     REGISTER_DECODER (CSCD, cscd);
     REGISTER_DECODER (CYUV, cyuv);
     REGISTER_DECODER (DFA, dfa);

libavcodec/avcodec.h

@@ -280,6 +280,7 @@ enum AVCodecID {
     AV_CODEC_ID_SANM       = MKBETAG('S','A','N','M'),
     AV_CODEC_ID_PAF_VIDEO  = MKBETAG('P','A','F','V'),
     AV_CODEC_ID_AVRN       = MKBETAG('A','V','R','n'),
+    AV_CODEC_ID_CPIA       = MKBETAG('C','P','I','A'),
 
     /* various PCM "codecs" */
     AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs

libavcodec/codec_desc.c

@@ -1183,6 +1183,12 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .name      = "avrn",
         .long_name = NULL_IF_CONFIG_SMALL("Avid AVI Codec"),
     },
+    {
+        .id        = AV_CODEC_ID_CPIA,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "cpia",
+        .long_name = NULL_IF_CONFIG_SMALL("CPiA video format"),
+    },
 
     /* various PCM "codecs" */
     {

libavcodec/cpia.c

+/*
+ * CPiA video decoder.
+ * Copyright (c) 2010 Hans de Goede <hdegoede@redhat.com>
+ *
+ * This decoder is based on the LGPL code available at
+ * https://v4l4j.googlecode.com/svn/v4l4j/trunk/libvideo/libv4lconvert/cpia1.c
+ *
+ * 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 "avcodec.h"
+#include "get_bits.h"
+
+
+#define FRAME_HEADER_SIZE 64
+#define MAGIC_0         0x19    /**< First header byte */
+#define MAGIC_1         0x68    /**< Second header byte */
+#define SUBSAMPLE_420      0
+#define SUBSAMPLE_422      1
+#define YUVORDER_YUYV      0
+#define YUVORDER_UYVY      1
+#define NOT_COMPRESSED     0
+#define COMPRESSED         1
+#define NO_DECIMATION      0
+#define DECIMATION_ENAB    1
+#define EOL             0xfd    /**< End Of Line marker */
+#define EOI             0xff    /**< End Of Image marker */
+
+
+typedef struct {
+    AVFrame frame;
+} CpiaContext;
+
+
+static int cpia_decode_frame(AVCodecContext* avctx,
+        void* data, int* data_size, AVPacket* avpkt)
+{
+    CpiaContext* const cpia = avctx->priv_data;
+    int i,j,ret;
+
+    uint8_t* const header = avpkt->data;
+    uint8_t* src;
+    int src_size;
+    uint16_t linelength;
+    uint8_t skip;
+
+    AVFrame* const frame = &cpia->frame;
+    uint8_t *y, *u, *v, *y_end, *u_end, *v_end;
+
+    // Get buffer filled with previous frame
+    if ((ret = avctx->reget_buffer(avctx, frame)) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed!\n");
+        return ret;
+    }
+
+    // Check header
+    if ( avpkt->size < FRAME_HEADER_SIZE
+      || header[0] != MAGIC_0 || header[1] != MAGIC_1
+      || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422)
+      || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY)
+      || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED)
+      || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB)
+    ) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid header!\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    // currently unsupported properties
+    if (header[17] == SUBSAMPLE_422) {
+        av_log(avctx, AV_LOG_ERROR, "Unsupported subsample!\n");
+        return AVERROR_PATCHWELCOME;
+    }
+    if (header[18] == YUVORDER_UYVY) {
+        av_log(avctx, AV_LOG_ERROR, "Unsupported YUV byte order!\n");
+        return AVERROR_PATCHWELCOME;
+    }
+    if (header[29] == DECIMATION_ENAB) {
+        av_log(avctx, AV_LOG_ERROR, "Decimation unsupported!\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    src = header + FRAME_HEADER_SIZE;
+    src_size = avpkt->size - FRAME_HEADER_SIZE;
+
+    if (header[28] == NOT_COMPRESSED) {
+        frame->pict_type = AV_PICTURE_TYPE_I;
+        frame->key_frame = 1;
+    } else {
+        frame->pict_type = AV_PICTURE_TYPE_P;
+        frame->key_frame = 0;
+    }
+
+
+    for ( i = 0;
+          i < frame->height;
+          i++, src += linelength, src_size -= linelength
+    ) {
+        // Read line length, two byte little endian
+        linelength = AV_RL16(src);
+        src += 2;
+
+        if (src_size < linelength) {
+            frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
+            av_log(avctx, AV_LOG_WARNING, "Frame ended enexpectedly!\n");
+            break;
+        }
+        if (src[linelength - 1] != EOL) {
+            frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
+            av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]);
+            break;
+        }
+
+        /* Update the data pointers. Y data is on every line.
+         * U and V data on every second line
+         */
+        y = &frame->data[0][i * frame->linesize[0]];
+        u = &frame->data[1][(i >> 1) * frame->linesize[1]];
+        v = &frame->data[2][(i >> 1) * frame->linesize[2]];
+        y_end = y + frame->linesize[0] - 1;
+        u_end = u + frame->linesize[1] - 1;
+        v_end = v + frame->linesize[2] - 1;
+
+        if ((i & 1) && header[17] == SUBSAMPLE_420) {
+            /* We are on a odd line and 420 subsample is used.
+             * On this line only Y values are specified, one per pixel.
+             */
+            for (j = 0; j < linelength - 1; j++) {
+                if (y > y_end) {
+                    frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
+                    av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
+                    break;
+                }
+                if ((src[j] & 1) && header[28] == COMPRESSED) {
+                    /* It seems that odd lines are always uncompressed, but
+                     * we do it according to specification anyways.
+                     */
+                    skip = src[j] >> 1;
+                    y += skip;
+                } else {
+                    *(y++) = src[j];
+                }
+            }
+        } else if (header[17] == SUBSAMPLE_420) {
+            /* We are on an even line and 420 subsample is used.
+             * On this line each pair of pixels is described by four bytes.
+             */
+            for (j = 0; j < linelength - 4; ) {
+                if (y + 1 > y_end || u > u_end || v > v_end) {
+                    frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
+                    av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
+                    break;
+                }
+                if ((src[j] & 1) && header[28] == COMPRESSED) {
+                    // Skip amount of pixels and move forward one byte
+                    skip = src[j] >> 1;
+                    y += skip;
+                    u += skip >> 1;
+                    v += skip >> 1;
+                    j++;
+                } else {
+                    // Set image data as specified and move forward 4 bytes
+                    *(y++) = src[j];
+                    *(u++) = src[j+1];
+                    *(y++) = src[j+2];
+                    *(v++) = src[j+3];
+                    j += 4;
+                }
+            }
+        }
+    }
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*) data = *frame;
+
+    return avpkt->size;
+}
+
+static av_cold int cpia_decode_init(AVCodecContext *avctx)
+{
+    // output pixel format
+    avctx->pix_fmt = PIX_FMT_YUV420P;
+
+    /* The default timebase set by the v4l2 demuxer leads to probing which is buggy.
+     * Set some reasonable time_base to skip this.
+     */
+    if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) {
+        avctx->time_base.num = 1;
+        avctx->time_base.den = 60;
+    }
+
+    return 0;
+}
+
+
+AVCodec ff_cpia_decoder = {
+    .name           = "cpia",
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_CPIA,
+    .priv_data_size = sizeof(CpiaContext),
+    .init           = cpia_decode_init,
+    .decode         = cpia_decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
+    .long_name      = NULL_IF_CONFIG_SMALL("CPiA video format"),
+};

libavdevice/v4l2.c

@@ -150,6 +150,7 @@ static struct fmt_map fmt_conversion_table[] = {
     { PIX_FMT_NV12,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_NV12    },
     { PIX_FMT_NONE,    AV_CODEC_ID_MJPEG,    V4L2_PIX_FMT_MJPEG   },
     { PIX_FMT_NONE,    AV_CODEC_ID_MJPEG,    V4L2_PIX_FMT_JPEG    },
+    { PIX_FMT_NONE,    AV_CODEC_ID_CPIA,     V4L2_PIX_FMT_CPIA1   },
 };
 
 static int device_open(AVFormatContext *ctx)
@@ -549,6 +550,13 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
         return AVERROR(errno);
     }
     av_assert0(buf.index < s->buffers);
+
+    /* CPIA is a compressed format and we don't know the exact number of bytes
+     * used by a frame, so set it here as the driver announces it.
+     */
+    if (ctx->video_codec_id == AV_CODEC_ID_CPIA)
+        s->frame_size = buf.bytesused;
+
     if (s->frame_size > 0 && buf.bytesused != s->frame_size) {
         av_log(ctx, AV_LOG_ERROR,
                "The v4l2 frame is %d bytes, but %d bytes are expected\n",
@@ -767,7 +775,7 @@ static int v4l2_read_header(AVFormatContext *s1)
     AVStream *st;
     int res = 0;
     uint32_t desired_format;
-    enum AVCodecID codec_id;
+    enum AVCodecID codec_id = AV_CODEC_ID_NONE;
     enum PixelFormat pix_fmt = PIX_FMT_NONE;
 
     st = avformat_new_stream(s1, NULL);
@@ -828,6 +836,14 @@ static int v4l2_read_header(AVFormatContext *s1)
 
     desired_format = device_try_init(s1, pix_fmt, &s->width, &s->height,
                                      &codec_id);
+
+    /* If no pixel_format was specified, the codec_id was not known up
+     * until now. Set video_codec_id in the context, as codec_id will
+     * not be available outside this function
+     */
+    if (codec_id != AV_CODEC_ID_NONE && s1->video_codec_id == AV_CODEC_ID_NONE)
+        s1->video_codec_id = codec_id;
+
     if (desired_format == 0) {
         av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for "
                "codec_id %d, pix_fmt %d.\n", s1->video_codec_id, pix_fmt);