libavcodec: v4l2: add support for v4l2 mem2mem codecs

    This patchset enhances Alexis Ballier's original patch and validates
    it using Qualcomm's Venus hardware (driver recently landed upstream
    [1]).

    This has been tested on Qualcomm's DragonBoard 410c and 820c
    Configure/make scripts have been validated on Ubuntu 10.04 and
    16.04.

    Tested decoders:
           - h264
           - h263
           - mpeg4
           - vp8
           - vp9
           - hevc

    Tested encoders:
           - h264
           - h263
           - mpeg4

    Tested transcoding (concurrent encoding/decoding)

    Some of the changes introduced:
        - v4l2: code cleanup and abstractions added
        - v4l2: follow the new encode/decode api.
        - v4l2: fix display size for NV12 output pool.
        - v4l2: handle EOS (EPIPE and draining)
        - v4l2: vp8 and mpeg4 decoding and encoding.
        - v4l2: hevc and vp9 support.
        - v4l2: generate EOF on dequeue errors.
        - v4l2: h264_mp4toannexb filtering.
        - v4l2: fixed make install and fate issues.
        - v4l2: codecs enabled/disabled depending on pixfmt defined
        - v4l2: pass timebase/framerate to the context
        - v4l2: runtime decoder reconfiguration.
        - v4l2: add more frame information
        - v4l2: free hardware resources on last reference being released
        - v4l2: encoding: disable b-frames for upstreaming (patch required)

    [1] https://lwn.net/Articles/697956/

    System Level view:
        v42l_m2m_enc/dec --> v4l2_m2m --> v4l2_context --> v4l2_buffers

    Reviewed-by: Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
    Reviewed-by: Alexis Ballier <aballier@gentoo.org>
    Tested-by: Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>

Signed-off-by: wm4 <nfxjfg@googlemail.com>

1 files changed, 228 insertions, 0 deletions

diff --git a/libavcodec/v4l2_m2m_dec.c b/libavcodec/v4l2_m2m_dec.c
new file mode 100644
index 0000000000..958cdc522b
--- /dev/null
+++ b/libavcodec/v4l2_m2m_dec.c
@@ -0,0 +1,228 @@
+/*
+ * V4L2 mem2mem decoders
+ *
+ * Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
+ * Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
+ *
+ * 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 <linux/videodev2.h>
+#include <sys/ioctl.h>
+#include "libavutil/pixfmt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/opt.h"
+#include "libavcodec/avcodec.h"
+#include "libavcodec/decode.h"
+
+#include "v4l2_context.h"
+#include "v4l2_m2m.h"
+#include "v4l2_fmt.h"
+
+static int v4l2_try_start(AVCodecContext *avctx)
+{
+    V4L2m2mContext *s = avctx->priv_data;
+    V4L2Context *const capture = &s->capture;
+    V4L2Context *const output = &s->output;
+    struct v4l2_selection selection;
+    int ret;
+
+    /* 1. start the output process */
+    if (!output->streamon) {
+        ret = ff_v4l2_context_set_status(output, VIDIOC_STREAMON);
+        if (ret < 0) {
+            av_log(avctx, AV_LOG_DEBUG, "VIDIOC_STREAMON on output context\n");
+            return ret;
+        }
+    }
+
+    if (capture->streamon)
+        return 0;
+
+    /* 2. get the capture format */
+    capture->format.type = capture->type;
+    ret = ioctl(s->fd, VIDIOC_G_FMT, &capture->format);
+    if (ret) {
+        av_log(avctx, AV_LOG_WARNING, "VIDIOC_G_FMT ioctl\n");
+        return ret;
+    }
+
+    /* 2.1 update the AVCodecContext */
+    avctx->pix_fmt = ff_v4l2_format_v4l2_to_avfmt(capture->format.fmt.pix_mp.pixelformat, AV_CODEC_ID_RAWVIDEO);
+    capture->av_pix_fmt = avctx->pix_fmt;
+
+    /* 3. set the crop parameters */
+    selection.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    selection.r.height = avctx->coded_height;
+    selection.r.width = avctx->coded_width;
+    ret = ioctl(s->fd, VIDIOC_S_SELECTION, &selection);
+    if (!ret) {
+        ret = ioctl(s->fd, VIDIOC_G_SELECTION, &selection);
+        if (ret) {
+            av_log(avctx, AV_LOG_WARNING, "VIDIOC_G_SELECTION ioctl\n");
+        } else {
+            av_log(avctx, AV_LOG_DEBUG, "crop output %dx%d\n", selection.r.width, selection.r.height);
+            /* update the size of the resulting frame */
+            capture->height = selection.r.height;
+            capture->width  = selection.r.width;
+        }
+    }
+
+    /* 4. init the capture context now that we have the capture format */
+    if (!capture->buffers) {
+        ret = ff_v4l2_context_init(capture);
+        if (ret) {
+            av_log(avctx, AV_LOG_DEBUG, "can't request output buffers\n");
+            return ret;
+        }
+    }
+
+    /* 5. start the capture process */
+    ret = ff_v4l2_context_set_status(capture, VIDIOC_STREAMON);
+    if (ret) {
+        av_log(avctx, AV_LOG_DEBUG, "VIDIOC_STREAMON, on capture context\n");
+        return ret;
+    }
+
+    return 0;
+}
+
+static int v4l2_prepare_decoder(V4L2m2mContext *s)
+{
+    struct v4l2_event_subscription sub;
+    V4L2Context *output = &s->output;
+    int ret;
+
+    /**
+     * requirements
+     */
+    memset(&sub, 0, sizeof(sub));
+    sub.type = V4L2_EVENT_SOURCE_CHANGE;
+    ret = ioctl(s->fd, VIDIOC_SUBSCRIBE_EVENT, &sub);
+    if ( ret < 0) {
+        if (output->height == 0 || output->width == 0) {
+            av_log(s->avctx, AV_LOG_ERROR,
+                "the v4l2 driver does not support VIDIOC_SUBSCRIBE_EVENT\n"
+                "you must provide codec_height and codec_width on input\n");
+            return ret;
+        }
+    }
+
+    return 0;
+}
+
+static int v4l2_receive_frame(AVCodecContext *avctx, AVFrame *frame)
+{
+    V4L2m2mContext *s = avctx->priv_data;
+    V4L2Context *const capture = &s->capture;
+    V4L2Context *const output = &s->output;
+    AVPacket avpkt = {0};
+    int ret;
+
+    ret = ff_decode_get_packet(avctx, &avpkt);
+    if (ret < 0 && ret != AVERROR_EOF)
+        return ret;
+
+    if (s->draining)
+        goto dequeue;
+
+    ret = ff_v4l2_context_enqueue_packet(output, &avpkt);
+    if (ret < 0) {
+        if (ret != AVERROR(ENOMEM))
+           return ret;
+        /* no input buffers available, continue dequeing */
+    }
+
+    if (avpkt.size) {
+        ret = v4l2_try_start(avctx);
+        if (ret)
+            return 0;
+    }
+
+dequeue:
+    return ff_v4l2_context_dequeue_frame(capture, frame);
+}
+
+static av_cold int v4l2_decode_init(AVCodecContext *avctx)
+{
+    V4L2m2mContext *s = avctx->priv_data;
+    V4L2Context *capture = &s->capture;
+    V4L2Context *output = &s->output;
+    int ret;
+
+    /* if these dimensions are invalid (ie, 0 or too small) an event will be raised
+     * by the v4l2 driver; this event will trigger a full pipeline reconfig and
+     * the proper values will be retrieved from the kernel driver.
+     */
+    output->height = capture->height = avctx->coded_height;
+    output->width = capture->width = avctx->coded_width;
+
+    output->av_codec_id = avctx->codec_id;
+    output->av_pix_fmt  = AV_PIX_FMT_NONE;
+
+    capture->av_codec_id = AV_CODEC_ID_RAWVIDEO;
+    capture->av_pix_fmt = avctx->pix_fmt;
+
+    ret = ff_v4l2_m2m_codec_init(avctx);
+    if (ret) {
+        av_log(avctx, AV_LOG_ERROR, "can't configure decoder\n");
+        return ret;
+    }
+
+    return v4l2_prepare_decoder(s);
+}
+
+#define OFFSET(x) offsetof(V4L2m2mContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+    V4L_M2M_DEFAULT_OPTS,
+    { "num_capture_buffers", "Number of buffers in the capture context",
+        OFFSET(capture.num_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 20, INT_MAX, FLAGS },
+    { NULL},
+};
+
+#define M2MDEC(NAME, LONGNAME, CODEC, bsf_name) \
+static const AVClass v4l2_m2m_ ## NAME ## _dec_class = {\
+    .class_name = #NAME "_v4l2_m2m_decoder",\
+    .item_name  = av_default_item_name,\
+    .option     = options,\
+    .version    = LIBAVUTIL_VERSION_INT,\
+};\
+\
+AVCodec ff_ ## NAME ## _v4l2m2m_decoder = { \
+    .name           = #NAME "_v4l2m2m" ,\
+    .long_name      = NULL_IF_CONFIG_SMALL("V4L2 mem2mem " LONGNAME " decoder wrapper"),\
+    .type           = AVMEDIA_TYPE_VIDEO,\
+    .id             = CODEC ,\
+    .priv_data_size = sizeof(V4L2m2mContext),\
+    .priv_class     = &v4l2_m2m_ ## NAME ## _dec_class,\
+    .init           = v4l2_decode_init,\
+    .receive_frame  = v4l2_receive_frame,\
+    .close          = ff_v4l2_m2m_codec_end,\
+    .bsfs           = bsf_name, \
+};
+
+M2MDEC(h264,  "H.264", AV_CODEC_ID_H264,       "h264_mp4toannexb");
+M2MDEC(hevc,  "HEVC",  AV_CODEC_ID_HEVC,       "hevc_mp4toannexb");
+M2MDEC(mpeg1, "MPEG1", AV_CODEC_ID_MPEG1VIDEO, NULL);
+M2MDEC(mpeg2, "MPEG2", AV_CODEC_ID_MPEG2VIDEO, NULL);
+M2MDEC(mpeg4, "MPEG4", AV_CODEC_ID_MPEG4,      NULL);
+M2MDEC(h263,  "H.263", AV_CODEC_ID_H263,       NULL);
+M2MDEC(vc1 ,  "VC1",   AV_CODEC_ID_VC1,        NULL);
+M2MDEC(vp8,   "VP8",   AV_CODEC_ID_VP8,        NULL);
+M2MDEC(vp9,   "VP9",   AV_CODEC_ID_VP9,        NULL);