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, 121 insertions, 0 deletions

diff --git a/libavcodec/v4l2_buffers.h b/libavcodec/v4l2_buffers.h
new file mode 100644
index 0000000000..8901a0952f
--- /dev/null
+++ b/libavcodec/v4l2_buffers.h
@@ -0,0 +1,121 @@
+/*
+ * V4L2 buffer helper functions.
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_V4L2_BUFFERS_H
+#define AVCODEC_V4L2_BUFFERS_H
+
+enum V4L2Buffer_status {
+    V4L2BUF_AVAILABLE,
+    V4L2BUF_IN_DRIVER,
+    V4L2BUF_RET_USER,
+};
+
+/**
+ * V4L2Buffer (wrapper for v4l2_buffer management)
+ */
+typedef struct V4L2Buffer {
+    /* each buffer needs to have a reference to its context */
+    struct V4L2Context *context;
+
+    /* keep track of the mmap address and mmap length */
+    struct V4L2Plane_info {
+        int bytesperline;
+        void * mm_addr;
+        size_t length;
+    } plane_info[VIDEO_MAX_PLANES];
+
+    int num_planes;
+
+    /* the v4l2_buffer buf.m.planes pointer uses the planes[] mem */
+    struct v4l2_buffer buf;
+    struct v4l2_plane planes[VIDEO_MAX_PLANES];
+
+    int flags;
+    enum V4L2Buffer_status status;
+
+} V4L2Buffer;
+
+/**
+ * Extracts the data from a V4L2Buffer to an AVFrame
+ *
+ * @param[in] frame The AVFRame to push the information to
+ * @param[in] buf The V4L2Buffer to get the information from
+ *
+ * @returns 0 in case of success, EINVAL if the number of planes is incorrect,
+ * ENOMEM if the AVBufferRef cant be created.
+ */
+int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *buf);
+
+/**
+ * Extracts the data from a V4L2Buffer to an AVPacket
+ *
+ * @param[in] pkt The AVPacket to push the information to
+ * @param[in] buf The V4L2Buffer to get the information from
+ *
+ * @returns 0 in case of success, EINVAL if the number of planes is incorrect,
+ * ENOMEM if the AVBufferRef cant be created.
+ *
+ */
+int ff_v4l2_buffer_buf_to_avpkt(AVPacket *pkt, V4L2Buffer *buf);
+
+/**
+ * Extracts the data from an AVPacket to a V4L2Buffer
+ *
+ * @param[in]  frame AVPacket to get the data from
+ * @param[in]  avbuf V4L2Bfuffer to push the information to
+ *
+ * @returns 0 in case of success, negative otherwise
+ */
+int ff_v4l2_buffer_avpkt_to_buf(const AVPacket *pkt, V4L2Buffer *out);
+
+/**
+ * Extracts the data from an AVFrame to a V4L2Buffer
+ *
+ * @param[in]  frame AVFrame to get the data from
+ * @param[in]  avbuf V4L2Bfuffer to push the information to
+ *
+ * @returns 0 in case of success, negative otherwise
+ */
+int ff_v4l2_buffer_avframe_to_buf(const AVFrame *frame, V4L2Buffer* out);
+
+/**
+ * Initializes a V4L2Buffer
+ *
+ * @param[in]  avbuf V4L2Bfuffer to initialize
+ * @param[in]  index v4l2 buffer id
+ *
+ * @returns 0 in case of success, negative otherwise
+ */
+int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index);
+
+/**
+ * Enqueues a V4L2Buffer
+ *
+ * @param[in] avbuf V4L2Bfuffer to push to the driver
+ *
+ * @returns 0 in case of success, negative otherwise
+ */
+int ff_v4l2_buffer_enqueue(V4L2Buffer* avbuf);
+
+
+#endif // AVCODEC_V4L2_BUFFERS_H