generalize code for simple encoder wrappers (#40)

- generalize code for hardware/software/encoder wrappers
- use supplied software pixel format in non-hardware path
- minimal documentation for generalized implementation

Closes #39

README.md

@@ -3,9 +3,10 @@
 This library wraps hardware video encoding and scaling in a simple interface.
 There are no performance loses (at the cost of library flexibility).
 
-Currently it supports VAAPI and NVENC (no scaling).\
+Currently it supports VAAPI, NVENC, software-like wrappers (e.g. nvmpi) and software (e.g. libx264).\
 Various codecs are supported (H.264, HEVC, ...).\
-VBR and CQP modes are supported (e.g. streaming and later editting).
+VBR and CQP modes are supported (e.g. streaming and later editting).\
+Scaling is only supported for VAAPI.\
 
 See library [documentation](https://bmegli.github.io/hardware-video-encoder/group__interface.html).
 
@@ -78,6 +79,9 @@ make
 
 ## Nvidia NVENC
 ./hve-encode-raw-h264 10 h264_nvenc
+
+## Software
+./hve-encode-raw-h264 10 libx264
 ```
 
 ``` bash

examples/hve_encode_raw_h264.c

@@ -143,6 +143,7 @@ int process_user_input(int argc, char* argv[])
 		fprintf(stderr, "%s 10 h264_vaapi\n", argv[0]);
 		fprintf(stderr, "%s 10 h264_vaapi /dev/dri/renderD128\n", argv[0]);
 		fprintf(stderr, "%s 10 h264_nvenc\n", argv[0]);
+		fprintf(stderr, "%s 10 libx264 # (software encoder)\n", argv[0]);
 
 		return -1;
 	}

hve.c

@@ -42,7 +42,7 @@ struct hve
 
 static struct hve *hve_close_and_return_null(struct hve *h, const char *msg);
 
-static int init_hwframes_context(struct hve* h, const struct hve_config *config);
+static int init_hwframes_context(struct hve* h, const struct hve_config *config, enum AVHWDeviceType device_type);
 static int init_hardware_scaling(struct hve *h, const struct hve_config *config);
 
 static enum AVHWDeviceType hve_hw_device_type(const char *encoder);
@@ -74,16 +74,11 @@ struct hve *hve_init(const struct hve_config *config)
 
 	//specified encoder or NULL / empty string for H.264 VAAPI
 	const char *encoder = (config->encoder != NULL && config->encoder[0] != '\0') ? config->encoder : "h264_vaapi";
-	//specified device or NULL / empty string for default
-	const char *device = (config->device != NULL && config->device[0] != '\0') ? config->device : NULL;
 
 	enum AVHWDeviceType device_type = hve_hw_device_type(encoder);
 
 	if(device_type == AV_HWDEVICE_TYPE_NONE)
-		return hve_close_and_return_null(h, "hve doesn't support selected encoder");
-
-	if( (err = av_hwdevice_ctx_create(&h->hw_device_ctx, device_type, device, NULL, 0) ) < 0)
-		return hve_close_and_return_null(h, "failed to create hardware device context");
+		fprintf(stderr, "hve: not using hardware device type (enoder wrapper, software or hardware not supported by hve)\n");
 
 	if(!(codec = avcodec_find_encoder_by_name(encoder)))
 		return hve_close_and_return_null(h, "could not find encoder");
@@ -100,10 +95,6 @@ struct hve *hve_init(const struct hve_config *config)
 	h->avctx->time_base = (AVRational){ 1, config->framerate };
 	h->avctx->framerate = (AVRational){ config->framerate, 1 };
 	h->avctx->sample_aspect_ratio = (AVRational){ 1, 1 };
-	h->avctx->pix_fmt = hve_hw_pixel_format(device_type);
-
-	if(h->avctx->pix_fmt == AV_PIX_FMT_NONE)
-		return hve_close_and_return_null(h, "could not find hardware pixel format for encoder");
 
 	if(config->profile)
 		h->avctx->profile = config->profile;
@@ -123,8 +114,11 @@ struct hve *hve_init(const struct hve_config *config)
 		return hve_close_and_return_null(h, NULL);
 	}
 
-	if((err = init_hwframes_context(h, config)) < 0)
-		return hve_close_and_return_null(h, "failed to set hwframe context");
+	h->avctx->pix_fmt = h->sw_pix_fmt;
+
+	if(device_type != AV_HWDEVICE_TYPE_NONE)
+		if((err = init_hwframes_context(h, config, device_type)) < 0)
+			return hve_close_and_return_null(h, "failed to set hwframe context");
 
 	AVDictionary *opts = NULL;
 
@@ -207,12 +201,21 @@ static struct hve *hve_close_and_return_null(struct hve *h, const char *msg)
 	return NULL;
 }
 
-static int init_hwframes_context(struct hve* h, const struct hve_config *config)
+static int init_hwframes_context(struct hve* h, const struct hve_config *config, enum AVHWDeviceType device_type)
 {
 	AVBufferRef* hw_frames_ref;
 	AVHWFramesContext* frames_ctx = NULL;
 	int err = 0, depth;
 
+	//specified device or NULL / empty string for default
+	const char *device = (config->device != NULL && config->device[0] != '\0') ? config->device : NULL;
+
+	if( (h->avctx->pix_fmt = hve_hw_pixel_format(device_type)) == AV_PIX_FMT_NONE)
+		return HVE_ERROR_MSG("could not find hardware pixel format for encoder");
+
+	if( av_hwdevice_ctx_create(&h->hw_device_ctx, device_type, device, NULL, 0) < 0)
+		return HVE_ERROR_MSG("failed to create hardware device context");
+
 	if(!(hw_frames_ref = av_hwframe_ctx_alloc(h->hw_device_ctx)))
 		return HVE_ERROR_MSG("failed to create hardware frame context");
 
@@ -349,7 +352,7 @@ static enum AVPixelFormat hve_hw_pixel_format(enum AVHWDeviceType type)
 {
 	if(type == AV_HWDEVICE_TYPE_VAAPI)
 		return AV_PIX_FMT_VAAPI;
-	else if(type == AV_PIX_FMT_CUDA);
+	else if(type == AV_HWDEVICE_TYPE_CUDA)
 		return AV_PIX_FMT_CUDA;
 
 	return AV_PIX_FMT_NONE;
@@ -410,8 +413,9 @@ int hve_send_frame(struct hve *h,struct hve_frame *frame)
 	memcpy(h->sw_frame->linesize, frame->linesize, sizeof(frame->linesize));
 	memcpy(h->sw_frame->data, frame->data, sizeof(frame->data));
 
-	if(hw_upload(h) < 0)
-		return HVE_ERROR_MSG("failed to upload frame data to hardware");
+	if(h->hw_device_ctx)
+		if(hw_upload(h) < 0)
+			return HVE_ERROR_MSG("failed to upload frame data to hardware");
 
 	if(h->filter_graph)
 		return scale_encode(h);
@@ -463,7 +467,9 @@ static int scale_encode(struct hve *h)
 
 static int encode(struct hve *h)
 {
-	if(avcodec_send_frame(h->avctx, h->hw_frame) < 0)
+	AVFrame *frame = h->hw_frame ? h->hw_frame : h->sw_frame;
+
+	if(avcodec_send_frame(h->avctx, frame) < 0)
 		return HVE_ERROR_MSG("send_frame error");
 
 	return HVE_OK;

hve.h

@@ -48,7 +48,7 @@ struct hve;
  *
  * The width and height are dimmensions of the encoded data.
  *
- * To enable hardware accelerated scaling specify non-zero
+ * To enable hardware accelerated scaling (VAAPI only) specify non-zero
  * input_width and input_height different from width and height.
  *
  * The device can be:
@@ -63,10 +63,11 @@ struct hve;
  * - NULL or empty string for "h264_vaapi"
  * - valid ffmpeg encoder
  *
- * You may check encoders supported by your hardware with ffmpeg:
+ * You may check encoders supported by your hardware/software with ffmpeg:
  * @code
  * ffmpeg -encoders | grep vaapi
  * ffmpeg -encoders | grep nvenc
+ * ffmpeg -encoders | grep h264
  * @endcode
  *
  * Encoders typically can be:
@@ -78,10 +79,13 @@ struct hve;
  * - vp9_vaapi
  * - h264_nvenc
  * - hevc_nvenc
+ * - h264_nvmpi (custom Jetson specific FFmpeg build)
+ * - hevc_nvmpi (custom Jetson specific FFmpeg build)
+ * - libx264 (software)
  *
  * The pixel_format (format of what you upload) typically can be:
  * - nv12 (this is generally safe choice)
- * - yuv420p
+ * - yuv420p (required for some encoders)
  * - yuyv422
  * - uyvy422
  * - yuv422p
@@ -93,6 +97,8 @@ struct hve;
  * @code
  * ffmpeg -h encoder=h264_vaapi
  * ffmpeg -h encoder=h264_nvenc
+ * ffmpeg -h encoder=h264_nvmpi
+ * ffmpeg -h encoder=libx264
  * @endcode
  *
  * There are no software color conversions in this library.